Yerf-Dog Go-Kart #3208 gearing/clutch help

[CrispyBooger]

Hi yall hope all is well! i have bought this yerf dog kart from a friend for cheap since the engine locked up for low oil. I have done some changes to it. I centered the steering column as i didnt want to be giving rides lol and i got ahold of a Honda gx390 for cheap to; its huge compared to what it had but i am moving the mounting plate to the side to make it work. Now it has stock tires 20x10-8 and a 60T sprocket i dont know what size clutch to get. I want some speed im 200lbs.

 

[OzFab]

What size clutch was on the old engine? What size chain does it use?

A 60t sprocket seems small for 20" tyres but, I suppose it worked at some stage...

 

[CrispyBooger]

the old engine was a 5.5 b&s it had a comet 30 series torque convertor 3/4 bore i think and doesnt fit the honda shaft. and the chain is 40

 

[OzFab]

No, it won't, the gx390 has a 1" shaft IIRC.

The ideal solution is a 40 series (or higher) CVT but, they can be pricey. With big tyres, lots of power & a 60t sprocket, that's what I'd be doing.

 

[CrispyBooger]

yeah ive seen the prices so im looking for a clutch instead any advice on that

 

[landuse]

yeah ive seen the prices so im looking for a clutch instead any advice on that

A 1" bore clutch is going to cost you about $100-$120. I would gear it crazy low for the size tyres that you have on there. You will probably have to use a jackshaft to get the gear reduction that you are going to need. I would gear at least 9 or 10:1 with your tyres. This means if you have a direct connection between clutch and axle, you will need an axle sprocket of approximately 100T. You will definately have some clearance issues.

This means that a jackshaft is needed. With the cost of buying/manufacturing a jackshaft, getting extra sprockets etc (as well as the cost of the cent clutch), you might as well buy the 40 series TC.

Otherwise, ditch the large tyres....