Engine choice -- need input

[x-bird]

I hate to open a new thread for this, but i really need to make up my mind and pick an engine option for my yerf. I intend to stick with the 30-series TC setup and want to be in the 8-10 hp range with electric start. So far my options are the following:

Lifan 9 hp, about $330 shipped
LCT (China) 9hp, a little cheaper than above
Blue Max GX 9hp clone, about the same as above
Subaru Robin 9hp, about $600
GY-6 type 150 or 250--- ????

Of the basic horizontals, the Subaru wins hands down on quality and support (hot rod parts are slowly coming), but the price is just killing me.

I'm pretty sold on the Lifan over the LCT or Blue max. Lifan has some minimal support and a few hot rod parts here and there, but at least it looks like a well-established company with a reliable engine for a decent price.

A GY-6 type. These things are a big unknown to me. A lot i see for sale that don't have a carb on them. I know they're used on buggies, but do they work with a 30 series TC or am I into a complete re-fabrication session on the back end to make one work? Pricing seems all over the place and I don't know which "type" to purchase for a kart. If it's an easy install that doesn't require a lot of extra components and can be had in the $400 range, then i'd go for it. I don't mind fabbing frame parts/mounts etc, but if i have to do new axle, sprockets, TC etc., then it's likely a no go.

Any and all input welcome. TIA

[xlint89]

How about the new 13HP "predator" (Honda clone) from harbor freight?

http://www.harborfreight.com/predato...nia-68306.html

The Blu Max wasn't real good, so they switched to this one.

I installed the 6.5 HP on my Yerf 3203 and have 0 issues with it. Starts in 2 pulls or less.

Lots of aftermarket parts available if you wanna beef it up even more.

Also, HF has a 25% off coupon floating around for New Years Day only.

Or 20% off anytime you're ready.

http://www.ebay.com/itm/Harbor-Freig...item336ff46c0c

As for the GY6, that's all a self contained engine and transmission. Your TAV will not work with it. The engine mounting is WAY different. Would take alot to switch over IMO.

If you search Youtube, there's a guy that has the 13 HP Honda installed on his 3203 already.

[x-bird]

I've already noticed that the pricing on the 13 and 15 hp clones is pretty attractive. For all of $20-40 more than a 9hp i'd get the bigger engine, but my concern is whether or not the 30 series torque convertor would hold up to it. I think all of my options require a new clutch/driver as the 6.5 tec has the 3/4 shaft and everything 9hp and up appears to use the 1 inch shaft.

When it comes to the GY6 150/250s, I'm assuming that i would just need a chain and axle sprocket? (She needs a new sprockets and chain anyway)

I can deal with fabbing up mounts. Very soon I expect to extend the back end of the yerf to get more travel. (I have some used Fox shocks headed my way) The issue of adding a battery isn't one as I'll have to do that for whichever engine I add.

The GY6s just seem to be require more "fiddly" attention to them to get them dialed in. Is this true or just my imagination at work?

The other issue with them is that I think after buying the engine itself I still need exhaust and possibly other parts. Axle???? I'm having a hard time pinning down the cost of putting one in.

I've been looking at some of the threads, but i have yet to see a really good picture of one being mounted in a "bare" state to get a good idea of how it sets in relation to the chassis and axle. What is putting me off of them is i have the mental picture that they sort of work like a motorcycle swingarm. If i wa ready to commit to an IRS fabrication session, it'd be a no brainer.
Are they all like that or is there a particular version that the transmission is fixed so they operate driving a fixed live axle setup?

This is a pretty big deal for me expense wise and I want to get something that meets my goals the most affordable way. fab work that can be done from my metal "stockpile" doesn't bother me.

"Goals" --
Budget-- about $400-500 total
Power-- 9hp to 15hp max
Parts/reliability --must have support for stock replacement with some room for modding.

