87 rm125ahhh i just did the rebuild and ahhh!!!!!!

:bang: ok,, would riding in the cold screw up your bike? i have an 87 rm 125 and just spent 1300$ on it doing a total top and bottom end rebuild on it,, and i put 5 hours on the new engine going slow,, i haven't even had it full throttle,, so i'm going down the road in 6th with half throttle,, i slow down,, and then i try to pick up speed,, and then its like i'm driving while holding the brakes,, i got about 5 meters and slowed down and it stalled,,, i called the shop and he said i melted my piston? wtf can some one explain how i did this? the bike wasn't even hot when i stopped? :bang:

rm 125

i've been running it extra ritch for the cold,, and i did change the plug,,

it doesn't start,, the piston was all done right,, and i've had five hours of riding on it before this,, it turns over,, but just doesn't sound right, the top end lost compression i think,, but why would this happen?