Hello every one new guy here with questions on my new coolster.
 

Ok my buddies and i are starting to loose interest in our pocket bikes , we are getting to old to be risking limbs any more lol, any way so we started buying go cart buggys this week, we got a tractor supply single seater with a robin 125 cc and we got a 2 seater from craigs list that is a 150 cc electric start and then today i found a coolster on craigs list, its brand new the guys kid never rode it, its 150 cc electric start and air cooled not water cooled. here are my questions, it is a pretty heavy cart and i need it to have more power to make my happy, so have i wasted my money or can i add some ponys to this thing? the type of riding we do is mixed, we do both hill climbs and flat track racing so im looking for all around gains in top speed and low end grunt. i am fluent in modding 49cc pocket bikes and am a car guy so nothing is beyond my scope, i guess a filter and rejet is a must? i dont own a wide band so what jet would i buy with the filter? what other mods are known to add some power and help meet my goals? i read up on the clutch and spring mods but not sure which i would go with to get a little of both worlds, i know its tough to get both high and low end from a clutch and spring kit. im open to all ideas so please be specific with your advice, for example dont tell me to add a air filter and a jet with out telling me which is the best starting point to work from, also last question whats the absolute best site to deal with for ordering stuff for this cart? thanks in advance guys ill be sure to add videos when i get a chance. we just made a video of my 5 hp aspalt cart that i put a nitrous kit on :)

do you have a you tube ??

Very cool name. Wish I had thought of that.

I am assuming you are referring to the Coolster when looking for performance but the following should apply to all 150's.

For more power, based on your description, first thing I would do is go with an air filter. In our track attack vids, there was a marked difference in performance with the UNI. Since your riding styles are mixed, I'd say you could benefit from the clutch mods. Since you do a good mix, I'd actually suggest 13 gram sliders and the yellow rear main spring. I did that once before and was pretty happy with that combo. Going with the 12 gram sliders I was not as happy an on my flat track there were not real gains.

For jetting, it can go many different ways. What I have learned is that different buggies respond in different ways. On these Helix machines, right off the bat with no mods, they like at least a 128 main jet. That doesnt' mean that yours would like that. No one can tell you specifically what jet to get until we know what jet is in it now, and how it responds to jetting. A helix you can move 5 jet sizes and still be within reason on the AFR to where it is not bogging or sputtering. On other machines, I have moved 5 sizes and the machine hated it. The problem is the carbs don't all come from the same manufacturer. Jetting is DEFINATELY a trial and error thing. I own at least one jet in every size from a 128 to a 152 skipping every other one.

As to which vendor, here's how I do it:

Which one is closest to me (thus can get me the product in my hands first)

Which one has it in stock (again thus can get it to me first)

Price.


you'll be fine with either one. Figure out what matters to you.

One thing I will say regarding your entire post is that you MAY find that you wish you had bought a 250. In most cases, the power difference in a 250 is considerable. Check out this vid here where I raced one of my 150's against a 250. (mind you I have driven other 250's that my helix would spank kinroad for example):

dang how do ya ttype so much lol :)

I'm old.

I agree with BuggyMaster is you're going to get
a Buggy, get a 250cc.


The best bang for your Buck is to do
your 150cc CVT first.

Overall Performance: 11g or 12g Dr.Pulley sliders and and Yellow Main Torque Spring

Low End & Climbing Power: 9g or 10g Dr.Pulley slider weights and Yellow Main Torque Spring

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AIR : Uni Filter
Carb: Change to a bigger Main Jet (buy a few for Testing)
Exhaust: Performance Muffler
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Electrical
Performance CDI
Performance Coil
NGK Iridium Spark Plugs

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Trusted Dealers
www.sycpowersports.com

thanks for the replys, i went with the 150 because its what was on craigs list when i was looking, cant i get a big bore jug head kit? or even swap a 250 on it? i also only payed 800 bucks for it and its new so that was a selling point.

