RMZ450 seized

[Dirtjunkie85]

So over the weekend a group of us were out riding the bikes! and my budies RMZ 450 seized up.
We were riding on the road when the tire locked up and stop, you cant kick or push start it.There was oil in it, we are hopping that is going to be a easy fix.
What does it sound like to you guys?

 

[Papakeith]

It is an easy fix.
Unscrew the spark plug
roll away old RMZ
roll in another RMZ
screw in spark plug
go ride!
:ride: :)

 

[Papakeith]

If it locked up there could be a myriad of issues involved.
It could be seized piston
It could be valves breaking apart and locking up the works
etc, etc, etc.

Unless you get real lucky and there is a rock between the chain and the sprocket keeping the wheel from turning; the only way you will know for sure is to tear it down, inspect and build up a parts list.

 

[rmc_olderthandirt]

What does it sound like to you guys?

Yep, sounds like it seized.

Unfortunately, there is no way to establish the extent of the damage until you take it apart.

I've burned a hole in a piston and had no other damage so that it was only a new piston and gaskets and I was good to go.

I doubt that your buddy will be so lucky. If it locked the rear wheel up it means that it seized hard enough to really jam things. This usually scores the cylinder wall which requires boring, sleeving, plating or some combination of those.

On a two stroke you are frequently lucky to have the damage limited to the cylinder. On a four stroke it is possible for the head/valves to be damaged in the process. If pieces of the piston have broken off and are down in the crank area you may have damage down there as well.

If the piston is still stuck (ie you can't kick it over) then you will have an additional problem that it will be very difficult to get the engine apart. I recommend that before you start tearing into it you remove the spark plug and pour some light oil into the cylinder and let it soak for a bit. Put the bike into a high gear and rock it back and forth to try to break the piston free. Be careful, if you get too aggressive you risk damaging the gear case and/or rod. But your alternative will be to remove the engine entirely and chisel the piston out.

Have you checked to oil? If the reason that the piston seized was because it ran out of oil then there is a very high probability that a lot of other parts are damaged as well.


Rod

 

[Rich Rohrich]

As Rod pointed out start with the basics. Pull the clutch cover and look for something obvious keeping the crank or clutch from turning. If you don't find anything pull the presure plate and clutch plates to verify if the transmission and engine will turn independently of one another. If the trans will rotate but the crank will not, start by pulling the cam cover and check for seized cam bearings and problems with the cam chain. These engines have a manual cam chain adjuster that is often neglected. More than a few engines have been hurt as a result of that type of neglect.

 

[Dirtjunkie85]

Thanks guys for the help and advice. We took the spark pulg out and it looks like the piston was hitting the plug. So they started to pull the top end to do some replaceing.
I guess he going to put a Wiseco Piston in it. My budie was so pissed off because he just bought the bike last wednesday(4/27) and this happened.

 

[Papakeith]

Not good news when things start hitting the piston.
was the plug the proper plug for the bike?

 

[Dirtjunkie85]

Not good news when things start hitting the piston.
was the plug the proper plug for the bike?

You know im not sure. I have not been helping them tear it apart.

 

[Dirtjunkie85]

Its worst then we thought. It ended up being a Valve, they should have been adjusted but he did not know they needed to be, so he sucked a valve. He needs to rebuild his head or buy a new one.