Super Jet Compression question?

[brylon644]

My 2001 super jet starting running bad a while back. While riding would not reach full rpm, but fine up to half throttle. Cleaned the carbs today and checked connections. Still does it! Checked the compression 150 psi in the front cylinder and 130psi in the back. So I realize the motor is bad but I want to make sure that the low compression is the cause before I tear it all down. So my question... would the low compression in the back cylinder cause it to run bad? Or do I need to investigate more?

 

[All stock 701]

Yes, the low compression is definitely a problem and could very well be your problem. My guess would be that a reed broke on the rear cylinder and went through the motor causing damage contributing to low compression. I would pull the motor out and inspect everything carefully while disassembling it to find anything that could contribute to poor running. Generally compression should be within 10% between cylinders.

Zack

 

[Vumad]

Leak test before and after you take it apart. You don't have to... but... You want to find the cause so you should test before. You want to make sure its right so you should test after,