Jackshaft

Your asking about a straight gear not a clutch driver ?
Clutch drivers we ran our same bully style .
Square drivers or screw in would be different .
 
Your asking about a straight gear not a clutch driver ?
Clutch drivers we ran our same bully style .
Square drivers or screw in would be different .
The 3/4in inside drivers, one goes directly onto the crank and the other on the jackshaft, then clutch is on opposite side of jack shaft. We currently run belts on our setup and i'm over it. Kids break them weekly, put a brand new one on this week and broke with about 5 laps to go. I'm sure it might be something with the pulleys this time but thats two weeks in a row and i'm just done. I know 219 is a tick better than 35 so i'm hoping to find them. Need a 20t and 30t
 
Your belt pulleys could be worn out. If they’re sharp on the edges it’s time to toss them and get new ones. Tension and alignment are also the other key factors.
 
Racinnut, There has to be something drastically wrong with your jackshaft setup. If you are using the normal kart jackshaft 8mm belts and tensioning them correctly, about a 1/2" up/down and not terribly tight, they should last for years (we had one go for 8 years power by a 500cc Jawa). We finally replaced it and now use it as a spare in case we get a rock and it de-tooths the new belt. Check your alignment and get it 100% square with each pulley. About the only thing that ever destroys them is the small rocks from the track getting between the pulley and belt. You may have to put some type of a guard on the outside of the jackshaft to prevent the rocks from getting on the belt. Good luck........
 
Racinnut, There has to be something drastically wrong with your jackshaft setup. If you are using the normal kart jackshaft 8mm belts and tensioning them correctly, about a 1/2" up/down and not terribly tight, they should last for years (we had one go for 8 years power by a 500cc Jawa). We finally replaced it and now use it as a spare in case we get a rock and it de-tooths the new belt. Check your alignment and get it 100% square with each pulley. About the only thing that ever destroys them is the small rocks from the track getting between the pulley and belt. You may have to put some type of a guard on the outside of the jackshaft to prevent the rocks from getting on the belt. Good luck........
Also what engine package/clutch are you running?
We are running world formulas about 15-16hp on our dyno, everyone else claims 19-20 but we keep up and have won races. It has a 3disc SMC clutch on it, run bullys as well but this car came with SMC.

Its not just me, you see multiple belts per week laying on the track. They are only the 20mm belt. Its possible the pulleys are used up, it was used when we got it. I have just been buying cheap belts and replacing every 3rd race as i had one break the 4th.
 
∆∆∆∆∆∆ agreed with both have ran them for years on enduro karts making way more than 25hp for 45 minute races later Chuck.
 
If this is on a Junior Sprint...….get a fresh set of Pulleys and use a 30mm wide Belt.

If you think you are reducing friction by running a 20mm wide belt, you are mistaken.

Those rear tires on 8.0" wheels are going to negate any drivetrain weight/friction savings by running a narrow belt.
 
If this is on a Junior Sprint...….get a fresh set of Pulleys and use a 30mm wide Belt.

If you think you are reducing friction by running a 20mm wide belt, you are mistaken.

Those rear tires on 8.0" wheels are going to negate any drivetrain weight/friction savings by running a narrow belt.
i tend to agree the extent some of these guys are going to lighten pulleys and ti jack shafts and how small of a diameter all that stuff is splitting hairs and the DNF's arent worth it.
 
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