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#1
02-14-2012, 07:03 AM
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39t sprocket
I have been reading alot online about the low and mid range gain on my 150 by going with a 39t sprocket and longer chain!
Can anyone that has done this mod confirm it ! Is it wort it ? My buggies have a great top end speed but had flat spots in low and mid ! Thanks to Sycarms i adjusted the valves and got alot more out of the old girls but always looking for alittle more. I ride on ruff flat trails here in Florida and lots of loose sand and saw Palmettos on the ground! On another cart i have with tons of low end we find it easier to drift and power spin in the tight turns do to the sand ! Triing to get the crossfire 150,s to do the same! Any help would be great Thanks |
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#2
02-15-2012, 11:16 AM
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It does help considerably, another option is to change the internal ratio. I believe there are 4 different sets of internal gearing combos. Sorry but it has been awhile, I'm sure Tom can fill you in more on this option.
__________________
09 Joyner Sand Viper 250 08 Joyner Sand Viper 250 2009 Joylaris 400 Screamer http://www.youtube.com/watch?v=eeulR4W1_PU |
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#5
02-17-2012, 12:05 PM
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Sand eat hp big time
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http://www.youtube.com/watch?v=IUgir...ature=g-t=2668 FABRICATION ITS HARDER THAN YOU THINK |
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#7
02-18-2012, 10:37 PM
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I just put the 39T on my Spiderbox yesterday and it has much more power! I have tons of mods on it already, but I wanted the 39T so I can climb hills much easier and if I have a passenger I'd have no problems toting them around.
My engine is also geared very low (I think it's the lowest) 13/40 internal.. and 16/39 external. So it's not that fastest but on the trails it's hard to keep up with me. I also have an Uni intake type, 125 jet, orange cdi, red coil, iridium spark plug, 10g rollers, yellow clutch springs and contra spring, Reverse, 22" mud tires on the back 19"s up front. Lyon do you have a link to the weld on hub and sprocket? just curious to what it is. Last edited by T3beatz; 02-19-2012 at 07:56 PM. |
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#8
02-19-2012, 07:02 AM
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looks like im going to spring for it then , I know im going to have to either lengthen my chain by 4 links or just buy new ones, Grrrrr just bought chains for both buggies
 Yes would love to see the wilded one . I Also have some play in the rear hubs of one of my crossfires ! How much play should thier be ? I have weled everthing on it now so i noticed a new sound i have not herd before and track it to the rear hubs 1/4 inch slop at the hubs. |
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#9
02-19-2012, 07:15 AM
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Quote:
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which one of these do you think made the *most* difference right away ? |
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#10
02-19-2012, 09:33 AM
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My Howhit on the Yerf is a 13/40 gear combination. Only way to know FOR SURE is to remove the final drive cover and count the teeth.
Or if you can find any info from the manufacturer... Say maybe in a repair manual? (and that's only if a previous owner didn't change them out) |
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#11
02-19-2012, 10:46 AM
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I know you asked T3, but I've kept pretty good records of my performance gains after each modification to my Yerfdog 3206.
Stock Spiderbox configuration: 13/40 internal gears, 13T engine sprocket, 31T axle sprocket, and 743 20 30 Gates belt. All measurements were taken with a Garmin Etrex handheld GPS, on concrete, with a set distance (approx 300'), on the same "track". 22.3 MPH as is from previous owner (stock tires, slightly deflated, stiff front suspension) 23.1 MPH performance coil, performance CDI (both orange from Ebay), no air filter and 125 main jet 23.7 MPH opened muffler opening (1/2" stock VS. 3/4") 24.9 MPH home ported head and port match intake manifold 26.3 MPH MAX SPEED (first run on street) 25.2 MPH 10g Dr. Pulley sliders with cleaned/lubed CVT, and deglaze clutch and bell 29.8 MPH MAX SPEED 26.8 MPH New tires and bearings (22" rear), FMF slip on exhaust, UNI air filter with 6" extension 33.2 MPH MAX SPEED 27.2 MPH 8" extension for air filter 33.0 MPH MAX SPEED 28.0 MPH NCY CDI (orange with aluminum housing) 33.0 MPH MAX SPEED All readings were taken with all upgrades added to one another. Only the air filter extension was substituted. Round 2 Test and tune  28.6 MPH 12 gram Dr. Pulley sliders and header wrap for 7" 35.3 MPH MAX 30.1 MPH A11 cam installed (needs larger pilot jet) 38.9 MPX MAX Last test and tune session with basic "stock" engine: 29.6 MPH with stock rollers 37 MPH MAX 30.2 MPH with Dr. Pulley variator and 12g sliders 38.3 MPH MAX I tried getting readings with a 6", 7", and 8" red neck tube extension, but they were all around the same speeds in accel. I didn't have the jetting nailed down yet with the A11 cam until after I made the passes. The kart was blubbering off the line. Ended up using 35 pilot, 2 1/2 turns on the mixture screw, and a 122.5 main jet for good reults. So no improvement from the last test session. 12g sliders in the stock variator seemed to work best for me. OK, so now I have the 62mm BBK kit installed 32.7 MPH in 300' Max speed 40.2 MPH Time to install the good stuff...... 
