My bike won't start and i can push it when its in gear!!!!!?

Question

my yz 125 won't start i just put a new piston in it today but did'nt get the barrel replated and now i can push the bike when its in gear whats going on???

Answer 1

Wrong size piston and rings maybe. If you know the piston is correct, try some oil in through the plug hole and leave overnight as the rings may be sticking in the grooves. Did you position the rings so the gaps weren't all in line? Lose a lot of compression with in line gaps.

Answer 2

Are you sure it was the correct piston for that model?  Did you have to use a ring compressor when fitting the piston? (you did remember to fit the new rings in the new piston - and to stagger the gaps?)

Answer 3

Iv'e no idea, check the battery and sparks

Answer 4

Sounds like no compression whatsoever. Probably time for a rebore and new piston and rings.

Why the new piston anyway? What happened to the old one?

Answer 5

first thing i would say your cluch is gone

and i think you starter is gone but i need to know if that dose it turn over or not.

Answer 6

Why did you replace it?.Do the pistons match(number/letter on top of piston)?.Is the cylinder scratched?.Pour a wee bit of oil down plug hole and see if there is any difference.

EDIT:You will probably need a rebore and replate,and another size piston.

Answer 7

Perhaps you installed the piston backwards and one of the rings snagged a port and broke.

Did you know that 2 stroke pistons have an arrow on the dome and it should point forward.

If you didn't know that, then that's probably the problem.

Answer 8

take of the piston and put it back in the jug  then wiggle it if it moves more than a touch than it is the wrong size piston or u need new rings.if thats not it take off the head and look at the valves maybe they are not holding the compression.

Answer 9

have you put the spark plug back ???

Answer 10

If you just put a new piston in,its more than likely the head

casket isn't sealed or on correctly,thus no compression,

so you can push it in gear? try it in 1st gear you shouldn't be able to push it. it cant be ya clutch coz yer getting it into gear.

I cant see what being able to push it in gear and it not starting

have in common,a bit more info please dude?

Answer 11

Get a compression test...If there's low compression could indicate piston ring problem

Answer 12

the crankshaft is screwed

Answer 13

HELLO

SOUNDS LIKE YOU NEED A REBORE  OR AT LEAST BARREL RELINED

YOU HAVE SHAXXED IT