Seriously

Joined
May 28, 2019
Messages
137
Yo do I got this 3hp Briggs and Stratton m putting on my bike yes it's a 4 stroke... My question is if I get a centrifugal clutch like what's on a minibike or go cart let's say 11 tooth would that work ? Incase it matters my back wheel is 26 inch with 36 tooth sprocket ..
 


The_Aleman

Well-Known Member
Joined
May 2, 2007
Messages
1,010
Yeah, def wrong section. Anyway, you're gonna need more reduction to make it work. That's what those bolt-on jackshafts do.

Otherwise:
NoReduction.jpg


You'll burn up the clutch trying to get anywhere.

Edit: fixed image
 
Last edited:

CrazyDan

Well-Known Member
Joined
Jul 9, 2016
Messages
2,274
I had a friend have me help out his son with a build, the moron tried to run a 10t to a 44t, no other reduction on a 26" bike... with a 35cc honda weedwacker motor :ROFLMAO:. He wondered why it didn't help for sh*t when he gave it full throttle. At that steep ass gear ratio it was geared to go 123 mph at 7k rpm with just 1.63 hp. It takes roughly 4 hp to go 55 mph if you tuck hard against the wind, over 5 if sitting up.
 

LewieBike

Active Member
Joined
May 21, 2014
Messages
659
You'll need at least the 79cc conversion kit gearing. Those B&S 3.5 hp engines aren't really designed to run much faster than 4.5K and they're all of about 120cc's Seriously, if you don't have the tools or experience in making up a from scratch engine drive system you're gonna have a hard go with it.

For about $90, Amazon has this all in one 49cc 2 cycle weedeater engine and gearbox that would be easier to make into a bike drive than starting from scratch with a used B&S. https://www.amazon.com/dp/B07QVCNF85/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B07QVCNF85&pd_rd_w=0Ij9l&pf_rd_p=45a72588-80f7-4414-9851-786f6c16d42b&pd_rd_wg=JheGq&pf_rd_r=JMR7WC1F27MG7T50GTKV&pd_rd_r=3f583b56-fe73-497d-880c-fcdecc25c261&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFVOTFCNFlDREhLNlgmZW5jcnlwdGVkSWQ9QTAwMjEzOTMyVEtIWFRMSThHVDkmZW5jcnlwdGVkQWRJZD1BMDg1NzM3MTEwNEVOTFQxT05BQUwmd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl
 
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