Last edited by xlint89; 11-09-2014 at 10:18 PM. |
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#12
02-19-2012, 05:10 PM
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xlint89 - cool, glad you did these measurements... any gut feel for the best for the most upgrade ? jets for example? I know each upgrade tends to need another (more gas needs more exhaust). I did the air filter and jet, and did feel and hear a difference, but never measured.
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#13
02-19-2012, 07:12 PM
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Great info
 I'm curious--How much did you spend to get 10 more MPH? |
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#14
02-19-2012, 07:15 PM
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Quote:
Oh, and I checked my gear count when I had the engine broken down to change out the output shaft, to mount the reverse, I have the Howhit GY6. I need to test my speed, but I've put about $120.00 bucks into the engine so far for upgrades. All purchased from ebay Orang CDI $15.00 Foam Air intake 9.99 intake oil 9.99 Jet set 11.05 shipped (115,120,125,130,135) coil/boot 13.68 iridium spark plug 9.99 10g rollers 9.99 1500 contra spring 11.00 1500 clutch springs 9.95 a different place 39T sprocket 21.95 http://www.highrpmracer.com/rear-spr...0-p-11553.html 38 pilot jet 4.95 http://www.scrappydogscooters.com/12...OKE_PARTS.html All these upgrades helped tons on my trails I can tell the difference big time on the big hills. Before when I would climb them I could notice the buggy bogging down toward the top a little, and the pedal would have to be floored, but now it spins the tires if I give it full throttle on the same hills, and I don't have to have speed to climb them. Since I've moved to the 39T sprocket I'm going install a set of 12g or 13g sliders to get my speed back. I'm also going to be getting a Performance Muffler soon, maybe one of the 90 dollar ones from ebay, I know that is probably the most restrictive part in my setup now. http://www.ebay.com/itm/Silver-scoot...ht_1901wt_1133 T.J. Last edited by T3beatz; 02-19-2012 at 08:06 PM. |
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#16
02-19-2012, 10:18 PM
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Quote:
UNI filter $20 PVC extension $4 rejet carb FREE (I have a ton of jets available from working on my skis) Performance coil $15 Performance CDI $20 NCY CDI (preferred) $35 FMF slip on muffler (used on Ebay $30 shipped) Home ported head with port matching FREE Dr. Pulley 10g sliders $25 Clean/lube CVT FREE Deglaze clutch and bell FREE Total = $ 130 Total performance gained = 3+ MPH in 300' This is what you can REALLY feel. Takes off much better, I'm sure I'll be able to climb any hills much easier too. Last edited by xlint89; 02-19-2012 at 11:06 PM. |
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#17
02-19-2012, 10:45 PM
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Quote:
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 Please understand that the first posted speed was in rough shape, and NOT max speed. So technically, I didn't gain 10 MPH. I never did a MAX speed baseline run "as is". Total $475 plus some shipping costs as well  But, as you can see, it's greatly improved the performance, the ride, and the fun factor. So it was well worth it.  However, I am not done yet. I am looking to gain more top speed still. What I have left to test though:  Dr. Pulley variator 12g sliders I would also like to try the Kidnme performance clutch pulley, bigger belt, and Dr. P variator and see what that gets me.  This is all done with the stock 150cc engine. I've got other plans once testing is over. 
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#18
02-20-2012, 01:36 AM
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As far as speed goes the 10g sliders or rollers are going to limit your speed a tad (not heavy enough to push the variator all the way out, especially if you have higher rated contra springs installed), but give you good low end power.
