Rebuilt top end-had good compression, now I don't????
#1
Rebuilt top end-had good compression, now I don't????
1998 Polaris Xpress 300, 2 stroke
Rebuilt top end, piston, rings, and gaskets. Motor was rebored and honed correctly. Put added oil with gas to help break in (done right). Checked top end compression after that and compression was strong. Still no fire. Great spark. Rebuilt carb, cause was getting gas in crankcase. Then couldn't work on it for a month. Got back to workin on it and changed out the clutch side oil seal cause it was leaking out of the crank there I noticed after doing the rebuild. Figured it was ready to go after all that. Went to start it yesterday, it turned but no attempt to fire at all. Rechecked the compression, and it was way to low???????
Any suggestions????????? Thinking I'm gonna have to retear into the motor, only this time the top and bottom.
Thank You
Kelly
Rebuilt top end, piston, rings, and gaskets. Motor was rebored and honed correctly. Put added oil with gas to help break in (done right). Checked top end compression after that and compression was strong. Still no fire. Great spark. Rebuilt carb, cause was getting gas in crankcase. Then couldn't work on it for a month. Got back to workin on it and changed out the clutch side oil seal cause it was leaking out of the crank there I noticed after doing the rebuild. Figured it was ready to go after all that. Went to start it yesterday, it turned but no attempt to fire at all. Rechecked the compression, and it was way to low???????
Any suggestions????????? Thinking I'm gonna have to retear into the motor, only this time the top and bottom.
Thank You
Kelly
#2
has it run at all since rebuild?? sounds like maybe the rings didnt seat correctly. you could try a leak down test as that will tell you alot more then then only a compression check. ive never done a leak down on a 2 stroke, but you would have to make sure the piston has covered all the ports in the sleave...
#5
One thing you must realize about a 2-stroke is seals go out for a reason, for instance it is most likely caused from bad crankshaft bearings. Allowing the crank to 'wobble' inside the cases.
A new seal might work temp. but if the root cause is not fixed it will break down again.
It would be best to do a 'complete' bottom end rebuild, including all bearing/seals.
A new seal might work temp. but if the root cause is not fixed it will break down again.
It would be best to do a 'complete' bottom end rebuild, including all bearing/seals.
#6
Question-
Before I went to change out the seal, I tried to wiggle the clutch to see if there was any play in the crank shaft. It wasn't rock solid tight, but it had an very very minute wiggle. Is that normal, should it be rock solid tight- absolutely NO play, or is that indication of something?
Next Question-
Do you think I did further damage now that I don't have compression again? All I did was try to start it, it never did fire up.
Thank YOU!
Kelly
Before I went to change out the seal, I tried to wiggle the clutch to see if there was any play in the crank shaft. It wasn't rock solid tight, but it had an very very minute wiggle. Is that normal, should it be rock solid tight- absolutely NO play, or is that indication of something?
Next Question-
Do you think I did further damage now that I don't have compression again? All I did was try to start it, it never did fire up.
Thank YOU!
Kelly
#7
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#8
Question-
Before I went to change out the seal, I tried to wiggle the clutch to see if there was any play in the crank shaft. It wasn't rock solid tight, but it had an very very minute wiggle. Is that normal, should it be rock solid tight- absolutely NO play, or is that indication of something?
Next Question-
Do you think I did further damage now that I don't have compression again? All I did was try to start it, it never did fire up.
Thank YOU!
Kelly
Before I went to change out the seal, I tried to wiggle the clutch to see if there was any play in the crank shaft. It wasn't rock solid tight, but it had an very very minute wiggle. Is that normal, should it be rock solid tight- absolutely NO play, or is that indication of something?
Next Question-
Do you think I did further damage now that I don't have compression again? All I did was try to start it, it never did fire up.
Thank YOU!
Kelly
#9
Thanks guys-
Why is it you think I lost compression on the top end though? Someone did mention rings might not have set right. It was real strong right after the rebuild. Will I also lose alot/some/none top end compression with a sudden change in low end compression?
Thanks
Kelly
I will deffinately keep you all posted til the end.
Why is it you think I lost compression on the top end though? Someone did mention rings might not have set right. It was real strong right after the rebuild. Will I also lose alot/some/none top end compression with a sudden change in low end compression?
Thanks
Kelly
I will deffinately keep you all posted til the end.
#10
Thanks guys-
Why is it you think I lost compression on the top end though? Someone did mention rings might not have set right. It was real strong right after the rebuild. Will I also lose alot/some/none top end compression with a sudden change in low end compression?
Thanks
Kelly
I will deffinately keep you all posted til the end.
Why is it you think I lost compression on the top end though? Someone did mention rings might not have set right. It was real strong right after the rebuild. Will I also lose alot/some/none top end compression with a sudden change in low end compression?
Thanks
Kelly
I will deffinately keep you all posted til the end.