They definately make a big bore kit. I do plan on getting one some day and track testing it. Motor swap isn't something straight forward. The mount points are not the same. Not a bad price. Try it out and see how you like it for a while. All I have now are 150's myself. I'm going to upgrade again eventually.

i might look into the basics first the clutch abnd sliders and the uni and jets ect , what kind of MPH gains are seen with these sort of mods? my goal is 40 mph or more.

oh here is a pic i just snapped of it with my pit crew chief behind the wheel
http://i209.photobucket.com/albums/b...e/CIMG1265.jpg

Dude that is really freakey. I just sold the one you see below 3 days ago:

http://www.buggymasters.com/forum/im...coolster/1.jpg

If you are trying to gain top end, go with the 13 gram sliders. With those, I was still able to pull off 40+ mph but when I went with the 12's, I lost at least 3 mph.

Our current 150 (Helix) has the stock clutch pieces. The only mod on it right now I think is the performance CDI and we've had it as fast as 43.6mph gps verified.

The UNI is worth at least 1 mph verified at top end but stronger across the whole power range.

Something else that is a matter of fact is these things get faster as they break in.

has any one ever looked into putting a turbo on these? they make very small turbos for snowmobiles and the like. i wonder if a couple PSI wouldnt wake one of these right up lol. how many mph does the cdi gain yah? whats teh biggest mph gain mod?

UNI Intake, 30mm carburetor kit, and performance exhaust. More power from bottom to top and overall speed boost.

Upside: GREAT power, acceleration.

Downside: $500+

Add in some 13g sliders and a yellow main spring and you've got a nice rig!

A performance CDI should give you more top end - exactly how much depends on whether your stock one has a rev limiter.

Dr Pulley HiT clutches have been known to add 1-3 mph top end and make your buggy run solid no matter whether you're on flat ground or climbing a steep hill.

-Mike

thanks for the info, seems the exhaust pipe is the most money, and being 4 stroke that seems odd since its not like it needs a tuned expansion chamber like a 2 stroke. my buddys and i normally fab our own pipes up. how do i know if i have a stock revlimiter? i cant put it in neutral and rev it and it seems to not have enough power to top out its gearing.

Pretty much the only way to tell if you have a rev limiter for sure is to put a tach on it. If won't rev up to over 7-8k rpms then you probably have a CDI with a limiter in it.

The exhausts are expensive because a) they cost us dealers a small fortune to get (we make VERY little profit on them), and b) the exhaust wholesalers don't have them made in large quantities so they don't get the volume manufacturing discounts. The marketplace just isn't big enough for it.

These are custom fit pipes for the buggies, since the header pipes for scooters won't (usually) work because of the (poor) design of the buggy engine compartments. If we could use the scooter exhaust headers the exhausts would probably be at least $100 less. :(

Just get one of the FMF universal slip ons.

Yes, this will give *some* gain, but consider that you're not really changing the original problem of the stock exhaust: The restrictive header pipe. You're still stuck with that 3/4" ID with a slip-on.

If you're good at header pipe fabrication, then you can certainly make one of your own and get a bigger FMF slip-on (and I would encourage this if you're going the slip-on route!)

Otherwise, the MRP header is almost 1" ID and the Hammerhead Performance exhaust is a bit bigger than that. You're getting 30-50% more flow than a stock header pipe, which can translate into significant gains. :D

When using the stock header with an FMF slip-on, we dealers basically consider that a minimal upgrade, if at all.

my wifes hammerhead 150 has 12 gram sliders, hp cdi, hp coil, uni air filter, mrp exhaust, 128.5 main jet, 38 pilot jet. with my fat butt in it it will top out at 42.4 at 9750 rpm

i got 33 mph today down hill :( it needs help

lol! What's holding it back? Is it topping out on revs or just not enough power to pull it?

power i guess, so tomorrow im ordering parts , so i guess i do the cvt, the cdi and the carb and air filter?