If your going strictly for speed then simple other mods will get you there. The Dr. pulley variator looks good but I would like to try the DR 2 performance variator (but that fact that it does not have a fan is weird to me). I'm gonna test my speed next time I go out. My goal is about 25-30mph, but will get there pretty fast, and have great power for trails. Last edited by T3beatz; 02-20-2012 at 01:44 AM. |
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#19
02-20-2012, 06:27 AM
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This is all great info for anyone moding a gy6 120 , I thank you all very much.
The trails i ride here in florida have no real hills to speak of yet ! I need to barrow a dozer for the weekend. I am on sandy tails with lots of saw palmettos , "small palm trees " anout 2 to 3 feet tall ! I had a farmer use his disc cutter on some of it to clear the saw palmettos out ! So at the end of the day i need good low end grunt to turn out of the corners , My back trails only have 2 or three spots that i can hit the rev limiter. So the next upgrades will be a 39t and a nyc cdi no rev limit. the stock buggies would not break 20 mph. Keeping in mind i got them used and with no upgrades at all. What ive done so far. 130 jet orange coil dr pulley clutch dr pulley teflon vibrator with 10g rollers 1500 rpm yellow spring uni ait filter polished intake manifold |
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#20
02-20-2012, 07:02 AM
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Oh boy..... I hope the GF doesn't see this thread!!!
Total $475 plus some shipping costs as well think like a politician, it's all how you spin it... "Look honey, I was not wasting money hanging out at bars, chasing women.... I was here at home with you, building something you can enjoy with me"
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#21
02-20-2012, 11:59 AM
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Quote:
 drillpvt, seems you have done a few good upgrades already, and if I'm not mistaken I think the crossfire has the howhit gy6 engine also so it should have the low internal gearing (13/40). the 39T sprocket should get you a little more low end grunt and should help move the crossfire around in that sand a little better. Next I would mod the current muffler or buy a performance one for a little more HP. |
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#22
02-20-2012, 02:25 PM
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I have moded the stock pipe , Sorry i should have posted that . It is a howit gy6 , next is the 39t sprocket , then Cam upgrade then carb. alot of people have told me the 30 to 32 mil pumper carbs wont do to much with out a better Cam . Never done a cam before so it will be intresting ! but im only doning that on one of the Crossfires ! I am looking for a good used 250cc on craiglist and online to throw into the other one.
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#23
02-20-2012, 02:59 PM
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Quote:
The big bore kit's can be found for as low as 80-90 bucks, but you will have to have the crank case machined for any big bore kit over 59mm The 59mm big bore kit will take you up to about 158cc's over the stock 149 (or 148 in the howhits). 63mm will get you about 180cc's. (I'm sure you may know all of this, but someone who may be looking over this thread may want to know). just found this... http://www.**********.com/buggy-tech...ore-stroker/16 big bore kit 59mm... http://www.ebay.com/itm/157QMJ-GY6-p...#ht_912wt_1396 Last edited by T3beatz; 02-20-2012 at 03:15 PM. Reason: link |
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#24
02-20-2012, 03:44 PM
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this is what happens when you buy a bigger intake for the crossfire gy6 buggies. The intake is about 3/4 of a inch longer were the carb goes on ! the carb no longer fits into the engine cage the right way , it also hits the top engine mont ! grrrrrr, I paid a whopping 22.00 dollars for this thing so being the redneck i am it was going on it one way or another lol .
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#25
02-20-2012, 04:29 PM
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So that's what a spare Spiderbox A-arm get's used for!!!!!
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#27
02-20-2012, 06:12 PM
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Quote:
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#28
02-20-2012, 06:19 PM
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The connector that came with my uni filter is only 3 inches but the whole problem was the cross bar was in the way , when i put on the polished intake manifold going into the motor , It was the new part that was taller and longer then the stock . Airfilter use to fit nicely under the cross bar . now its dead in line with it. Hence the cutting and butcher job welding.
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#29
02-20-2012, 07:16 PM
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@ drillpvt, got to do what ya got to do some times, as long as it works.
