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Any oil seal experts?
MikeRJ - 31/1/12 at 10:00 PM

My dad is restoring an old (1960's) Gilera motorbike and has had no luck trying to find fork seals for it. I have spent a long time searching to no avail, mainly because of the extremely spindly fork tubes which are only 22mm diameter - even modern push bikes have bigger forks than this!

One thought I had was to use a conventional double lipped oil seal which are readily available for 22mm shafts, and I could machine a carrier to fit a ~30mm outer diameter seal into the fork housing (actual housing diameter is 33.2mm). However I presume there are some design differences between seals that are designed to seal a rotating shaft, and ones that are designed to seal a sliding one. Is this likely to last a reasonable amount of time? I doubt the bike will be doing much mileage.

steve m - 31/1/12 at 10:33 PM

22mm forks ? f**K me, thats thin !

My cheapo halrauds push pike has 26mm

MikeRJ - 31/1/12 at 11:03 PM

They are ridiculously small by modern standards, though the tubes have a much thicker wall than any of my bikes. This is what it should look like when it's not in hundreds of bits like my dads bike.




[Edited on 1/2/12 by MikeRJ]

daviep - 1/2/12 at 04:05 PM

What is the the size of the groove?

A rod seal from a hydraulic cylinder would do the job fine I would think. Have a look HERE or try a local hydraulic supplier.

Regards
Davie

tegwin - 1/2/12 at 04:55 PM

Some damper struts (IE Gaz, spax etc) have 22mm shafts....

MikeRJ - 1/2/12 at 11:22 PM

quote:
Originally posted by daviep
What is the the size of the groove?

A rod seal from a hydraulic cylinder would do the job fine I would think. Have a look HERE or try a local hydraulic supplier.

Regards
Davie


There is no groove as such. It looks like the original seal was simply clamped in a recess in the end of the fork slider by a threaded collar. Through the magic of "Paint" I have tried to show the rough idea here. The red is the seal, the blue is a steel washer.



I'm liking the hydraulic ram seal idea though, thanks for that idea. Typically I was looking on the SKF web site a couple of days back and never though to look at these.

quote:
Originally posted by tegwin
Some damper struts (IE Gaz, spax etc) have 22mm shafts....


Interesting...can you get spares for these? If so where would I start asking?

[Edited on 1/2/12 by MikeRJ]