That's a good place to start, and the least expensive by far. If it's top speed you're looking for, don't go below a 12g slider.

i see adjustable and non adjustable cdi, do the non adjustable still advance teh timing or do they just have no revlimits? or is the adjustable one the only one with timing advance? if so would you tune it with no timing light provisions? oh and i saw that i can get a cam shaft that adds more mid range and high rpm is that a good investment?

oh and where can i buy proper shocks for this thing? these OEM ones are just bouncy springs i want a softer and dampened ride.

The non-adjustable ones have a slight timing advance, which is all you really need: I've played with the adjustable ones and moving it too much in any direction (advance or retard the timing) and the buggy starts running very rough - if it stay running at all.

The non-adjustable ones are plug-and-play. No additional tuning required.

The camshafts that will give you more mid-range are the A10-A11 range. The A8 & A9 will lean towards more top end, and anything A12 and above is a significant low end boost.

As for shocks, there really aren't any that are made specifically for the buggies. We generally are cannibalizing them from other vehicles (like yamaha blaster front shocks). On top of that, the real trick is finding some that fit your specific model with a decent price. I'm really not much help on that front. :(

ok i got some parts ordered, lets hope it makes a difference, i got the cdi, coil, plug, variator kit with 13 gram sliders and yellow spring and the teflon coated drum thats also slightly larger, the hammer head pipe and uni filter combo with 127,132,135 jets and a slightly larger 38 jet for the long one, my buggy has a 105 main and 35 long jet in it now. i hope to gain 10mph with all these mods along with a bunch or low and mid range. what do you all think? oh and i also am looking for some blaster shocks mine are 13-14 from eye to eye

i think it might do it

Great choice going with the 13's and the yellow. Best of both worlds. If you have a 109, plop that 127 in there after adding the UNI and see how it does. I've found that some of these with the smaller jets in stock form are very sensitive to just how many sizes up you can go reasonably. These Helix's on the other hand I usually take out the 114 and drop in a 128 or 130 while making no other changes and the machine runs beautifully and along the proper AFR.

Good choice on the CDI. I have consistently gained 2 mph at the very top end with the ones I get. The adjustable one is likely overkill.

Coil and plug are untested with me. I suspect minimal gains but I have been wrong before.

For the teflon coated drum, you mean the bell over the clutch in the rear?

If so, that will be very neat to see how that does. Should provide a little stall effect.

Ahhhh....the shocks. I looked at this just prior to selling my coolster. At about the same time, I had a Baja Reaction. For a pair of rear shocks, with dampners, for that machine brand new it was about $30. They looked like they would bolt right on. What you are up against is in fact being as close to the same eye-2-eye height as possible. Variations from that will throw off you geometry and you may find you are now a low rider or you have a lift kit. I always wanted to find a pair from a HammerHead 250 to put on mine but sold it before I ever had a chance. New shocks could make a TON of difference on those machines.

When dealing with the cam, be careful what you wish for. In the video below, my entire goal was top end. So I got an A-9 cam which is a top end cam. I did in fact gain a few MPH in the top end. However, I lost a lot of useable power in the bottom end. At first I thought it was the FMF slip on but have since learned that it was in fact the cam. If I had had a scooter, that A9 would have been perfect. Not the buggy. Like I said, take a look at this vid of my heavily modded helix vs my completely stock one:

well my stock jet is a 105 not a 109 thats why i got 3 jets to try. not sure on whats teflon coated all i know is i got the kit it has different ramps and is larger so the belt can go higher, it also has different fins for less drag. oh and i measured my shocks they are 14 eye to eye so i just went on ebay and bough 4 yamaha blaster front shocks which are also 14, i will probably just have to narrow down the eyelets.

I had 109 on the brain because the only other one that I have seen with such a small main is the baja reaction I mentioned. It had a 109. I was shocked. I plopped a 114 into it thinking they had it running lean to meet carb requirements and it really hated that 5 size bump. Wound up putting the 109 back in. Of course, this is totally stock.

