97 rm125 low compression on new top end

RM317
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4/1/2018
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CA
RM317
I helped a friend rebuild his 1997 rm125 it took like 10 kicks to start up the first time. He took it out for a ride today and ran fine for 2minutes then started sputtering. Now the bike wont start and ge said it has low compression. Any causes and how do I fix this? Thank you!
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kb228
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1/31/2018
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Mansfield, OH US
kb228 4/2/2018 1:12am
4/2/2018 1:12am
Try again on the rebuild. This time double check piston to cylinder cleaeance and ring gap.
Hondas4Life3
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Louisburg, KS US
Hondas4Life3 4/2/2018 7:17am
4/2/2018 7:17am
Piston ring stuck? Installing without lube or with debris in the engine will cause that.
Paw Paw 271
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Benton, LA US
Paw Paw 271 4/2/2018 2:19pm
4/2/2018 2:19pm
Also if the ring end gap was to tight will cause the ring to stick.
An air leak will cause a lean condition that will cause it to over heat and stick the ring. A bad crank seal caused by a bad crank main bearing will do the same.
A rod bearing can cause the same thing as the excess heat will travel to the piston.

Paw Paw

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