Hitchcocks Forum

I fitted new bushes and seals to a set of Norton forks on a 1A Inter about 6 months ago and the bike has been sitting here on the centre stand. A couple of days ago I decided to move it and get it running again ready for our upcoming AGM. Took the bike off the centre stand and the forks compressed down. With the brake on and rocking the bike the forks do still have some bounce but are probably an inch and a half too low. Before I pull it apart any thoughts?

Apart from "stiction" where the the upper bronze bushes have become dry. My Norton forks are always compressed, possibly as much as an inch or more when the weight of the machine is on the forks. The only other possibly reason is that there is some form of vaccuum created and with the new bushes and seals the vacuum can not be equalised. There is no way air can get back in the sealed mechanism unless you release the two top chrome nuts with the forks fully extended (leave the damper rods on) to let air in, then screw back the nuts fully and try again. Apart from that there is nothing that can go wrong with them.

Norm, Les the most likely causes are firstly corrosion on the stanchions which then prevent the free movement of the forks, particularly if they have been standing for 6 months. This is less likely to occur after the bushes etc have bedded in. Secondly the fork legs may not parallel and true in the top and bottom yokes. Slacken the pinch bolts, apply the front brake and keep it on, and then pump the forks up and down a few times then with them fully compressed and the brake still held firmly on get someone to retighten the pinch bolts. The vacuum theory is not valid as these forks are sealed when properly assembled and the damping action automatically equalises the air pressure. Roadholder forksare just not sophisticated enough for this to be a problem.

I was assuming Norman knew what he was doing when he assembled them, lubricating all the parts on assembly and would have had them working normally and correctly before leaving them for 6 months. As said by me, there is little that can go wrong with Roadholders, and if Norman still has normal free movement which he said he has then having the forks not free or parallel does not explain why the forks are settling at too low a level. The position of the fork when loaded is soley set by the load on the internal springs....just like a spring balance, a certain load will create a certain deflection and if free without will result in the same deflection from full extension. When the forks are working correctly and are compressed, there is air compression as it cannot escape but on extension the compression is relaxed this occurs continuously. If for some VERY ODD reason, air on compression has been expelled, perhaps from stiff oil seals and then the seals have sealed on extension, the created vacuum WILL exert some negative effect from the fork extending back to the same normal length. Obviously this does not happen when the fork is working normally, but then again when the fork is working normally the same ride height is always achieved for any given weight. If however Norman has described the symtoms incorrectly as might be the case here, then one can only hazard a guess what might be the reason, and as also said by me, I have never known this problem ever to exist. So if Norman has assembled the forks incorrectly, then they would have always been like this from his initial rebuild of them, and should have said.

Thanks Les. Mike I think you are on the money, now you mention it I didn't fit the front guard a mate did, and I remember seeing him have trouble with it. It had new stays but the original guard which didn't fit too well and I bet he ended up forcing it to fit and this will be making them stick. I'll pull the guard this morning and all should be good

Ok now on closer inspection it appears that the dodgy bros who fitted this fork setup (and it was a real roughie, backyard yankie roughneck job)fitted a set of standard roadholder forks. Problem arose once we fitted the correct headlight ears and other pieces and new gaiters.(it didn't have gatiers fitted).Once off the centre stand the gaiters compressed up and the bike had a forward lean.On looking at the parts books I have a feeling that it might be missing the damper tube extension part number 50054. Does anybody know what this part looks like and would it lift the forks by 1"to 1.5" which seens to be about the amount the forks are compressing too much by.