I just went out and did a few speed tests with my Yerf with the 39T sprocket. The first couple runs were ok, but something was wrong on the top end, I was getting horrible popping and it felt as if I was stepping on the breaks slightly, Top speed was 26mph. I went back into the garage and checked my plug and it was on the white side (lean). So I took out my stash of jets and removed the 125 that was in and replaced it with a 130. Went back out for a few more runs and the engine sounded much better still a slight popping once I got to the very peak of speed but I was able to hit 30mph with no problems. I think I'm going to have to move to a 132.5 jet for now, This is puzzling because I still have the stock muffler on it, I didn't think I would need such a high jet size. My friends have told me that My muffler sounds different from theirs, it has a beefier sound (we all have howhit gy6's with the stock mufflers). So all in all with the 39T sprocket you can still get decent top speeds with a lot of low end power. Going to the 12G sliders will probably get me 2-3 more mph. |
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#30
02-21-2012, 12:38 AM
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Quote:
Stock contra spring is in it. I'm thinking of trying the ball bearing spring base though. http://www.sycpowersports.com/index....id=66&incid=29 Supposed to prevent the spring from binding = smoother transitions And it will actually stiffen the stock spring 15% I read due to the raised height of the base because of the bearings and double "seat" if you will... |
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#31
02-21-2012, 12:40 AM
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#32
02-21-2012, 12:47 AM
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I kind of find that to be odd since the stock intake length on my Yerf was 8"... But, as you can see the 8" extension yielded almost 1/2 MPH gain over the 6" in the 300' test, and only lost .2 MPH on MAX speed. That's the best I could come up with |
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#33
02-21-2012, 01:09 AM
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Quote:
Post #20 shows a Howhit bore http://buggymasters.com/forum/showthread.php?t=2665 I think the only viable option for guys with this motor are the 58.5mm/59mm bbk and a stroker crank. Plus I've read the 63mm kit gets to be pretty thin on the cyl walls. Not good from a structuarl stand point. I think most prefer the 62mm kit with slightly thicker cyl walls for longevity. Last edited by xlint89; 02-21-2012 at 01:13 AM. |
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#34
02-21-2012, 01:32 AM
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I personally wouldn't go past the 59mm (seems easy enough to install), the stroker crank looks appealing but $200 bucks and a ton of work later doesn't! lol. I'm sure the 59mm will be plenty of power for me. Right now as is I'm sure it has enough power to get through most of the trails we have around here, and may even keep up with some 250's!
 I'ts a 150, I'll try and get as much power out of it as I can without going overboard on spending. I don't want to put 1000 bucks into this buggy, knowing I can find a decent 250 for $1200-$1500. @xlint89 I think that's about right, you can still get it bored to a certain point. here is a vid you can see how thin the walls are and they guy still has to bore it out for the 63mm jug. The inner diameter is 63mm, the walls are thinner so you don't have to bore out as much on the crankcase. http://www.youtube.com/watch?v=R1GFv...eature=channel Last edited by T3beatz; 02-21-2012 at 01:52 AM. |
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#35
02-21-2012, 02:30 PM
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If you have to split the case for any reason or replace a stock crank shaft, the stroker crank should be on your parts list. It will provide more torque (which is what any 150 needs). You'll have to decide if it's worth your time splitting open a good engine to install a crank.
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#36
02-21-2012, 04:46 PM
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Quote:
It's been recommended to me to change out the stock starter clutch if you're going to be adding more power/compression to the engine. If you're going that far in, might as well go a little bit more. Ceramic/Nikasil 59mm with a 2.2mm stroker crank should be nice. |
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#37
03-07-2012, 10:56 PM
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Quote:
My new best mod thus far has got to be the A11 camshaft.  NOTE: that other mods must be in place to reap full benefit of the larger cam. Like ign, air filter, exhaust, etc.... |
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#38
03-07-2012, 10:58 PM
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what do you feel with the A11 over the stock?
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#39
03-07-2012, 10:59 PM
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Quote:
Last edited by xlint89; 03-07-2012 at 11:04 PM. |
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#40
03-07-2012, 11:03 PM
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Stock cam with 12g sliders was 28.6 MPH in 300' and 35.3 MPH top speed. (not bad) With A 11 cam (didn't touch jetting yet) got 30.1 MPH in 300' and 38.9 MPH MAX speed. (awesome...) That's 1.5 MPH in 300' gain and 3.5 MPH on top end just from the cam alone. And that's on top of all the other mods I've done. Guys, keep in mind, this is still with the stock variator, clutch, 24mm carb, and stock intake manifold. Last edited by xlint89; 03-07-2012 at 11:14 PM. |
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#41
03-07-2012, 11:13 PM
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And if you look, just from today's swap (12g sliders and A11 cam) I gained 2.1 MPH in the 300' test and 5.9 MPH in top speed VS. my last personal best.
