oil seals

[Iain Cameron]

Hi Yamaha gurus Ive heard that one can change the ignition side oil seal with out splitting the cases on the yz d 250/400 , Is this possible and how ? thanks in avance Iainyz

[crossedup2]

Hi Iain
Firstly, why are you changing the seal. If it's leaking then the seal is the secondary problem, the main bearing could well be the problem. (or in some cases the main bearing case steel insert.)

To answer your question, yes you can and with a little difficulty. You need to drive a sharpish small flat bladed screw driver in about 1 to 1.5mm from the outter edge of the seal. Then basicly leaver the old seal out. Take your time and its possible. The seal may actually move in a bit before the blade penetrates but don't be concerned about that. Just make sure that you don't go in to hard and damage the bearing.

As a little hint when putting the new seal back in, put a little grease on the inner lip of the seal and the crank to not burn the seal when you start it. And to help the seal over every thing.

Peter B

[Iain Cameron]

Thanks Peter the reason for the change in seals ,after about 10 min running the motor would start to rev higher and higher after checking for air leaks at the carb manifold area (nothing ) checked behind stator bloody iol seal was in back to front (spring on the inside) . How come when we pay others to do work to save time it allways bites us back . yes I use grease on all seals thanks for your info saves a split job regards Iain

[David Lahey]

I usually punch a hole through the steel part of the seal with a sharpened punch and screw in a self-tapper then pull on the self-tapper. Works great