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Stop running after rebuild

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I got my 2001 rm80 bored out from la sleeve and they gave me a pro x piston and I did the heat cycles and i was riding and the back wheel locked up and didn’t start and have low compression now and have marks in the cylinder. I was told to run 32 to 1

 

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In what conditions did the engine lock up?

Were you 'road riding' or in open terrain (sustained high rpms)

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Never drilled lube holes in piston for bridge i bet.  Can see it rubbed there but id check your bottom end 

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Never drilled lube holes in piston for bridge i bet.  Can see it rubbed there but id check your bottom end 

Do you have to drill the holes even if it is a cast piston? I know that pro x pistons are cast and expand different than the foraged pistons.

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12 minutes ago, Zack Brappp44 said:

Do you have to drill the holes even if it is a cast piston? I know that pro x pistons are cast and expand different than the foraged pistons.

The only time you can get away without is if they relived the bridge.  But still good to do on 85-125 that get rode hard. Not saying its exactly what caused your problem.  You have to let bike warm up good before ripping on it with a steel liner.  

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In what conditions did the engine lock up?

Were you 'road riding' or in open terrain (sustained high rpms)

 

I was on the road in 4th gear blipping the throttle

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The only time you can get away without is if they relived the bridge.  But still good to do on 85-125 that get rode hard. Not saying its exactly what caused your problem.  You have to let bike warm up good before ripping on it with a steel liner.  

This is my first 2 stroke but I made sure to warm the bike up and never to engine brake.

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7 minutes ago, Midcity said:


This is my first 2 stroke but I made sure to warm the bike up and never to engine brake.

Dont worry about engine break thats b.s . Like i said earlier you could have worn out bottom end causing it to run hot at exsaust port which can cause what happened 

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Dont worry about engine break thats b.s . Like i said earlier you could have worn out bottom end causing it to run hot at exsaust port which can cause what happened 

Thanks you so much for the help.
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This is my first 2 stroke but I made sure to warm the bike up and never to engine brake.

Like moto x said it could have been a worn bottom end rod bearing. The same thing happened to my KX125 and it scratched up my cylinder like yours. Check the rod for up and down play.

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The rod have a lot of side to side movements.

There should an a few thousandths that the rod can move back and fourth, that is normal. The bad thing would be if the rod has any up and down play. It would not move too much side to side but I little is ok. Get the rod top dead center and then lightly pull the rod and see if it pulls up any.

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I'm not a 2T expert, but it looks like the power valve is involved. Do they need massaged with bigger bores?

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Hard to tell but something looks funny with crank.  Is one of the thrust washers chewed off ?

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