I see on the variator. Cool on the shocks. I can't wait to see how that comes out. The guys that go with the blaster stuff love em.

well im hoping that 127 ends up small enough, the place i ordered all the stuff from was gonna give me a 130 as the smallest of the 3 but was out of stock so i got the 127, now looking back i probably should have got smaller yet. do you think the pipe and uni will allow me to go all the way up to a 127 from a 105? the plug looks good now.

Ya actually I think you'll be just fine. Both of those two items make a hell of a difference in the air flow. My stock jet on the helix was a 114. With a cam, pipe, and UNI, it took a whopping 150 main jet to get the proper AFR.

its good to hear that the pipe and uni make a big difference, this thing is just to weak for me. i think its rated at 10 hp now, would be nice to get it closer to 15 hp.

I think the only way you will get it to 15 is with a big bore kit. That's on my list of things to test one day. Funindamud had one on his machine but spanked the engine on it. He said that kit provides a lot more thump which is what those heavy coolsters need.

the 155cc big bore that dont need any work done to the block or the much larger ones? and why are these so heavy? it said they are chrome moly, but mans it sheavy, i was gonna try and lighten it if i could.

I don't think there's much umph out of the 155's. I'm talkin about the 180's. I think people use the smaller ones when they have trashed their stock cyliders.

While I'm thinking about it, when you jet that carb, keep to your stock pilot jet (long one) until you have determined that you in fact need to change it. More often than not, people change that and introduce more problems.

what will i look for in determining if i need to use the longer one or not? i cant really read teh plug for that so i guess i look for bog or hesitation?

Exactly.

ok guys parts came today, i will be doing testing on each part, i do have a question, the dr pully variator kit came with 3 washers, it says to use 0-3 washers between the boss and static pulley to get a better match of gear shift ratio and the revolutions of engine when the torque isnt strong enough, so whats the deal? more washers make higher rpm or less washers? i also got the yellow spring to help with more rpms so i dont want to install washers in such a way i might loose top end. basically it changes the length of the boss by using more or less washers, any ideas guys?

The three washers are included because some scooters come with washers that act as spacers between the boss pin and the outside fan plate to allow the belt to sit lower in the variator for more low end.

Most (if not ALL) buggies do not have or require the use of the washers. In your case, since you're looking for top end, do not use them.

ok update on the buggy, all the parts are on, my question is how long do you guys like to run on a set of jetrs before you get a good reading? in a car i normally do a pull and shut the key off and check them, on the buggy i rode aroun dmy yard for about 5 minutes and checked it. is that long enough? with the 127 main and 35 pilot the plug stayed pretty much white, it had a tiny grey or tan starting to form, so u upped it to the 133 and the 38 plilot and rode again for about 5 minutes and its still just barely tan def no black soot. should i ride longer on this or go to the 135 and try it? one thing i noticed was the exhaust pipe was very hot indicating lean when i ran the 127/35 combo and it was much cooler to the touch with the 133/38 combo.
as for performance i can definitely feel a difference around the yard its much snappier, still not enough power for me but we will see how it goes. i made a video showing how to install a cdi box in a coolster and will start a thread on that and post the video here in a few. but let me know what you guys think about the plug reading.

For the plug, you get a new one and then do a long wide open run (my road is 1/2 mile). That's all it took. Give me a sec and I will find the pic of what my plug looked like just from that much.

Look at the attached pic. This is what mine looked like after just a few of those 1/2 mile passes. Very bad. Don't pay attention to the insulator, how's the tip look?

Attached is what it looked like after four months of the proper jetting.

nice pics, yeah im familiar with plug reading, what i just needed to get a idea of is how much of a run these carts take to get a reading. im on the 133/38 combo now and i dont have a long rode like that but i will get to one soon.

