Fitting kickstart oil seal (1965 B40F)

[Phil C]

Further to my previous email a few minutes ago, I should explain that the bit of the seal that was sticking out slightly was on the seal's outer circumference, not the part that actually contacts with the shaft.  Phil

[Phil C]

Here's a photo. You might be able to see the slight deformity of the outside edge of the seal at about 2 o'clock. That's what I pushed in using the rounded end of a six- inch rule. Sorry, no photo yet of the seal after that. Any thoughts please?  Phil

[Pete Gill]

Hi Phil
It would seem that either the outer diameter of your seal is too big or you're trying to drive it in skewed.
I have found that some suppliers seals are not as good a quality ( they might be metric equivalents rather than imperial?)
I have in the past shaved down the outer diameter of a seal with a file to persuade it to fit when i was in a similar situation.

[Phil C]

Thanks Pete. I'm trying to keep it straight. Hadn't really considered that the seals might be metric, but after your suggestion I've just measured the O/D of one of them and it appears to be about 1.013" (so thirteen thou over an inch.) That might be the correct size for an interference fit, I don't know, although it's a bit bigger than I expected. But I don't think it corresponds to a metric size. So I'm still a bit puzzled. I got them from Kidderminster Motorcycles, who always seem to be very good (excellent for quick delivery, by the way.) Any suggestions, anyone, for another supplier? Or any thoughts on the size?   Phil

[Phil C]

By the way, there's no metal collar on these seals, they're all rubber/plastic.

[Phil C]

Me again. I think another factor might be slightly raised bits on the circumference of the hole. So with two things in mind (seal O/D, and hole wall), and armed with a small file, and much care, I think I'm on the way to sorting out my little problem. Certainly go on about my little issues, don't I?  Phil

[Pete Gill]

This oil seal size is commonly used on a few bikes in a few different places.
This size is the one that fits on the end of the exhaust cam behind the auto advance on triumph Twins and tridents as well- I've fitted on both.
I just measured one and external diameter i get to be 1.003 - 1.004"
I think yours is too big.
Try one from a different supplier? let Kidderminster know they don't seem to fit - think they'd be wanting to know that there are problems with their sizes.
Pete

[Phil C]

I think a raised area on the hole wall was significant. Having done a bit of careful filing on it, I've just fitted a well- greased new (Kidderminster-supplied, the one I measured) seal (casing on bench) by pushing hard with thumbs. I'll see how it goes on the shaft this afternoon. Interesting, Pete, that your seal has a smaller O/D.   Phil