Just scored an older go kart with a f1 body- I want to put my gx390 on it.

[AKMIKE]

Bought it off the local classifieds. Looking for a clutch that will handle the gx390 and me (250lbs). The tires are 7-8” tall, I think it’s a 60t sprocket.

Upon further inspection the cart f1 body says “bird” and “dr pepper” on a label on the underside of the fiber glass body. It’s also a 1 wheel drive cart.

I’d like to put the 390 on and build live axle for it. My kid will mostly drive it but I’ll play a little also.
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Heres another pic
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Anybody know what size this motor is ?
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I just went checked the sprocket tooth count- 12 on the old clutch/motor, 72 on the other sprocket. What tooth count centrifugal clutch will work well with the 72t and the gx390 ?

 

[Budget GoKart]

Its a 3.5hp or 5hp briggs it looks like

 

[Hellion]

It’s a Tecumseh flathead.

Read us the letters/numbers stamped into the top or side of the engine cover—the engine size/horsepower rating is usually in that code.

I’d run it as-is. One wheel drive, kids don’t need more, plus it will be kept original.

 

[itsid]

very likely five yes maybe briggs, maybe tecumseh.

Well you shouldn't really put the 390 on there..
it being a one wheel peel you'll just shred the driven wheel in no time, without adding much to the fun.

if it IS a five horse briggs it's quite torqey and I wouldn't say there's demand for more torque,
since that kart isn't meant to take adult riders anyways (that body is a bit small to comfortably fit in.. especially if you have a bit of extra to carry around)

And while you could drop the ratio (from now 6:1 to ~5:1) if you were to install a gx390
-say by installing a 14T #35 clutch-,
you would still need a live axle to make use of the extra oomph and not just shred the driven wheel
(which is certainly NOT 7" or 8" tall.. more like 10 to 11" [likely the latter])

'sid

 

[karl]

Y'all can't Id a h series Tecumseh? Shame , least hellion is in the ballpark

On top of the shroud , the model should start with H , with the hp after, h50 =5hp, h60 =6 ,etc

 

[AKMIKE]

Tires are 11” , found the number on the shroud

 

[Hellion]

Yep, 5 HP Tecumseh. Good score.

Y'all can't Id a h series Tecumseh?...

Can’t you positively ID it? Come on now, don’t hold yourself back. You could’ve saved the OP lots of time and effort.

You can’t blame Sid, he’s German and not the sharpest tool in the drawer.
Juuussst kidding.

 

[AKMIKE]

I’m not complete helpless or lazy but I am a little ashamed on guessing the tire size ... I use a tape measure everyday at work but I had been moving truck tires around my shop earlier that day so maybe that’s why I thought they were so small.

Would it be to much of a shame to covert it to a live axle ? My 8 year old races his 90cc quad so I think he could handle the gx390. I would feel bad modifying a vintage kart

 

[Hellion]

Oh idk, it’s fine to modify it. I think the body is ruined already; isn’t it repainted?

About converting to live axle—are you prepared to do the work? Can you do the work yourself?

 

[karl]

Can’t you positively ID it?

I did. correctly. There are no external diffrences between the diffrent HP medium frame engines. Hence why he had to read the shroud

Im just joking around, in good spirit

 

[Budget GoKart]

Honestly i would live axel swap it. Its rare but they are not extreamly rare so i wouldnt worry about it too much plus i would go for something smaller than a gx390 but thats your choice not mine. Just make sure to reinforce the frame a bit.

 

[AKMIKE]

Oh idk, it’s fine to modify it. I think the body is ruined already; isn’t it repainted?

About converting to live axle—are you prepared to do the work? Can you do the work yourself?

Oh yes. I live in an aluminum boat repair shop, rebuild diesel truck transmissions, turbos, engines- and that’s what I do for fun/side work. During my 6 day work weeks I do hospital remodels, airport hangars, schools. But I only own an old Lincoln 225 ideal arc and a gas setup as far as welders go.

I can’t decide between a comet style or noram. Trying to stay low budget for at least a month

 

[Hellion]

A basic run of the mill centrifugal clutch would suffice. Maybe a Max-Torque brand (USA).

Your GX390 won’t exactly churn out mind blowing power so you’re basically overthinking the transmission part.

Your current gear ratio sounds fine for the kart as-is.

 

[AKMIKE]

Cool. What’s a budget live axle conversion cost ? Shipping to AK can be expensive so anything I can source locally would be a plus as far as piecing one together . My buddy has a mill and lathe if that would be useful for cutting the ends of a shaft

 

[itsid]

You can’t blame Sid, he’s German and not the sharpest tool in the drawer.
Juuussst kidding.

...blunt and heavy hitting like a hammer!

'sid

 

[Hellion]

Cool. What’s a budget live axle conversion cost ? Shipping to AK can be expensive so anything I can source locally would be a plus as far as piecing one together . My buddy has a mill and lathe if that would be useful for cutting the ends of a shaft

Some people use what is called a pillow block bearing (basically a bearing hanger) to support a live axle shaft but those are industrial-grade and a lot of them are cast iron. They work though.

I prefer the flat steel (1/4”+/- thick) bearing hangers typically designed for karts and powered vehicles.
Something like this: https://www.gopowersports.com/3-hole-axle-bearing-kit/

Not telling you to buy from Go Power Sports but they are a decent vendor. You can get a piece from here and a piece from there or all in one like this:
https://www.gopowersports.com/live-axle-kit-complete-38-axle-145-70/

Those are just examples. I don’t even know what direction you’re going to go with the kart (keep the slicks, go for top-end speed, run on hard surfaces or no) and I don’t like guessing.

 

[Joe-405]

Those were promotional and giveaway karts......

 

[Hellion]

Problem is, most everything that was domestically manufactured (USA) is now vintage or old/old school. So you might actually feel trepidation at “modifying a vintage kart”. I know what you’re thinking though—is it really vintage? Who gets to define what “vintage” means anyway?


The USA doesn’t make go karts anymore, at least complete ready-to-run go karts (there’s kits of course). Everything else is imported, to include those things pretending to be go karts (Chinese buggies) and a few that really are (Tyrods, etc). So a USA-made Kart is a rare bird already.

 

[AKMIKE]

Some people use what is called a pillow block bearing (basically a bearing hanger) to support a live axle shaft but those are industrial-grade and a lot of them are cast iron. They work though.

I prefer the flat steel (1/4”+/- thick) bearing hangers typically designed for karts and powered vehicles.
Something like this: https://www.gopowersports.com/3-hole-axle-bearing-kit/

Not telling you to buy from Go Power Sports but they are a decent vendor. You can get a piece from here and a piece from there or all in one like this:
https://www.gopowersports.com/live-axle-kit-complete-38-axle-145-70/

Those are just examples. I don’t even know what direction you’re going to go with the kart (keep the slicks, go for top-end speed, run on hard surfaces or no) and I don’t like guessing.

I like the slicks , but going a hair larger on the rear tires would be a possibility with a live axle and converter setup.

At the same time maybe I’ll just copy the steering/spindles and build a little beefier kart for the 390 and just leave this one be. I fixed the brake and hit 25 mph with it wound up. It hits 20 pretty quick as the iPhone gps shows

 

[Hellion]

Yeah those slicks and the low stance on the frame looks bad arse.

Are you planning to use and retain the F1 body? That would be fun and it might actually help with aerodynamics.