Crankshaft oil seal and key

Hi Norton people I have changed the seal twice now (still leaks) and have just got a new rubberised one from Maney racing.
My question is that the woodruff key runs really close to this seal and the depth of the groove for the seal looks as if it should be deeper .
Has anyone modified the groove or the woodruff key ? I think I could make up a tool to bore the face whilst engine in frame and make the groove deeper or shorten Key .Any thoughts appreciated
This is on a 750 commando with a belt drive .

Mine has always leaked a little due to the fact that the PO seems to have held the crank in a vice at some point.
The metal rimmed ones alway seem to fall out even if I loctitie them in so I use the rubberised ones .... you can get them from any bearing store you don't have to order them online and pay double the price.

I'm trying to think back, but I recall my local bearing dealer found a double lipped seal that worked better but was a little deeper so stuck out a bit.

If there is even the smallest groove worn in crank by old seal then it will affect the new seals ability to seal. The tolerance for both size and surface finish are very important to live an performance of a seal. Go to good bearing suppliers an look for double lip type or a good quality standard type. I would not personally try to machine the seal bore area with crank in place I would strip engine.
Are you sure that the seal has not failed for some other reason like excessive crank case pressure or bearing starting to fail etc. As the seal normally works well as good as any British bike seal (here come a flood of complaints about that last line)

oldman said:

Hi Norton people I have changed the seal twice now (still leaks) and have just got a new rubberised one from Maney racing.
My question is that the woodruff key runs really close to this seal and the depth of the groove for the seal looks as if it should be deeper .
Has anyone modified the groove or the woodruff key ? I think I could make up a tool to bore the face whilst engine in frame and make the groove deeper or shorten Key .Any thoughts appreciated
This is on a 750 commando with a belt drive .

Click to expand...

I observed the same thing, shortened the key about .060". It was closer than I was comfortable with. As another measure, perhaps put the seal against a belt sander (back side metal shell) and lose .020" would probably work well also. :idea:

I sand down the back side w/metal lip just a bit to help the seal find a new "spot" on a scored shaft.
A good machine shop could help restore any scratches or gouges on a shaft but only while engine is apart.
Mike :cry:

The woodruff key is the easiest thing to alter by simply filing a little off if needed an if you are unsure or mess it up it is easily an cheaply replaced. They are not always same profile from one maker to another so it may need dressing the fit of the taper carries most of the force of drive if the end nut is tight an the sprocket an crank tapers fit as they should so you can afford within reason dress it back.

Hi

Are you sure it is the seal leaking?
One of my early race engines leaked & I changed the seal twice at one meeting.
Turned out to be the cases being porous.

Chris

Chris said:

Hi

Are you sure it is the seal leaking?
One of my early race engines leaked & I changed the seal twice at one meeting.
Turned out to be the cases being porous.

Chris

Click to expand...

Or the chaincase fixing bolt at the 5:00 position.