Gotchya. Ya it doesn't take much.

update: buggy runs good, still not as powerful as i would like but better then it was. i ended up going to the 135 jet and hit 38mph in about a 1/8th of a mile or less. i had a good wreck to, i was flying across a field full speed and hit a sharp bump that sent the ass end up and over i cartwheeled a few times end over end and landed on my wheels and kept going, my buddy was starting to run to see if i was ok, damage report is not 100% known at this time it was dark out, i do know i broke a fog light, i jammed grass in both front tires beads so they leaked flat, i bent the chain tensioner bolt and mount so the chain started skipping. the right rear wheel wobbles a little not sure if its rim or axle yet, other then that it stayed running and kept going. i think my back might hurt a little in the morning but that sprobably from them super stiff shocks more then the wreck. the roll bars are awesome on this thing i didnt get hurt at all or really feel any discomfort.

Holy cow! Well on the flip side (no pun intended) you did gain quite a bit in MPH! Be sure to post pics! Glad you are ok.

I... uh... take no responsibility for this!!! :)

Dang, man - I'm glad you're OK. This is a testament to the safety of the buggies right there!

Since you're already at 38mph now, you can probably hit that magical 40mph mark with a 30mm carb (once you get the buggy back in good shape, anyway!) A 155cc kit and 30mm carb package with a ported head would probably give you more than enough to hit the 40mph+

Let's see how you feel in the morning. Those kinds of phantom injuries sometimes take a day or two to reveal themselves. You may find more damage in the daylight as well. :(

Sure am glad you're OK.

haha yeah your not responsible , just liable... LOL

any way can i ask a favor of you guys? can you help me find a source for parts for this buggy? i found sites selling the buggy but not parts, i want to locate a source for the typical stuff that bends and breaks like axles, rims , tire rods ball joints ect . that would be a huge help if you guys could see it to help me find some sources.

yeah phantom pains, im all about that, im 36 and have more dirt bike jumps and other stuff from my youth still plaguing me every day. i am pretty sure the wreck was more about the shocks being garbage springs they just dont do anything but bounce and they are super stiff, i got 4 blaster shocks on the way as we speak.

oh and for future reference these coolsters might weigh 500 ibs but im kinda glad its real roll bars and not just thin tubing like on the tractor supply carts.

I'll ask around. I think BIGE might have a lead on that.

And to think you were complaining about the weight just a couple days ago! :D:cool:

Coolster is still in business. www.coolster.com

wonder why google never brought that site up for me, ill call them monday and see if they can get parts.

There are several sites that I forgot to bookmark the first time around (with very obvious names like the Coolster one). When I went to google them, if I didn't pretty much type in the correct URL into google it didn't come up with any result for them.

The search algorithms they use can be pretty screwy sometimes.

google never works to good for me

I hope your fine
maybe your goal "40 MPH" is not a real good idea :)
j/k

ide step it up 2 a whole new buggy

pat...now he'll be shootin for 45! LOL!

5 is like 10 wen your low to the ground

Maybe more like 40mph IN THE DARK IN A FIELD is not a real good idea! :) :eek:

I've hit a few things myself in the dark that I never would have in the day, but I was only going a couple mph, not flat out when it happened.

hey Justin, how's the buggy look in the aftermath?

buggy is good, i been riding the last 2 days , most of my rear wheel wobble was teh large castle nut was loose, the axle is not true 100% but its not bent enough to feel it or even barely see the tire move, it may have been like that when i got it who knows, the rest of the buggy is great, i only have 2 lights on the front now but thats ok, tomorrow i plan on shooting some footage of it in action, 2 of my blaster shocks arrived today so i will put them on tom as well. on a side note.
my buddy has one of those buggys you see at tractor supply with the 6.5 robin motor, we cant find any after market support for it, so we spent the last 2 days making our own mods for it, we disabled the governor, made a custom stinger free flow exhaust for it from a old pocket bike exhaust , made the air filter free flowing, took the carb apart and found it has a 80 jet in it, welll they are much smaller jets then i got for my buggy so we drilled it out to a 95 and are gonna see how the plug reacts to that. we also couldnt stand the bouncy fake shocks, so we took the hood struts off a couple ford taurus and mounted them along side both front shocks and also a mono one in the rear, thsi in affect adds some added rebound force as well as minor dampening affect, it rides so much better now. we also replaced the crappy seat with a ebay racing seat thats very much like the one on mine, the only thing left on our list is a 4 point harness and making the brakes better. we should have footage of that buggy in action tom too, we GPSed his buggy before and after mods and we took it from a stock 29 mph to 34 so we gained 5 mph so far with it, mine only does 38 so his almost keeps up, we also stretched the spring in his tranny to make it perform as if we put a stiffer one in so it holds first gear longer and down shifts faster now as well.