I honestly feel if I would have ran her for a touch longer on the straight away, she'd might have gone a little faster. |
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#42
03-07-2012, 11:22 PM
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Oh cool stuff, Grab that 39T sprocket and see that top speed drop!
my max speed now is 30.1mph takin with my vapor, my max RPM was 9340rpms. I still have the stock muffler, and 10gram rollers, that probably is my limiting factor right now, but it's not loud and it doesn't sound to bad. I'm gonna get the sliders very soon, I just don't feel like taking my CVT cover off again. lol
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#44
03-08-2012, 12:23 AM
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I have the 16T reverse sprocket on mine, and the stock variator. I'm sure I could pick up some speed with heavier rollers/sliders, that's why I'm going to grab a set of 12grams I should be able to gain a couple mph with that.
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#46
03-08-2012, 12:42 AM
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yeah, going with the 12g sliders should keep me on par with my 10g rollers on the low end, but give me a little more speed up top (not that I need it on the trails).
but in a way changing the weights does change your gearing... If you have really light weights, like 8g ones the belt probably wont get close to the top of the variator, limiting your gearing. Now if you stick some 15g ones in the belt will ride up much higher on the variator increasing your gearing. But, you also have to factor in the Contra spring too, if you have the light weights in and 2000rpm contra springs you'll be rollin slow but with good power because of the "belt gearing" on the CVT, because the weights are so light they can't push the spring fully apart pulling the belt down on the clutch side. Run those same light weights with a 1000rpm contra spring and you'll get more speed and faster shift... Basically it all gets factored in, so in an essence it does change the gearing.
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. Last edited by T3beatz; 03-08-2012 at 01:48 AM. |
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#47
03-09-2012, 12:28 AM
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The crossfire uses the 13/40 final gears which figures 3:08. They now make a 11/43 but the case has to be cut a bit for the 43 tooth gear to fit(no big deal). Just installed it but haven't tried it yet.
TOM |
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#48
03-09-2012, 01:04 AM
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11/43, now that has to be slow! 13/40 averages around 30ish from reading around, so 11/43 has to be 25 or so.
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#49
03-09-2012, 01:26 AM
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I'm getting to the 300' mark going 43mph at 8400 rpm, but my engine is still pulling @ 9200 rpm so I figure the 3:90 ratio will get my rpm's up faster thus getting me there faster and in less time. But I'm sure I will also have to add weight to the cvt as well. My buggy will top out about 52 mph. I'm working in the 300' range since what I want is the quickest burst I gan get. Most trails have bumps and curves and on average speed ranges around 25 to 30mph and that is pushing it. But when you get to a strait the atv's will pull away from the buggy. This will give me more power to keep up with the atv's, plus I like to drag race and every bit helps.
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#50
03-09-2012, 09:20 AM
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I meant to ask what was your external gear ratio? 13/31? or 16/39?
because I have the 13/40 internal with the 16/39 external, and 30 is my max. so if your gearing is longer than that that would explain that 43mph in the 300'. T.J.
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#52
03-09-2012, 10:00 AM
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24' rear tire or 24" lol
we know what you mean. That extra 2" on the rear tire makes a difference also, that should give you a little boost in speed so that extra torque would be handy to spin the bigger tires. I'd guess most of us are running 22s on the back.
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#54
03-10-2012, 06:52 AM
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Quote:
The purpose of the tube is to reduce air turbulance and enhance velocity by straightening out the air flow before it enters the carb. Too long a tube reduces velocity. Too short doesn't give the air enough time to organize. Bends in the tube counter-act the purpose. Playing with the length does give a marked difference in throttle response and final air/fuel ratio. |
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#55
03-10-2012, 07:29 AM
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Thanks ckau, that helps a lot. right now i'm finding that a straight shot out the carb and under the cross member of about 6 inches is putting the air filter right into the rear rack bar when the swingarm compresses about 3/4 of the way into it's travel.
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#56
03-10-2012, 09:35 AM
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I have read that anything longer than 6" begins to give jetting issues? However, the Yerf Dog has an intake tube of 8" before the air filter if I remember correctly.
In my experiment, I gained slighty better acceleration with the 8" tube over the 6", but lost .2 MPH on the top with it. Maybe I should try a 7" just for kicks, and do a back to back to back test of them. Hmmm..... |
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#57
03-10-2012, 11:57 PM
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My last test session has been added above. |
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#58
03-11-2012, 08:14 PM
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what's next on the agenda to install? what are you going for speed are power?
