compression loss, please help

[mcohen08]

my bike (2 stroke) has lost all its compression. i think its the top end rings, my dad thinks its the reed valve. i am so sure, but my dad insists thats not it. please help - thanks

 

[grass-digger]

i think its the top end my bike still have compresion with the reed cage token out

 

[Glitch]

I dont think that there is anyway it can be the reeds. I do know that it is either the rings, head gasket, or theres no spark plug in the head.

 

[Danny8785]

Its the top end. The reeds cant cause compresion loss, but they can cause hard starting and poor running.

 

[grass-digger]

to give us a better idea of whats wrong how about you ecplain how it happend

 

[mcohen08]

well, considering what was said about hard starting and poor running caused by the reed valve, then that could very well be the problem. there is still very little compression. maybe i should hit two birds with one stone when i tear down my bike.

What happened - My bike became impossible to kick start (no compression), so i had to roll start it every time. then, later on, in my high rpm's it would start to put-put-put. i changed the spark plugs so many times, what a waste.

 

[yzeater]

Where in VA are you?

 

[Rockey5000]

Originally posted by mcohen08
maybe i should hit two birds with one stone when i tear down my bike.

Exactly

 

[Hogwylde]

Originally posted by mcohen08
there is still very little compression. maybe i should hit two birds with one stone when i tear down my bike.

Welcome to the world of two strokes!! These engines dont run forever like 4 strokes do. You have to do maintenance on them....which means top end rebuilds frequently!!! You have classic ring wear with loss of compression. You shouldn't have "very little" compression. You should have WHOLE gobs of it!!! That's why you have to push start it.....gets the piston moving fast enough to create some pressure in the cylinder. (remember...and engine only needs 3 things to run.....fuel, spark at the right time, and compression).
Since you're gonna be doing a top end job, won't hurt to inspect your reeds.

Oh.....you need to hit more than "two birds with one stone". You need to check rod bearing and main bearing wear while you have things torn apart. If you have power valves, these need cleaning and lubing also.

 

[mcohen08]

Yes, I know 4 strokes have a longer more reliable life than 2 strokes, thanks for clarifying that. And no, I dont have "whole gobs" of it, my kick starter pushes over like twig. My best friend's bike takes some effort to push down the kick starter. And I do do maintenance on it. Tearing down your top end often when you aren't racing it or riding it hard frequently is not maintenance. Thanks for the the other tips though. Although, don't assume so much when you give adivce next time.

 

[mcohen08]

I'm in Lexington.

 

[Hogwylde]

Originally posted by mcohen08
Tearing down your top end often when you aren't racing it or riding it hard frequently is not maintenance.

O, I beg to differ grasshopper. Recommended replacement intervals for rings is every 5 hours and pistons is every 10 hours. (I believe that's Eric's site recomendation) This is total accumulated time, not "racing or hard riding" time. Now these aren't written in stone and some bikes will last longer, and some shorter. Also, since your bike is 16 years old.....(hey..it's older than YOU!)....there is a good chance the cylinder is worn out...which would make a new set of rings and piston last no time at all.

 

[mcohen08]

<learn how to post if you want to stay a member>

 

[Rockey5000]

Originally posted by mcohen08
Oh you beg to differ? How about you kiss my ass.

And how about you get the **** out of here until you mature a little bit more. Grow up.

 

[mcohen08]

i bought the bike with a new cylinder, wiseco piston, and a new rebuild. i hadn't rebuilt my bike in months and it ran fine. thanks again

 

[clutchcover]

You could have snapped a ring, or could have gotton crap in there causing it to wear out faster. Hogwylde did tell you exactly what you needed to know. He was right in everything he said. Smaller bikes that must rev higher to keep going the same speed a some of their older brothers need topend service more often. The recomendation for an 80 is 5 hours, 125-10, 250-20, 500-40. I think this is what Eric Gorr posted on his site anyway. Someone correct me if I'm wrong. You said it yourself..."I hadn't rebuilt my bike in months and it RAN fine" It's because you hadn't rebuilt it in months that it is now worn out.

 

[Durt Cycler]

Sounds like a ring seal failure to me. Overly worn piston rings will do this and cause blowby. I tear it down and do a topend and measure everything to see if they are still within spec.

 

[r_rider28]

Is somebody sensative or what? I'm afraid to recommend anything for I might get cursed at. It's a 2-stroke with no compression. The problem can only be in one place, inside the cylinder. Tear it down and see what you find, I'm sure you will find something in there is not meeting the OEM's specifications.