5 mph is a pretty good bump on one of those! Can't wait to hear how much difference the shocks make. Suspension really was the weak spot on the coolster.

today i put the blaster shocks on the front and while still stiffer then i like they are way better then teh fake ones it came with, it has nice soft dampening , the other two shocks came tonight and i will get them on the rear tomorrow. we didnt get any footage today as we spent the entire after noon with the back hoe digging dirt to make jumps and table tops and whoop dee woos for our race track we are making. we spent the remaining evening modifying his brakes to be better and reinforcing my chain tensioner to make it stronger. i hope that tomorrow we can finish the track and get some footage.

how's the new shocks doing? Also, how about the vid?

shocks work good, i relocated the rear perches to make the rear softer yet, vids are coming, i just been super busy. i did shoot a vid friday of me in my honda at the track you can see that here. i had teh mic turned up to far so its sounds bad.
http://www.youtube.com/watch?v=3IzoBNVagjg

sound sucked but nice pass! What are the specs on that thing?

cool vid! bad sound:/

the mic has hiigh and low settings and i never used it before so it was on high, on low it sounds much better. the car is my daily driver civic , makes 510 hp at the wheels on 93 pump gas and 20 psi of boost. best pass ever was a 10.7 at 138

What camera did you use JustinSane?

I'm planning on buying the Vholdr ContourHD
or the Oregon Scientific ATC5K.

Leaning towards the Vholdr more.

im gonna buy one some time too

a buggy vid as promised
http://www.youtube.com/watch?v=F5vCrbhScsc

and the camera is called a gopro its meant for this sort of thing.

my back is sore so i wasnt going full bore in the buggy.

That looks like it runs rather well. Sounds great too. Even more impressive is how well your buddies go kart runs. Great riding area too.

well it wasnt full bore i had to lift allot my back is pretty sore righ tnow, as for his , we made allot of mods to it, we made a exhaust and free flow intake and drilled our own jet and made our own clutch and spring kit for the tranny so it holds low gear much longer. i will get better vids soon as well as vids of the buggys them self.

awesome

great video.

love it

well i was going to look into outing a turbo on my buggy but after speaking to mike i went with a carb kit, the 32 mm carb and intake kit to be exact, this mod should put me well over my 40 mph goal and add some low and mid range power, what do you all think?

Unfortunately, I don't have any experience with going to a bigger carb. Can't wait to see how yours does.

And for the record - it's a 30mm carb. The 32's don't fit the 150cc intake, and if they did, you'd lose most of the benefit anyway because the cylinder intake just isn't big enough to accommodate that much carb (at least without some serious big bore and stroker crank, but that's something else entirely!)

Any news about the back shocks.

yeah the blaster shocks work good, i also relocated the rear mounting point to make it even softer.

