Help! Upper Yoke Fixing Bush Won't Budge

[Fausto]

Just to say that it's no suprise that the bearing lock nut was looser than expected. It's probably just due to the bearings bedding in from new.

Sorry but can't help with the other problem other than to suggest that you just leave things alone

[Falcopops]

Damn Andy, you do seem to try to make these jobs even harder than they need to be.

The collar nuts shouldn't be on too tight and since they're hidden from view a blunt drift and a hammer will see them loosened with no harm done.

Nearly forgot to mention, you'll need to bend a couple of the tabs on the washer between the collars before undoing.

Good luck

[D-Rider]

Wow you are up against it today

Cant help with any info... but if you need then I do have a spare top yoke for you. It is very manky but since you are stripping it anyway that wont matter. The best part is - I KNOW it fits cos it was on mine before the mankyness irritated me to buy another. You want it? I cant post it tomorrow so with you on Thursday?

Cheers Dominic - much appreciated.
The plan at the moment is to take the yoke to a local engineering works and get it bored out to 33mm from it's current 22mm. I've checked all other important dimensions and they look OK.
If that doesn't work or they mess up the boring then I'll take you up on your kind offer - but hang fire for now - I'll see whether I can get the current one fixed.

There is another way, of course, and that is to shim the Ohlins fork legs into the Aprilia/Marzocchi yokes. The Ohlins fork legs are only 1mm diameter less than the Marzocchis, I believe?

The simplest way would be to take one can of beer (choose your favourite, obviously), drink the contents, then set about the can with a pair of tin snips to make 4 strips of can about 15-20mm wide and 150mm long. Then use the strips of beer cans as shims to pack out the fork leg/yoke interfaces...

Yes, Graham, you are right, it can be shimmed - I've just made some shims for my clipons which have the same issue. That said, I'd sooner get the yoke to fit properly without shims if I can do so (but it's another backup plan should I need it).
BTW for the record, the Marzocchi forks are 53mm diameter and the Ohlins (at the top yoke) are 51mm - the difference is 2mm requiring 1mm shims (or 0.8 / 0.9mm are easier to fit).
Thanks for your input though - again appreciated .... I'll certainly take heed of the beer idea and do the drinking bit .... though knowing how things are going for me on this project, I'm bound to end up with a bottle rather than a can!

Just to say that it's no suprise that the bearing lock nut was looser than expected. It's probably just due to the bearings bedding in from new.

Sorry but can't help with the other problem other than to suggest that you just leave things alone

Good thinking ..... however it's not the nut that tightens on the bearing that's loose, it's the locknut that sits on top. Anyway, when I put it all together, I'll get it tightened down right.
Cheers.

Damn Andy, you do seem to try to make these jobs even harder than they need to be.

The collar nuts shouldn't be on too tight and since they're hidden from view a blunt drift and a hammer will see them loosened with no harm done.

Nearly forgot to mention, you'll need to bend a couple of the tabs on the washer between the collars before undoing.

Good luck

Hi Dale - yeah I know about the tabs thanks. The nuts won't be an issue to remove (he says recklessly) - I do need to make up a peg spanner though so that I can torque it down right. It's a slightly complicated process - torque down very tight, slacken off and torque to a lesser value - then do up the locknut. I need to make the peg spanner from a 1/2" drive socket so that I can fit it on my torque wrench to get it done up correctly.


Once again, thanks to you all. I'll keep you updated with progress.

[D-Rider]

..... so ........


I've been to see how much it will cost to get the hole bored out on my Ohlins yoke.
I'm told, depending on how long it takes ..... £40 to £50


Dominic .... you have a PM.