[joekd]

I have a stage 2 clone from these guys http://nr-racing.com/Clones.htm

Motor has been a perfect idle and pulls strong since the first start, was on my son's yerf but was a little too much for him so I pulled it off and replaced it with an electric start 6.5 motor

Ended up putting it on my trail bike with a comet TAV 30, to say the least it's a wild ride

Here is a vid of it running, I have since then replaced the header with a much better one

http://youtu.be/kG3sEdGg6u4

[Bootboy1488]

my helix is in my friends garage x-bird, i should be over there finishing up getting it running next weekend ill take a bunch of pictures if you haven't made your decision by then. sorry it couldn't be sooner

[metalstudman1]

The GY6 doesn't require near the fiddling that a horizontal does!!! most of the failures with the GY6 is simple- turn the gas off and run the carb out of fuel when it's going to be parked for more than 2 months. Also the CVT is far superior to the Comet system and it's enclosed- The biggest advantage is "WHEEL SPEED"(rpm's). The GY6 only has 2 mounting points- 1 over the center top of the engine (near the carb) and the other is at the rear that allows for chain adjustment, it hangs in the frame. The rear sprocket will allow for the chain to go forward,down and rearward directions, so if it's long on the swingarm it can get back to the axle. I've seen many ad's for these in the $330. range with every thing but the sprocket ($20.), so you'd need an axle sprocket,sprocket carrier,#520/530 chain,exhaust and an ignition switch. You can't get me to use a horizontal lawnmower style engine anymore on a kart or buggy because of the endless maintenance that engine brings!!! For me it's a "no brainer".

[x-bird]

Originally Posted by metalstudman1

The GY6 only has 2 mounting points- 1 over the center top of the engine (near the carb) and the other is at the rear that allows for chain adjustment, it hangs in the frame. The rear sprocket will allow for the chain to go forward,down and rearward directions, so if it's long on the swingarm it can get back to the axle.

Thanks guys, this is the kind of input I'm after. I'd like to do something with the engine in the next two weeks, so a bit of a wait isn't an issue. I just need to come up with a plan so I can decide what to do with the 6.5 i have and the little one's mini shark. Even if i replace the driven and shelve the 6.5 for now and start her with the 3 hp and a centrifugal, i'm ahead of the game having a spare engine and "trans."

Metal, what i visualize from your description is that the "right" GY6 for a kart can go in a frame that has a rigid axle attached to it? That's where i'm lost with these, i can't figure out if the "transmission/driven sprocket" portion has a pivot like a swingarm that is going to require a floating axle or a chain tensioner system.

I also gather that 150cc versions of these start out with around 8-10 hp? I watched the comparison and saw that the 250 really just has a stronger bottom to the power band (comes with teh cubes) up top it looks like they're pretty even. I'm a big cube, long stroke torque junkie if you haven't figured that out yet (comes with being a Pontiac guy). ))

I think my perception of "fiddly" seems to come from just the amount that are out there and the no start issues caused by old gas and bad wiring connection--that and apparently there's a lot of adjustment that can be done with the CVT--is that where the variator and rollers/sliders etc come in to play????

BTW, I also have an old, but never used Peterbuilt fog/driving light set-- 2 55 watt lights, relay, switch and harness. Is there a particular amp output level i should look for?

[metalstudman1]

GY6 comes in 2 versions- long & short case.The GY6 needs a solid axle, the engine is the chain tensioner- transmission is in the case, there are different types of reverse-but they mount to or come in the case. Just for info's sake- A stock CVT set-up in the GY6 will last for years "un-touched" if it isn't abused, where'as a Comet style CVT requires dry lube & cleaning about every 20 hrs and is exposed to the elements causing pre-mature failure or wore out belts. I've run a GY6 for more than 500 hrs without any maintenance other than an oil change, Dirt/mud is the biggest culprit to the electrical system. 70 watts is about all the output on a GY6 without damaging the stator or regulator.You are correct about the HP rating, Again the biggest difference is the rpm range and the wheel speed it developes. Either type engine can have issues- the carbs on the GY6 are excellent in comparison when it comes to auto choke/fuel enrichment valve and tunability.Hope this helps a little more- I'd go take some pic's of a GY6 in a buggy but all mine are ATV type now!