__________________
T.J. Yerfdog Spiderbox, Uni Type air filter with 6" intake, 130 jet, Orange no-rev limit cdi, Red coil, iridium plug, 1500rpm clutch springs, 1500rpm contra spring, 13g sliders, 22" rears, 21" fronts, aftermarket reverse installed, and Trailtech Vapor. |
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#59
03-11-2012, 09:47 PM
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Installed a NCY ceramic/Nikasil coated 155cc (58.5mm) BBK today.
I REALLY wanted a stroker crank, but decided against it. (I don't ride it enough to justify it. And I'm really quite impressed with the performance gains from the few "add ons") I also installed a matching NCY ported head with ceramic coated exhaust port and valve faces. Got a matching 30mm aluminum intake manifold. I'm going to run a Keihin PE 28mm carb (round slide) Finally, I want to experiment with a different exhaust as well. Maybe try a 1" header same length as the stock pipe with the FMF slip on. (stock has 3/4" stepped up to a 1") You know, something similar to the HH exhaust. I'd love to try a tuned length exhaust though. But I can't stomach the price for the TK. Not too sure how good the MRP exhaust is??? Personally I want speed, but eventually, it'll shift to acceleration once I get on the trails. Right now it's just been blacktop and experimentation with parts. |
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#62
03-18-2012, 03:23 AM
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MRP=JUNK plain and simple.
__________________
09 Joyner Sand Viper 250 08 Joyner Sand Viper 250 2009 Joylaris 400 Screamer http://www.youtube.com/watch?v=eeulR4W1_PU |
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#66
03-21-2012, 10:20 AM
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As far as the exhaust goes, the MRP will be a great improvement over the stock exhaust but the price for not being a true tunned exhaust is its problem. But so is the Hammerhead exhaust. I will say this, I have tried the hammerhead exhaust on my 150 and actually lost power as compared to the MRP exhaust, probably due to the scavenging effect lost dur to a much less restriction, but my engine is not the average GY6. I can also say that one of my customers had the HH exhaust with my head and cam on his 250 cc and noticed a huge difference (his words) when installing the TK exhaust. The problem with the buggy world with perf. parts is they were either designed for the scooter or a non exact copy of something once designed for our buggies. The MRP exhaust was to be a cheaper alternative to the Eastside Exhaust of past but is not an exact copy so some of the low end torque gains the Eastside gave were lost in the MRP copy. |
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#67
12-25-2012, 10:26 AM
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#68
12-25-2012, 10:36 AM
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Im wondering how you modified the stock exhaust pipe. |
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#70
12-26-2012, 07:25 AM
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Thanks x. I will try to refrain from duplicating questions in multiple threads. Believe it or not at the ripe old age of 41 this is the first forum ive ever participated in. I usually do LOTS of research before doing whatever it is Im planning but never go further than looking. So you should all consider yourselves very fortunate because now that I have become a joiner......i will annoy you ALL till the end of time. MMMMWWWWAAAAHAHAHAHAHAHAAAAAA!!!!
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#73
12-28-2012, 07:00 PM
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My buggy has a 32t sprocket. I was thinking of buying a new countershaft sprocket as mine is a 16t and if I could get a 13t to replace it then it would be easy to change up between power and speed. Only problem is all the places Ive found to get them are "bike" specific. Year,make model of motorcycle is needed to get the sprocket. That helps me not one bit. If I properly uploaded my image it will show what my sprocket looks like. So wondering if anyone has an idea of how to get one besides going to the local motorcycle shop and paying twice as much as internet.
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#74
12-28-2012, 07:15 PM
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How about making one fit your application?
https://www.*************.com/sort.a...EN=20&PageNo=6 http://tsc.tractorsupply.com/search#...&sliredirect=1 http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40 |
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#75
12-28-2012, 07:52 PM
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The one on ebay was for a 520 chain and mine is 530. Will it make a difference?
If not Ill get that because it's just what I'm looking for. 3 teeth difference on the small sprocket would make a sizable difference in power wouldn't it? |
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#77
12-28-2012, 08:06 PM
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You've given me some direction. Thanks x. It's such an easy sprocket to change and I've got alot of chain adjustment. loosen chain, remove 2 screws, switch sprocket, replace screws, adjust chain, and switch from speed to power. Might try to find a 17t also for maybe another 5mph on top. One of these days I'll have some results to post.
