gear ratio for non-pedaling start

[AussieSteve]

Gear ratios calculate like this:

Engine has 83t/20t = 4.15:1 internal gears

36t/10t = 3.6:1

3.6 X 4.15 = 14.94:1

50t/10t = 5:1

5 X 4.15 = 20.75:1

Just so you know.

One minor correction. The clutch gear has 82 teeth, not 83, making the internal ratio 4.1:1

For drive-train calculations, this tool is invaluable:-
jpilot's Gear Ratio Calculator.

 

[skrufryder]

Hey guys

Y not use a pull starter. I have them on all my bikes no peddals. I can roll mine a foot or to dump the clutch twist the throttle wide open then take off easly. but the pull starters work awesome. My motors are well modified. Ported and polished. custom intake manifold custom exaust "the race carb" with much bigger jets and atomizers, high compresion head -polished, billit aluminum high comp piston, high comp rings, heavier gage wire, and high out put cdi and cable and a tri fire plug. so it fires realy easy. mine will ride about 50mph with the standard 10 tooth and whay 44 46 tooth rear sproket. I am in the process of making a jack shaft to run a 5 or 7 speed.

 

[blckwlfny1]

*sigh*
Never mind

 

[Bradley wilson]

Hey, I am a big dude too and want to put this 6 hp on my 26' bike. What gear do you recommend with a 10 tooth clutch?

 

[KCvale]

Im trying to fabricate a mid-drive transmission (to preserve the coaster brake as well as the vintage left-hand-chain drive) and i will be trying to shoehorn sprockets into some tight spaces so i have to design it baed upon the size of the components.

You can re-invent the wheel if you like.
Personally I like to do wheelies off the line and 45mph.

http://kcsbikes.com/bPics/2_GT2-GT5-2sFrontLeft1280.jpg

Shift kits are the bomb if you have mechanical skills.

 

[rwaterman00]

26 inch bike -170lbs rider weight 66 cc 40mm motor port matched w a 1inch header expansion chamber with 16mm keihin clone carb 7cc head, 56 tooth sprocket. I can easy pull out from a dead stop without peddling. I can pull out no peddles from a dead stop on a fairly steep hill. the 56 tooth gives me aprox. 30mph in the flat and one can ride fire trails and off road stuff. just weighing in on non peddling start... I don't know gear ratios and the math stuff just real world application
same bike as above with 44 tooth will pull out without peddles but clutch must b feathered
20 inch bike stock 50cc 44 tooth top speed 27mph will do wheelies and take off from underneath you if you put your feet down on wheelies pulls out from dead stop no problem

 

[crassius]

seen similar results as above several times on customer bikes

 

[KCvale]

seen similar results as above several times on customer bikes

Ya, it's fun to build them ;-}

This customer wanted a single speed mountain goat so bought boxes of cool parts and hired me to put them together.

That was a wellie crazy machine ;-}

 

[rwaterman00]

its kool you guys are able to make a living building MB. I have gotten offers to buy the bikes I have built but can never bring myself to part with them. besides it takes me too long and I would have to charge too much for the bikes. the bike I just finished it took about a week of messing with it to just get the carb adjusted proper.

 

[crassius]

yeah, but dinner is chewing on an old shirt I spilled soup on