96 CR 125 compression?

[440racer]

Help Please - 96 CR 125 compression?

I just picked up a 96 cr 125 and it won't start. Spark's good.

Compression feels low. I'm going to pick up a compression gauge today and check it but I can't find a specification for this motor.

Does anybody know the minimum reading I should look for?

 

[CRazy250]

just take the 2 hours of time and replace piston and rings if you can,as for compression i dont know. try soaking the carb

 

[440racer]

I was halfway planning to replace the piston & rings. Probably won't cost much more than buying a compression tester anyway. Just thought it would be good to know compression.

About soaking the carb. What's the best solution for soaking a carb?

 

[440racer]

I didn't think it was getting any gas, but I was spraying starting fluid in it and still nothing.

Last night I took a working carb off my 93 cr125 and still wouldn't start so I started to take the cylinder off to replace the piston & rings but thought I would check the power valves just to make sure they weren't stuck open and whatya know, they were both stuck open (really stuck - full of carbon). So they're soaking now and I'll try to put it back together before pulling the top end and see if she'll start'

Thanks for ya'lls help!

 

[Matt90GT]

FYI if you are below 130 psi on compression, you need a rebuild or have like a head gasket blown. You should be between 170-210 as a general rule.

 

[440racer]

Thanks Matt90GT! It is good to know a guideline for compression. I hope after cleaning and re-installing the exhaust valves that I'll have good compression. But now I know what to look for as a minimum after that.

Thanks again.

 

[ThunderGoat]

130? yeah on a four stoke.... lol i have a freind who has a husky 360 that was running(although not good) on 25 psi. im not sure what normal compression is on two stroke but im sure they will run on a lot lower than 130

 

[440racer]

Thanks guys for the info. I just put a brand new piston in a newly nikasil plated cylinder on another bike. After I get the exhaust valves unstuck and reinstalled I'm going to check compression on both bikes and post the results. I hope the bike with the newly cleaned exhaust valves will start then.