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#79
12-29-2012, 09:18 AM
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520 chain/sprockets have closer spaced links 530 stuff won't seat properly in a 520 or vise versa. The 17 tooth will give more top speed, probably not 5 mph, more likely 3 but it does speed it up.
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#80
12-29-2012, 09:36 AM
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EDIT: I trust Ckau opinion over something I googled on the internet, but, It appears it's just a width difference between the chains. http://answers.yahoo.com/question/in...4074926AAiXoxX
So I guess you could run a 530 cahin and a 520 sprocket? If you change your rear tire size, you have also changed your gearing. Not alot, but a little bit. Also keep in mind as you alter gearing engine RPM will change too. If you gear the kart for more TQ, you have raised the engine RPM at WOT. And if you installed a perfromance CDI that eliminated the rev limiter, you can actually over rev the engine and lead to engine failure. And if you gear it for top speed, you ultimately lower the engine RPM at top speed because you have placed a higher load on the engine amking it work harder. So it increases heat, and may require a carb rejet to help prevent engine failure. So it's not just a simple sprocket swap per say..... Hope i didn't confuse you too much. Last edited by xlint89; 12-30-2012 at 12:00 AM. |
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#81
12-29-2012, 02:38 PM
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After doing a bit of sprocket and chain research it seems to me that the 520 sprocket would be thinner than the 530 chain and the chain would have side to side play. I thought of it like 10 speed too. I figured having a 13t to switch out with my 16t would be for areas where hill climbing and short bursts of speed were required and then use the 16t in areas where speed and WOT was in order. My buggy had a 530 chain on it (took it to local cycle shop and asked) but Im thinking the sprockets are not 530 because the chain has lots of side to side play. I think ill wait till I can get all sprockets and chain new so I know what I have will match. Its not like a cheap Chinese buggy would ever have mismatched parts.....Right??
Thanks for the replies. Last edited by SLESTAK75; 12-29-2012 at 02:40 PM. |
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#82
12-29-2012, 06:48 PM
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Hate to pop your bubble, but you've got that bass ackwards my friend  Big ring at the crank/little at the wheel = top speed and a ton of effort to turn. Little ring up front (crank), big at the wheel = wheelies, rock/vertical climbing etc. Take it from a bmx/mtn bike racer with 25+ years of competition/bike building. For the buggies the engine output shaft and axle sprocket operate on the reverse principal of a bike because the engine has already gone from the variator pulley to the clutch pulley/output shaft sprocket. |
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#85
12-30-2012, 12:04 AM
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Let me first ask you what buggy you have. Sprocket changes do not create more power. All you do with sprocket changes is move your power curve. The buggies come set up from factory for all around performance. Larger axle sprocket or smaller output sprocket will increase low end torque. Going the opposite way will give more top end torque. So no matter which you go you will improve on one end but suffer on the other.These motors were designed for scooters of less then half the weight pushing one wheel and driving one wheel. The only way to make more power is to build the engine to take in more fuel and air and efficiently burn it. The average naturally asperated engine only fills 65% of the cylinder with A/F mixture weather it be a car or ATV or Cycle. To make more power you need to mod the engine to efficiently bring in more A/F above the 65% volume. Now as for the sprocket , a 520 and 530 sprocket or chain has both different width and pitch. Yes you can mix the 2 but you will be constantly changing sprockets and chain on a frequent basis.
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#86
12-30-2012, 06:54 AM
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#87
12-30-2012, 11:41 AM
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 http://www.google.com/url?sa=t&rct=j...,d.dmQ&cad=rja Last edited by SLESTAK75; 12-30-2012 at 11:53 AM. Reason: left one thought out |
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#88
12-31-2012, 02:32 PM
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After taking a caliper to chain and sprocket they are definitely 530. Chain stretch is why I had play. So if I put the 520 sprocket on I would end up with quicker wear due to the thinner sprocket SOOOOOOOOOO. I guess I will see about having one special made. Thanks for the advise.
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#89
01-05-2013, 07:59 AM
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I do believe I know why I have had such a problem finding this sprocket. It is a 16t "reverse" sprocket. It has a 25mm shaft and all the "drive" sprockets I've seen have 20mm shaft. Might try going to the machine shop at the local vocational school and see what they can come up with. If it doesn't work I wont be out anything.
