400ex gaulded piston HELP!!!

[jdubb]

Can anyone email me some pages from the service manual on removing the piston? How do you keep it in time when removing just the head?

[exrider23]

you cant keep it in time, you have to re-time it when you put it all back together. So dont worry about the timing while your takiong it apart. As for the service pages, i cant help ya there.sorry

[katch26]

Originally posted by jdubb
Can anyone email me some pages from the service manual on removing the piston? How do you keep it in time when removing just the head?

did you already remove the head?
if so the only thing you need to do is remove the 2 circlips on either side of the wrist pin, that will slide out and the piston will pull off

[lpmaster]

timing is not difficult at all on a 400ex...do not worry about trying to keep it in time.

just remove one fo the circlips on either side fo the psiton pin and pussh the pin out fromt he othersideand pull the piston off and replace.

[jdubb]

I haven't took the head off yet bc I don't know how to time it. If the chain falls off the bottom sprocket how will I fix it with out takin off the side crankcase cover?

[400eXr1d3rZ]

***DELETED***

[jdubb]

I ulled the head and the jug today...Piston looks good. Crank is blue around the rod bearing. Could I have spun it?

I was coming out of a turn pretty hard when it lost all power, started knocking at idle, and wuldn't rev up.

[Got Boost]

did it start and idle? how loud was the knock? what does the oil look like? what do the cyul. rings look like? I don't think you would loose all of your power if you spun a bearing, you would hear alot of noise, and have a catastophic failure.

[jdubb]

Originally posted by Got Boost
did it start and idle? how loud was the knock? what does the oil look like? what do the cyul. rings look like? I don't think you would loose all of your power if you spun a bearing, you would hear alot of noise, and have a catastophic failure.


Yes it idled, loud knock, rings look good, cylinder wall smooth, and wouldn't rev over half throttle.

[lpmaster]

have you looked at your carb, i had somethign like this happen when my slide came un-screwed from the arm that lifts it and the knocking was just the enigne kind of lugging because of the lack of fuel/air, wasnt an insanely loud knock and very inconsistent.

also to the timing question if that chain falls off the sprocket you can put it back on yourself just by pulling the chain up holding both sides of the chai. then hold the chain and spin the crank to make sure the chain spins with it. after that put the flywheel back tot he timing (tdc) mark and re-install the cam with 2 lines parallel to the top of the head and the 1 line perpendicular to the top of the head

[jdubb]

I'm pretty sure it's not the carb. I've already got it apart and the crank is blue at the rod bearing.

[GPracer2500]

Originally posted by jdubb
I'm pretty sure it's not the carb. I've already got it apart and the crank is blue at the rod bearing.

Some discoloration of the rod is normal. Usually somewhere around the halfway point on the rod it changes color. It's like that because they heat it when the crank is being assembled at the factory.

[jdubb]

it's at the bottom and the crank is blue.