Will this work?

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sxpimpin

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So I'm 18 and money can't really be spent on the go kart ive been messing with lately. The kart itself has 16 turf tires on the back and 12 inche nobbies on the front. Engine is a honda gx340 10 horse power key start and has 1 inch shaft. There is a 5/8 inch jackshaft going to a 72T sprocket. Now seeing that I'm trying to be as cheap as possible I bought a 5/8 hilliard extreme duty centrifical(up to 10 horse power) clutch to mount to the jack shaft and i want to put a regualar 1 inch drive sprocked on the motor. Say i put a 40 tooth sprocket on the motor going to a 12 on the clutch which spins another 12T sprocket located on the other side which going to the 72T sprocket... Will this work out or am i gonna smoke the clutch? i know low rpm is bad for clutches but the larger sprocket on the engine is only gonna spin that faster. Can anyone figure out the overall gear ratio?
 

AdrianH

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If I get this correct, 40 teeth on the engine shaft to 12 teeth on the clutch will mean that for every 1000 revs of the engine the clutch will be doing 3333 revs.

As clutches will try to bind and transfer power at around 1500 revs, you need a tick over of less then 400-500 rpm on the engine.

The 12 teeth on one side of the clutch will drive another 12 Teeth on the shaft up to 72 teeth on the axle will give an overall 0.55 reduction with the 40 T on the engine shaft. So when the engine is trying to run at 2000 the axle will be at 1,110 rpm. With 16 inch diameter tire that would be trying to propel you at approx 52 mph. Assuming I got all the maths correct.

I think you would be better with, say a 20 teeth sprocket on the engine, that way you would have a better rev range and more control over acceleration and more pulling power.

Hope it helps

Adrian
 

sxpimpin

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Thanks alot man that does help.

Do you know where I can find a 1 inch drive sprocket with that many teeth or possibly less? I've only been able to find 5/8 and 3/4, so my only option i thought would to get a 1inch sprocket hub for live axle and mount it to the engine with the smallest sprocket I could get-40 is about as small as ive seen..
 

mikeandike

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On your jackshaft, the way you explained it is wrong. You would want to put the clutch driving the axel and the drive sproket on the engine driving the other sproket on the jackshaft.

If you used a 40 tooth sproket on the engine 12 tooth on the jackshaft like AdrianH said it would be spinning 3333 rpm. Most clutches engage a 2200 rpm so the clutch would become useless
 
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RobertD

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i'd do a 1 to 1 sprocket between the engine and the shaft since your clutch is going to be on the jackshaft. They're made to engage at a specific RPM, and if you're using a 40 to 20 (or whatever) then it will change the RPMS... That's not necessarily a problem (if the clutch was on the engine), but because you've got a clutch in the mix I would think it would be a problem.
 

RobertD

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also I've bought a 1" 12 tooth clutch from norhtern before -- it was 50-60 bucks as I recall. You might buy that and put it on the engine.
 
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