__________________
MXR TrailBender 160R SYC Perf head P&P,Matched intake and exhaust, A12 cam, Orange CDI & coil, Motorio pulley, 115mm Variator and lightweight drive face,11gm Sliders, UNI, modded muffler + 200 horsepower  http://www.youtube.com/watch?v=3hx-hEWl10c I'll take your insults as compliments and blame it on your lack of intelligence. |
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#91
01-05-2013, 02:10 PM
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I might give that a try. I want a 13t and a 19t that will fit so I can change out for different situations. I will see if Tom can help.
__________________
MXR TrailBender 160R SYC Perf head P&P,Matched intake and exhaust, A12 cam, Orange CDI & coil, Motorio pulley, 115mm Variator and lightweight drive face,11gm Sliders, UNI, modded muffler + 200 horsepower http://www.youtube.com/watch?v=3hx-hEWl10c I'll take your insults as compliments and blame it on your lack of intelligence. |
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#92
11-09-2014, 10:16 PM
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Finally got around to getting a WOT run with the new mods installed. My mods are all posted in my sig. All stock CVT Pulled a 32.7 MPH 300' run backed up with a 32 MPH 300' run. Top speed measured 40.2 MPH I finally made it to 40!!!!
__________________
My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#93
11-09-2014, 10:19 PM
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__________________
My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#94
11-10-2014, 07:28 AM
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My biggest gain was the custom cam I had ground. The grind has a 34 deg. overlap so lots of duration. The available performance cams don't come close. I also had to up the carb to a 32mm mikuni slide carb. The down side is I will use a tank of 103 octane fuel in about 2 hours of trail ridding, also when cruising my RPM's are quite high. I need to regear the final drive to bring the rpm's down and give me more top end on the long runs but I have to be careful not to sacrifice too much bottom end.
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#95
11-10-2014, 06:33 PM
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How much was the custom cam?
__________________
My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#96
11-11-2014, 09:07 AM
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Some where in the 200.00 -225.00 range. The hard part is getting the sprocket in line with the cam using a degree wheel and dial indicator since the sprocket on these cams are pressed on.
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#97
11-11-2014, 05:51 PM
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Too much $$ and too much work for me then. Thanks Tom
__________________
My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#98
11-11-2014, 09:19 PM
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Well all the work you will have is installing, I would degree it before selling. The available performance cams will work fine being out as much as 10 degrees. With the amount of overlap this cam has it is much more critical for if out 3 degrees performance will suffer. Before this cam I had a killer engine. After installing the cam which I expected more power but was totally surprised at the added power. I had to get away from the 32mm CV carb and go with the 34mm Mikuni. As I always say the more air and fuel you cram into the cylinder the more power you will get.
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#99
11-12-2014, 07:13 PM
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Are you looking to sell your cam? That's what it kinda sounds like.....
I know about the more air, the better. Funny though, I remember you and another guy trying to convince me the stock carb was best until you went way bigger engine. That was a few years ago though. I too like my Mikuni flat slide. very responsive.
__________________
My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#100
11-13-2014, 06:30 AM
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No I'm not selling my personal cam. Back when I was running the 61mm bore with A8 cam I run the stock carb. I still run the stock carb with the 4 valve head. It was only after I installed the 6mm stroked crank with 62mm bore and large 2 valve head that I went with the 30mm carb. I then had my 62mm bore sleeved to a 63mm and ported the large 2 valve head but still used the 30mm carb. My sons buggy in the meantime we built with a 3mm stroked crank my old 4 valve head, running the stock carb. My next step was to have the cam reground and after installing found I needed a larger carb since the 30mm was not getting things done, so I went to the 32mm pump cv carb. I had to run a 46 pilot and 190 main but it lacked in 2 areas. Accelerating from a dead stop I had a dead spot (hesitation) I could not get rid of and after a WOT run my plug was a light tan. I went with a larger main but only saw my mid range power suffer. This is when I realized my carb needed more CFM's and the fact that I had 34 deg. overlap this made the CV carb obsolete since the slide relies on vacuum to operate the slide would no longer efficiently react to a rapid acceleration. This is when I went with the 34mm Mikuni. A carb is not only chosen from amount of CC's. alone since a carb size is chosen for the amount of air the engine pulls through the venturi. When a carb is too large the negative pressure needed to pull the fuel up through the main jet is not sufficient which is one reason some people run larger mains then others to compensate but efficiency is lost.
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