I have recently bought a 2001 yz 125 and its a bit rattly, i stripped the head down, had a look at the piston and rin which all looks ok, whilst striped i cheaked the con rod for play and it was ok, i put a new ring in it as it was stripped and put back together, its still the same and sounds like its got piston slap or something. Anyone have any advise on what it could be?? small end bearing?
ya
id say either a worn wrist pin or small wrist pin bearing. why didnt you check all that while you had it apart last time.
yz 125 rattling
i guess because the piston looked fairly new i thought it couldnt of been the bearing or pin, but i suppose the guy i got it off might of just put new piston and ring and not bothered with the bearing, would a worn pin bearing cause it to rattle? or piston slap ?
it depends
i got thinking about it and it probly would rattle a little bit but i would go around and check all your motor mounts. and a pin bearing cant cause piston slap because piston slap is caused by having to small of a piston for the cylinder which results in the piston hammering on the cylinder during the change of motion in the piston.
yz 125 rattling
well its coming from the top end, its nothing loose or rattling on the bike. Do you think i should just change the piston/ring and bearing and see if it makes a difference?
nah
thats pretty pricy but it might be all you can do but if it is to much piston clearence you can measure the piston and cylinder and it its out get a new piston. do whatever you figure.
check
check the power valve. my bike had the bushings in the power valve go out and the power valve hit the piston and took it out.
yz 125 rattling
Just a bit of an update, i started it up today and it sounds fine on tick ove its just when you rev it?? Does that mean anything?
hmmm
its probly not anything intirnaly wrong than. its just something loose. check your power valve, exhaust springs, pipe fittings, front motor mounts, wiring and anything else you see that could be causing a vibration.
hmmm
its probly not anything intirnaly wrong than. its just something loose. check your power valve, exhaust springs, pipe fittings, front motor mounts, wiring and anything else you see that could be causing a vibration.
yz 125 rattling
I have cheaked all mounts pipes etc to be sure and it defo coming from the engine. I not sure what it is i guess it needs to go to the shop ??
Things like that if you dont
Things like that if you dont know much your better off not messing with it yourself send it to a expert and he will tell you whats wrong with it in a couple of mins try find a person who races motocross that fixes bikes dont send it to a road bike dealer everybody i know that sends there dirtbikes to roadbike dealers end up getting riped off and things are not put back on right.
yz 125 rattling
Took your advise and a bloke from racing had a look, he re homed ( i think thats what it was called) the head as there was a small score and polshed it out and cleaned it all. Came home put it all back together with the new piston ring bearing etc and woo hoo 1st time sounds sweet as. Cheers for all your help :) thumbs up