Major Problem

[MadMattMan]

I'm currently trying to sell my '98 RM 125, but I can't. I might end up having to sell it for a third of what it's worth.

For some reason after an hour and a half of riding, it just stops running. I've friend 4 stators, tried 4 different spark plugs too. Could it be the crank case or bearings? I took it to one mechanic that said the bearing is busted and then I got all excited and took it to an inexpensive mechanic to have it fixed but he put a tester on the needle and told me that there isn't any movement on the crank case. I'm at a loss here. The crank doesn't move when starting. Does anyone know? I've taken it to 3 mechanics and they don't know what's wrong with it. Please help!! Thanks..

[Zooki]

What do you mean by "the crank doesnt move when starting"?

Are you saying you cant kick it over?

If so then it sounds like its seized.

After an hour and a half of ruinning what does the spark plug look like?

The plug generally can tell u exactly what is going on.

When it does run are there any weird noises maybe knocking?

how long after it stops do you have to wait to be able to start it again?

What needle did they put a tester on? that doesnt sound right to me.

Which bearing did the mechanic say was busted? There are heaps of bearings on the bike.

You said "I've friend 4 stators" Did you mean you fried 4 staors or maybe tried 4 stators?

What country are you in?

[MadMattMan]

Let me try this again lol:

I have this bike as mentioned above. After frying 4 stators w/ 4 different spark plugs, I took it to a mechanic. He said that the crank bearing needs to be replaced because it is touching the rotor causing a short. So, I thought, "okay, I will take it to an inexpensive mechanic to have the bearing replaced." I took it there and the 2nd mechanic told me "I don't know what the other guy was talking about, but there is no movement on the crank when the bike is not started." There is a quarter inch space between the stator and rotor. I don't see much movement when the bike is not running. Would there be movement on the crank when it is running that I can't see when it isn't running? I don't want to go and replace the bearing if it isn't the problem because it is an expensive fix. I've already replaced the CDI box, and isolated all the wires from the CDI box down. What is causing these stators to fry?

[Zooki]

If the crank shaft is touching them then it will show up as a worn area.

It certainly sounds feasible to me.

The shaft should not have any movement in it whatsoever.

[Zooki]

Oh, one other thing..........there will be at least two bearings for the crank shaft, one on either side and sometimes others in the middle as well.

Its not necessarily the one cloest to the stator thats gone.

It could be one on the opposite side.

[MadMattMan]

So it could be any of the bearings that are causing each stator I replace along with spark plugs to fry?

[Dave2122]

If you had a crank bearing that went bad your bike would have not been able to run without making MAJOR noises. If you have fired 4 stators you have an electrical problem either with your CDI or in the wiriing harness.

Here are some things to check.

Does the motor turn freely by hand?
Does it make any grinding noises when turned by hand?

Now you will need to have a Fluke Meter or similar unit and test your CDI for its output.
Also check the Pickup coils to make sure they are good.

If you can not do this take the bike to a reputable motorcycle mechanic as it is not something that you can do if you have no manual and no knowledge of the procedures. Sounds pretty far fetched to have the main crank bearings so bad the crank is moving. It can happen BUT I highly doubt it is your problem.