Awesome!

well i spent over 12 hours today trying to get this new carb to work, its 2 am and i am just to tired to go any longer, we got it to run but barely and it idles very bad, we arent exactly new to tuning carbs so we are stumped. to get it to even run with out breaking up bad at high rpm i had to put my 105 jet in it, 127 and up just miss badly , the air screw pretty much does nothing infact its the first carb i ever seen that it runs best with the screw all the way in bottomed out, most like around 1-2 turns out. while it wont idle smoothly we did get a speed test in and its actually 1 mph slower then my stock carb. i think i got a defective carb at this point and will call mike in the morning to see what he suggest. there is no reason we shouldnt hav ebeen able to bolt it on and do a little minor jet tuning and go ride, the bad news is we are having some people to come over sunday to ride and now my buggy is all converted throttle cable wise and intake ect for this carb that dont work so unless i get it working some how theres gonna be some bummed out people who wanted to ride. :( sucks mike is across the country aint no way to get a new one any time soon. we did all the basics check the float level, air leaks ect ect we checked every thing a dozen times. we took the carb apart and noticed what looks like unfinished passages for the pilot circuit, perhaps its just a defective carb.

Sometimes it takes a little break from working on something for so long that you lose track of the bigger picture of what could be wrong. I've woken up in the morning many times with a new idea or perspective many times.

To be running a jet that small with the setup you have is just bizarre in terms of it running "best".

I don't see anything in your post about the slow fuel flow from the tank you reported on the phone - anything come of that? Also, nothing about any spark plug readings. Without these, we have no idea where we're at. None.

Also, if the the pilot circuit was messed up, it still would not have anything to do with wide-open. The pilot is not even contributing at that point.

The A/F screw on these is only for very fine tuning and isn't really for adjusting idle or anything. The idle screw doesn't seem to get it where you need the idle to be? Have you tried changing the little clip on the needle inside the slide? This can help with the idle. Move the clip down to richen, up to lean it out. This should only be done to help with the idle and your A/F mix at idle.

Couple last things: You've changed a lot of parts all at the same time, and may or may not have all of them dialed in completely, especially after the rollovers, etc. Did you check for exhaust leaks, too? Are the coil wires/spark plug cap securely attached? Try swapping the coil back to the stock one (with a 130-something jet in the carb, which is where you probably should be running - unless the spark plug says otherwise!!!)

Worst comes to worst, the carb may indeed be defective. But I think there are too many unexplored factors at this point to make that kind of call.

If you do need to call tomorrow (today? :) ), please don't call before 12noon your time (9am here) - the phone won't even be turned on before then. Also, *please* have spark plug data for each of the jet sizes you're trying. I don't want to have to play guessing games and have us both get more frustrated because we're not gathering actual data, just changing random things here and there an possibly getting farther from where it needs to be. There is a process to this, and it goes a lot smoother if we have specific information to point us in the right direction.

The good news: You don't have to take everything completely apart if you want to put the old carb back on. It should fit just fine in the new intake - I tested a stock carb here in the 30mm intake and it'll clamp down just fine. Putting your stock throttle cable back is a bit of a nuisance, but at least you'll be able to ride when your friends are over! :)

I just ran into something like this on my racing kart. The pilot jet worked reverse of normal meaning the mixture screw is actually metering the amount of air. When you turn it all the way in, it is giving it the most amount of fuel which is what it is looking for. If that carb is in fact set up like that, this means the pilot jet is too small (turn screw all the way in and get the most amount of fuel which it likes and which explains why it runs so much better with it turned all the way in vs what you'd expect is it dying all the way in).

wo thats some thin i never knew

If this is what is happening, then adjusting the clip on the needle inside the slide can richen up the idle (that, and/or putting back in the bigger pilot jet that it came with! :) )

I kinda worried and thought about all this overnight and got cruddy sleep trying to figure it all out. I'm just concerned that too many things were being altered at once instead of baby steps (try this, reset back to default, try that, reset, etc). If you keep changing things and getting farther away from the default setting you may inadvertently be contributing to worse performance.

At some point, we've got to go past "mechanic's intuition" and switch over to a calculated "engineer's process" of experiementation.

I'm hoping the reason he hasn't responded yet today is because he got it worked out and is having too much fun in the sun to get to the computer! :) :cool:

Considering how well they got that yellow go kart to run, I feel he'll get it figured out. Probably out running it.

