Predator Torque Ate My Q-Matic Pulley

[jowens]

Yesterday I had to replace the 5" rear pully because torque from my 99cc Predator had sheared the 3/16" Key and innner hole of the pulley. After getting everything torn apart I was a little taken back at how the motor had done what it did. Think Im gonna have to look for pulleys that are made of something other than Zamak #3 material, preferably steel. Im sure its only a matter of time before it happens again. I have 100 hours on my Predator and if I conservatively consider it I have about 2000 miles on everything with a 9.6 to 1 final gear ratio. But its back to running today so I am happy.

 

[azbill]

the new steel pulleys will solve that dilemma
I believe the way different metals expand with heat is what was causing the issue

I was having probs keeping the setscrew tight, and once it allows the pulley to move a little, the problem just magnifies until the point you are at

I have 300+ miles on my steel pulley and it hasn't moved 1 iota

 

[DTFuqua]

What new steel pullys?

 

[scotto-]

What new steel pullys?

The Q-matics now ship with a balanced steel pulley instead of the Congress pot-metal pulley.

 

[MotorBicycleRacing]

The Q-matics now ship with a balanced steel pulley instead of the Congress pot-metal pulley.

Here is a`pic of the steel pulley on the right.

 

[DTFuqua]

Thank you guys. I'm about to buy a pulley from Granger for my homemade setup and was wondering if there was something I should investigate before buying what I expect to get Friday. I have more than once found myself in the position of "WOW I WISH I HAD KNOWN THAT YESTERDAY ".