Gear ratio question

[r_chez_08]

Ok I am unexpierienced with mini bikes gearing.
I saw the thread in the karting question section, and so I took the questions from it.
I would like to know a suitable pulley diameter for the torque converter.

We need to know

1. Tyre diameter, as in, the actual diameter, not just "oh about 10 inches".
2. What engine you have.
3. What RPMs your engine is capable of.
4. What kind of clutch/drivertrain you have.
5. If you have a jack shaft.
6. Current number of teeth on clutch or torque converter (if applicable).
7. Current number of teeth on axle or jack shaft sprocket (if applicable).
8. Weight of kart (bike) including rider.
9. What terrian the kart (bike) is used on.
10.What kind of top speed you are expecting.

1. 11"
2. Honda GX160
3. 3600rpm at the moment, but may remove the gov for 4500 later.
4. Comet Torque a verter tav30 and belt drive
5. I have a jackshaft and a 70mm PCD pulley to a 145mm PCD pulley on the wheel
6. This is what I want to figure out.
7. At the moment I have:
engine: I want to work out
J/S in: 145mm pulley
J/S out: 70mm pulley
Rear wheel: 145mm pulley
8. I weigh 140LB, the bike probably just over 100LB if that.
9. Farm tracks and the odd relitavely flat field. Dirt hills.
10. I want atleast 20mph, but I would prefer to pop wheelies than go 40 with no torque.

I have a 35mm pulley that I could put on the torque converter jackshaft, but I think it would be too slow and the belt will slip.
It also only gives me 14mph!

I can buy this to put on the jackshaft, which would give me a 5.2:1 ratio and about 23mph. Would this be OK? I would make a keyway with a small file.

BTW to find out the effective pulley diameter of an A section pulley take the diameter and subtract 5.5mm

Thanks
Rob

 

[r_chez_08]

Anybody?

 

[B.M.800]

The baja heat/warriors are geared about how you want, in another thread blazkowiz(dunno how to spell his name) said putting a tc the bike would weelie by it self. I know with a small bump the bike can lift up pretty easily...

The second day I had my heat i went in a dip and came up the other side the front stayed up.

 

[r_chez_08]

ok sweet. The only problem is the fact the bike is belt drive, and it will slip a bit. Should still be good tho.
Also the weight is near the front, but I can always lean back.
I have sent the guy a message to see if that pulley is for A section belts like I have.

 

[B.M.800]

I dont know much about belt drive yet, but I would think if it is tight enough there wouldnt be much slippage...

 

[r_chez_08]

Ok, thanks. I have tightened the belt from the jackshaft to the rear wheel and I cannot make it slip, so it should be ok. I think the reason it slipped before is because I had a belt tensioner clutch and smaller pulleys.