[x-bird]

Well, i think I'm sold on the GY6. I looked around for pricing etc. for new, then e-bay and CL for used. New left me feelign like it was still a gamble with chinese mass production. Just spoke with a guy who has a GY6 out of an '05 Carter, complete with wiring, switches, carb, battery, exhaust, needs the solenoid replaced, but he has a new one coming along with a trans cover gasket and the new parts go with the deal. It has an 8-pole stator, which he indicated will handle the lighting i have. If not, an 11 pole should do the trick for that. He also has what amounts to a spiderbox rear end setup mostly new parts not installed. Picking the whole thing up for $550. A little over my budget, but I had an axle and rear frame upgrade planned in the works and a heck of a deal to boot. I'm thinking of taking my complete rear platform and engine moving it over to the Mini shark. I'm already widening the front suspension on the mini, this will widen the rear out and it'll be nice and stable and will advance that project way faster than i'd hoped for.

[x-bird]

I'm going to be talking with the seller again tomorrow morning;
I've seen posts here regarding what I guess is an older, not so well supported version of the GY6 I think. From what I gather the easiest way to spot the better units are by the number of valve cover/head bolts 2 vs 4 ????

I'm still weighing the idea of used vs new. getting all the extras with the used one is nice, will likely save me 2-4 days installation time. Just hoping that I won't be rebuilding the thing after only a few hours of run time.
New On e-bay;

These "scare" me a little as to quality
http://www.ebay.com/itm/150638740163...84.m1423.l2649

The Lifan looks like a much better product
http://www.ebay.com/itm/LIFAN-150CC-...item27c10f2d34

[metalstudman1]

The Lifan is a big brand name- the built in reverse is awesome and that's a very good price. The other is a good looking one too. 4 bolt valve cover is the bigger valves.

[xlint89]

Internal gearing is different between manufacturers too.

I know the Howhit GY6 (yerf dog) is supposed to be geared for low end torque and comes with the larger valved heads from the factory. BUT, doesn't have reverse. (except aftermarket add on)

[x-bird]

Still on the fence with New Lifan vs Used GY6--anyone know which company an '05 Talon GY6 is made by???

The worst part is, there are 2-3 spiderboxes on CL within 2 hours of me in the 500-800 range. 1 is pretty rough at 650, the other 2 i could probably get for 700-750 and in much better shape. While I'm tempted by them, I'm also wondering if I'd be wading into the deep end of the money pit and end up abandoning everything I've put into my little piece of metal mayhem.

Used .... For $550 i'd be getting a running GY6 with the wiring harness, exhaust and battery, extra jets, new TC cover gasket and a new starter solenoid (present one isn't working) along with:

"BRAND NEW PARTS: (NEVER ASSEMBLED OR USED AT ALL)
(pictured)Axle, axle bearings, brake rotor, sprocket, hubs, tires and wheels(rear)
(not pictured): brake caliper, master cylinder, reservoir, lines-all BRAND NEW

USED, IN GREAT CONDITION:
Swingarm(engine cradle) "

SOOOO, Lifan,+ Carb + exhaust + battery + switches + new sprocket & chain (my slightly bent axle really should be replaced too) +fab work

China GY6, + all of the above less carb

"Running" or barely so 3206/9 for 650-750 .... +??????

[x-bird]

Used with new yerf parts it shall be. It's an external reverse, 4-bolt 2-valve headed, short case GY6. Heading down philly way in an hour or so ...
All of these used Yerf 03s and 06/09s I keep coming across are giving me ideas of a home based "restoration and sales" business.

[x-bird]

Two engines for about the price of one. Picked up another gy6 within a 15 minute drive of the first for $90. needs a new CDI and has been through the wringer a bit. The first one turned out to be a 2-bolt valve cover, but I picked it up anyway. I figure between the two i'll get one reliable engine.

[drillpvt]

I found a gy6 down here in Fl No carb , no starter ! guy owns a scooter shop in Ft Myers , says its new , cam off a new scooter that was wreck in shipping ! no hours on it but strp parts off it ! 200.oo bucks . The scooter motors have a longer trans case right ?

[x-bird]

usually they have the longer case and there are also a variety of different length/machined output shafts on them.