Guys please tell me if I'm wrong

If you screw in the Air/Fuel Mixture Screw all the way
in while idling and the engine does not die, you should go to a
smaller pilot jet. The engine should die before it gets that far in.
Less than 1 turn out, you should go smaller also

The goal is to find the setting that provides the highest and smoothest RPM idle.
Usually between 1 - 3 turns and then your pilot jet is correct.

More than 3 Turns out then you might need a bigger pilot jet.

The typical Fuel Screw settings are in the 1 1/2 to 2 1/2 range.

We had a couple conversations on the phone today, and it looks like there may be a manufacturing defect in the carb as there doesn't seem to be a complete pilot jet circuit.

Maybe the guy whose job it was to drill that hole completely overslept that day and they just kept making them without him. Who knows?

Anyway, I'm sending him a different carb and we'll see how that works out.

lol
.

That all depends on the way the carb is set up. That is why I mentioned my racing kart. Under normal circumstances, as you screw it in, you are cutting off the fuel supply thus leaning it out. If you screw it all the way in, you cut the fuel off completely and it should/will die.

On my racing kart, despite the fact that the mixture screw is on the engine side (which usually dictates that you are adjusting the amount of fuel as explained above) it was backwards and I haven't seen many like this. In this case you are adjusting the amount of air allowed to bleed into the fuel stream. If you close it all the way you are not cutting off the fuel, just the amount of air going into the stream. Close it all the way and you have a solid stream of fuel (which gets mixed with air through the air intake of the carb). The fact that justin can turn it all the way in and it not die makes me think that it is possibly setup like my racing kart. This of course is all theory without having my hands on the carb itself.

yea i agree with em

ok guys update... we tore the carb down and went threw every passage and circuit, here is what we found, the choke assembly fits very poor and is actually allowing air to go unmetered past the shaft and into the carb, basically a small vacuum leak, i took the choke apart and put a o ring on the shaft and it stopped drawing air there and the idle improved a bunch but still not correct. next we got rid of the riser section of the manifold and mounted the carb directly to the head with the metal elbow, this greatly improved how the cart runs making me think that the long riser is some how ruining the signal between the motor and the carb. so with the choke leak fixed and the carb mounted to the elbow over all running performance improved a whopping 80% almost as good as stock,even the idle screw started working properly, while the air screw still was almost not working still. i drove the cart and it ran pretty good it even allowed me to go back up as high as the 127 jet before it started running like crap at WOT. i pretty much got fed up at that point as i had almost 24 hours of working on teh cart at that point so i ripped all the new intake and carb and throttle cable off and went all back to stock. i would hav eliked to use the new metal elbow with my stock carb since we did port the head to match but that placed my carb right into a cross bar and wouldnt allow it so all stock it is for now. i was going to drill out the passage that looks unfinished but i left my small bit at home and said heck with it the new carb thats on the way will use my stock cable any way so might as well revert back so i can at least ride sunday. i only hope i can figure a way to install the new carb using some of the new parts i payed for so i dont feel like i wasted my money lol. any way as far as performance gain with any of the new carb parts , there wasnt any it lost 1 mph , granted it wasnt working right but i still did MPH test just to see where it stood. my hopes are the new carb lets me feel and see some gain to justify the money im putting into it , because while the OEM carb and intake only does 39 mph , it startes and idles every time and runs like a champ :) i hope i gain a few more MPH cause aint nothing worse then throwing a few hundred bucks into something to stay the same or worse yet loose performance hahah :) thanks to mike for all the help and good customer service, i have a feeling if he lived closer he would have driven over to help.

Great info. Were there physical issues with the idle circuit that you could see?

How is that carb set up? Is the mixture screw metering fuel or air?

the circuit appears to not be finished, as for the metering it appears to be set up to meter air past the needle to control how much fuel would in turn be drawn up and into the circuit, however the hole to allow it to enter into the carb is not drilled out all the way. its almost like they just forgot to do it or its not part of this particular models features. i dont know.