gearing question, help please

#1
I'm trying to narrow down my choices on gearing a bike. I can't afford to buy 10 sprockets to test. Hopefully only one or two..
Lets say a good running 6 horse engine that will only be turned to, say 5K.
I'm going to run a 30 series clutch set up on my jackshaft, then I need my output sprocket to go back to my 60T rear.
I'd be happy with a compromise ratio for street and hills.
I don't really need a wheelie machine but it does need to have some snot.

Specs:
6HP
5K RPM
Comet 30
____?____ tooth output sprocket
60T rear sprocket
14" tires
 

delray

Well-Known Member
#3
randy when you say 30 series clutch? do you mean torque converter and the sprockets you want to use,are they 35 or 40/41 teeth.
 
#4
Randy, How many teeth on the Comet 30?
None:shrug: That's my clutch. A belt clutch.

randy when you say 30 series clutch? do you mean torque converter and the sprockets you want to use,are they 35 or 40/41 teeth.
No, not a TAV unit. I'm using a 30 series driven and driver from a TAV but I'm mounting the driven directly to my JS. I want something different and when you use a TAV on a Bonanza they look weird because you have to stand them up. My sprocket will be a #35 chain.
Bonanza had a few 'TC' bikes. Basically thats what I'm doing.
I'm mounting a driven to the outside of the JS:thumbsup:
 

kbs8ball

Active Member
#5
Do you have a tall jackshaft mount frame? im thinking 15 or 16 teeth with that 60 tooth on the rear. I eventually want to build the bike in that bottom pic.
 

delray

Well-Known Member
#7
ok randy:thumbsup:,if thats a big block 6hp you are running or even a small block built up to a 6hp? it won't take much off set gearing to push that bike down the road and do everything you want it to do.......:scooter:
 

MB165

Active Member
#8
Id go with a 10t. 9t if you can get it. Either of those setups will give good power at low speeds and if there room and enough power your lookin like 35mph at 5K rpm. That should be a good setup.

I went to this website and plugged in your specs
MOTOR - A Rear Axle Calculator

tire dia 14"
I used 6 as the rear axle ratio (assuming 10t-60t sprockets)
the 30 series is anywhere from 20:1-1:1 (Assume 6" driven?)
and 5000 rpm

at 5000rpm, fulll clutch shift (1:1), your appx. 35mph

whatta ya think?
 
#10
Hey Randy
What I used on the bike I had at Windber was a big block 6hp Tecumseh with a 30 series with 10 tooth on jackshaft plus I had a spare 12 tooth gear on the jackshaft that could be put in place of the 10 tooth to change the ratio if needed be and 60 tooth on rear sprocket and it performed very good on every terrain. I ran the 10 tooth and 60 tooth the hole time I was there with no problems. I never tried the 12 tooth.
 
#11
Thanks guy's, I'll stick a 10 on it..

Kenny, it has the normal JS mounts. My clutches are in the mail so I'll have them in a few days and I'll know where it all falls.
I'm guessing they did that for ground clearance?
 

george3

Active Member
#14
If you are going to use 6" rims 60 tooth sprocket 14" tires I would go with 12 to the 60 tooth sprocket. just use the calculator. 12 to 60 with 14" tires.
 
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