I’m about to have a go at replacing the weeping seals on the forks of my ‘01 748R. I’ve researched the process as much as I can, and it looks to be something that I should be able to achieve without too much drama. But I’m having trouble finding any info on how much oil each leg should hold, And am I right in thinking the level should be 100mm measured with the spring in the leg? Lastly, any recommendations on which breed of oil to use? any knowledgeable information would be gratefully received
When I did mine (non R) there were 2 measurements in the workshop manual; one was the volume (450ml iirc but please check for yourself as I may have forgotten) and the second the air gap at the top, in mm, with spring in and before the fork cap was reinserted. As for oil, I used Motul 7.5 but it’s a subjective choice and is dependent upon your weight, the rating of the spring that’s in there and how you want the forks to ‘feel’ as the viscosity of the oil affects the damping rate.
The 748r workshop manual says to refer to an Öhlins dealer for fork overhaul. The Red Baron’s book says the Öhlins Manuals have specifcation sheets for each model. The spec sheet will also say with spring in or out. So, if I were you I would search Ohlins site. If you get it stick a link up please.
If they are FG 320 forks thus link should help. It’s all a bit confusing TBH. https://www.ohlins.com/document/18592/
Ive enjoyed this but unfortunately have drawn a blank. I checked the forks on my 2001 (02 model) 748R They are stamped FG 8500 200 06 08. This is on the inside of the base of the forks, visible with a good light from the opposite side of the wheel. The link below confirms these are the babies, but, discontinued. https://www.ohlins.com/product-item/61496/ So, I would phone an Ohlins dealer (who hold all the information on their systems) for the spec sheet. If you get one, stick it up here please.
Thanks Paul, I have the workshop manual for the R but it’s for a 2000 bike and relates to Showa forks not ohlins, all the YouTube vids seem to be of the 1098 fork, so am struggling a bit at the mo to get the right info, but thanks anyway, oil viscosity will be one to ponder
Have tried that, sorted one leg but not the other, deep joy lol, but it’s definitely a handy bit of kit for little money
That’s brill, thankyou. I haven’t got the forks off yet, waiting on seals landing and a tool to slacken the tops off before I drop them out, If I get anywhere with it I’ll definitely let you all know
I've searched around my files this afternoon and can confirm that the Ohlins article number for the forks on the 748R is 'FG_8500'. I found a hardcopy front fork specification card for the 748R, it states the oil level as being 110 mm - measured without the main spring. The oil volume is stated as being 520 cubic centimetres. You can visit www.ohlins.com/support/manuals/motorcycle/owners-manuals/ but it's a bit 'messy' finding your way around/what you want and not every bike/model is there but it's worth having a hunt around. Hope that this helps!
Bear with me, I'll see if I can find an electronic copy, it's on a memory stick (somewhere), if not I'll scan and upload it...
Just to let you guys know, I ordered some replacement seals from fleabay and 2L of 7.5w silkolene fork oil, the ohlins spec sheet says 520cc per leg, so I’m covered. I set about stripping the forks down, after watching a YouTube vid from the Ohlins guy showing how it’s done on a 996, really helpful easy to follow procedure. fitted the new seals and upon reassembly noted that the tube was really difficult to get back into the leg, never having done this before I assumed it was normal and carried on. Same with leg no2. Set about filling them with oil and setting the correct level and fastened the tops back on. I didn’t need the 2nd litre as they took a total of 990cc (sods law) Anyhow, feeling rather smug at my achievements I started to pump the forks to see how they felt, at this point I noticed a ring of oil being left behind after each pump, no matter how much I wiped and cleaned the oil reappeared...... gutted to say the least. So after a phone call to bg motorsport at silverstone I bought a pair of gen seals which were 30 quid as opposed to 12 for the non gen. Repeated the above to replace the seals again and the 2 halves of the fork went back together as they should, no fuss. So I have successfully done the job,eventually, and used the 2nd litre of oil, and learned a valuable lesson in that if you buy cheap, you buy twice, thanks for the help and information chaps, mot time next week
