Fork Rebuild

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Tim

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Feb 4, 2009
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I am rebuilding the forks on my 1973 Commando 750. Have cleaned all parts, replaced fork leg, spring (Progressive), bushes, seals and washers (from Old Brits). My problem is that it won't go back together. The steel bush at the bottom of the fork leg doesn't want to slide into the slider. I tapped it in gently with a rubber mallet (about 3"), but it would not slide and I was afraid to score the ID of the slider, so I pulled them back apart (difficult). The new steel bush is 0.005" larger OD than the old bush. I considered using the old bush, but it is a sloppy fit and allows a lot of side play. The slider ID measures round. What am I doing wrong? Any suggestions?? This is my first restoration.
 
I don't think you are doing anything wrong, the bushes should all be a sliding fit. I'd get on to the supplier they might have a bad batch.

Cash
 
I had a similar problem. I bought some fork tubes from Walridge where one was slightly larger. Sent those back and got a new set that were perfect. I ordered a Domi-Racer supplied bushing/seal kit from Walridge at the same time I ordered my new fork tubes and the bottom two bushings were larger than the OEM (Norton labelled) set I bought last year. I used the old ones with my recent fork rebuild and they fit perfectly.

Was your bushing kit labelled Domi Racer? if so that may explain it.
 
There was a little talk recently that some replacement parts may be oversized to account for wear on these older bikes. This may or may not be the case with these parts. Frustrating for the consumer if not communicated correctly.
 
I've been finding those to be all over the map depending on supplier, and the wierdest part is, two different sizes in the same Andover Norton parts baggie!
 
OK. I think I'll try the other set of new bushes on the other fork leg and see if they fit. If not, I'll contact Old Brits and see if they have had any similar problems with their fork rebuild kits. Thanks for the help!
Tim
 
grandpaul said:
I've been finding those to be all over the map depending on supplier, and the wierdest part is, two different sizes in the same Andover Norton parts baggie!
Click to expand...

I had two different sized stanchions in one box. Maybe we can get together and make one set of working forks. Ha!

All this mismatched parts business is kind of making sense now that I know there are a few different sources for parts.
 
I never throw anything away.

I build up a lot of rolling basketcases for sale, and often a decent used fork bushing of the correcdt size will more than suffice when replacing one that's had vice-grip teeth gash it up, or cracked from trying to smack it down the tube with a rubber mallet.

A good used bushing that is oversize to a particular tube yu are trying to match can be carefully re-worked to fit properly if it means you'll get to make the weekend rallye. It just means you get to do it all over next week when the correct part finally arrives.
 
I have a set to rebuild andd was working up a monster order for O Brits. Maybe I should call them and get somebody to do a little mic-ing first. Thanks for the heads up.
 
Ive just rebuilt my 72 commando forks. I ordered the stanchions and bush/seal kit from norvil. I found the same problem as you've encountered. It turned out that a little alloy had corroded in the tube top so i carefully got that out. Then on the steel bush, where it had been machined off, it had created a tiny lip. So i carefully sanded each end a little and hey presto! I did work the stanchion with fork oil and the top bush in for a little while just to make sure it all moved smoothly.

Oh and don't over tighten the top nut thing, it cause's the fork stanchion to jam and makes it very stiff lol.
 
Thanks for all the suggestions. Here is what I did. I measured the OD of the old steel bushings and found them to be just slightly smaller than the slider ID. The old bushings were scored, so I polished them using a sisal wheel and black compound. They looked better than the new ones, so I put everything back together with the new fork tubes, upper bushes, seals, washers, large gaiters, and nicely polished sliders. There was a very small amount of play at the top of the fork tube, just noticeable. I think (hope) it will all work.
Tim
 
I've also noticed the I.D. of a new set of lower bushings (kit packaged from Domi-Racer)to be slightly smaller than an OEM Norton set I got two years ago. I used the older ones as I didn't have to fight with them to get them on the stanchions. New ones are going back.
 
Tim said:
I am rebuilding the forks on my 1973 Commando 750...(difficult). The new steel bush is 0.005" larger OD than the old bush. I considered using the old bush, but it is a sloppy fit and allows a lot of side play. The slider ID measures round. What am I doing wrong? Any suggestions?? This is my first restoration.
Click to expand...
Welcome to the dark side.



grandpaul » Tue Jun 02, 2009 4:18 pm
...I never throw anything away...
:lol: :lol: :wink:
 
do many of you who rebuilt your forks replace the legs? Or is only a rebuild kit needed?
 
If you do replace your legs are there any experiences (good or bad) with emgo? I've seen one post referring to lathe work on emgo lowers to enable the bushing to fit properly. Don't imagine this would be a problem with norton standard replacements. Has anyone an idea how wear in the 'oilite' bushing and lower internal fork components could affect dampening?
 
No idea on the drum brake but on all the disc braked bikes the stanction on the disc side gets badly worn on a 90 degree section.
 
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