A few Go Kart Questions


Old 05-18-04, 06:42 AM
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A few Go Kart Questions

I am building a go kart currently and on one lucky garbage nite found an 8hp tecumseh snowblower gave it a few pulls and it turned right over. Beautiful engine just gotta clean it up and it will be good as new.

My questions are
1. I am planning on running a centrifugal clutch with I think 12 teeth what is a good number of teeth for the axle sprocket for both decent pickup and good top speed. I have a drive ratio page here but i dont know which one I should go for http://www.mxk.com/ratio.htm

2. I have been reading about headers on this site and am interested in maybe boosting the hp of the engine I have. Right now it has one of those small square mufflers that can be seen in the picture. Is there any company that I can get a header off of, or is it something Id have to make myself. Are there any tutorials for building a header correctly???

3. When revving to what seems like full throttle and letting it out sometimes I will receive a backfire and a ball of fire will shoot out of the muffler. My fried said this is due to the sparkplug is this true.... Is it bad for the engine when this happens.... should I limit the throttlr before this backfire point?

Thank you and I will be posting pics of the build as I go along on my website.

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Old 05-21-04, 01:13 PM
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Exclamation Take a look at Diy Den for diy kart building

Diy Den has good info and plans for the home constructor
Old 06-01-04, 04:31 PM
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Location: NC, USA
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You should be able to make a pretty fast go-cart out of the 8hp engine especially if you want to tinker with it.

Your driven (axel) sprocket size will depend on several things:

What will be the max. rpm for your engine. Are you removing the rev. limiter?

Is your clutch adjustable (can you take it apart)? Most centrifugal clutches engagement rpm can be adjusted by changing the weights/shoes and springs.

Headers are magic. They have no moving parts and can really give you some power. Generally a longer small diameter pipe will give better low end pull but is weaker at high rpm's. A larger diameter shorter pipe is often better for high rpm's. To see some of these differences you will need to remove the rev limiter and turn the engine up around 6'000 - 7'000 rpm's.

Backfiring after reving can have a few causes. You may have a bad exhaust gasket (between the engine and muffler). The carb. could use some adjusting. The ignition timing may be advanced a bit too far for the fuel & cam you have. ---- Be very careful reving an engine without the rev limiter. The engine can rev all the way up to the point it blows. It's easy to tach it too high and break the connecting rod (generally around 7'000 rpm). At high rpm's a cast flywheel can come apart (and take your head off). Usually a stock cast connecting rod will break first and poke a hole through the side of the engine case.

Have fun....

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