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Front hub /fork problems
Posted: Tue Apr 03, 2018 1:57 pm
by TexasUK
I've rebuilt a newly supplied set of forks and a new hub, but am having a problem with the fit of the hub in the links. It seems as if the drum brake stub on the fork link is too long, that means that there is a large gap between the inner axle nut and the link on that stub side, but no room on the other side. Almost as if the hub has been shifted too far over by the drum stub on the link.
Could I ask if this is normal, and that a standard way of curing the problem is to grind away some of the stub to allow the axle nut on that side to be closer to the link end, and so provide more clearance on the other side? One thing that hasn't been changed is the link or the backplate. Maybe there was a dearth of washers on that side to space out the inner axle to take up the space? But then the hub won't easily fit between the links.
If I did this, which would of course shorten the thread available to bolt the axle to the links on that backplate side, would I also have to bend the forks a little to increase the space between the links? And is that even a good idea?
I cannot see any difference in any of the components that I've rebuilt, although I must admit I didn't look carefully at it before stripping. But I'm sure that the wheel at least turned easily enough. Ramming it in now and tightening the axle bolts up locks it up solid, as expected I guess..
Re: Front hub /fork problems
Posted: Tue Apr 03, 2018 2:39 pm
by wrecklessrobbie
TexasUK wrote:I've rebuilt a newly supplied set of forks and a new hub, but am having a problem with the fit of the hub in the links. It seems as if the drum brake stub on the fork link is too long, that means that there is a large gap between the inner axle nut and the link on that stub side, but no room on the other side. Almost as if the hub has been shifted too far over by the drum stub on the link.
Could I ask if this is normal, and that a standard way of curing the problem is to grind away some of the stub to allow the axle nut on that side to be closer to the link end, and so provide more clearance on the other side? One thing that hasn't been changed is the link or the backplate. Maybe there was a dearth of washers on that side to space out the inner axle to take up the space? But then the hub won't easily fit between the links.
If I did this, which would of course would shorten the thread available to bolt the axle to the links on that backplate side, would I also have to bend the forks a little to increase the space between the links? And is that even a good idea?
I cannot see any difference in any of the components that I've rebuilt, although I must admit I didn't look carefully at it before stripping. But I'm sure that the wheel at least turned easily enough. Ramming it in now and tightening the axle bolts up locks it up solid, as expected I guess..
Your probably better trying to put a picture on here. Then i think people will be able to advise you.
I recently started using tapatalk. Makes it easier to post pictures.
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Re: Front hub /fork problems
Posted: Tue Apr 03, 2018 4:30 pm
by HxPaul
Do you mean that the fork link peg that locates in the slot in the hub backplate is too long or too big in diameter.Theres a picture in the second edition of sticky's manual on page 226.
Re: Front hub /fork problems
Posted: Tue Apr 03, 2018 4:44 pm
by TexasUK
Soon as I get back from work I'll add a few shots. Thousand words and all that
Re: Front hub /fork problems
Posted: Tue Apr 03, 2018 11:10 pm
by TexasUK
Re: Front hub /fork problems
Posted: Wed Apr 04, 2018 2:29 am
by Grumpy225
There is suppose to be a nut on the out side of the hub between the link and hub.
Re: Front hub /fork problems
Posted: Wed Apr 04, 2018 6:37 am
by TexasUK
That's right, and on the right hand side in those photos there isn't enough space for one. While on the left side there is a gap of about 3 nuts width.
That's the problem, if I force it in with a nut on either side (and it takes a fair amount of force to get in) then I will have to pack one side a lot, and when I tighten the dome nuts to hold the axle in it puts too much pressure on the backplate (because of the stub on the left link) and locks the wheel up.
Now if that kind of tolerance is normal for a Lambretta that at least helps me understand the problem, but I doubt it should be like that. I'm thinking I might have to take a big bar and lump hammer to the fork ends to twist and adjust them, but wanted to check if that is a common problem.
If I do have to then I have to assume I've been sold a set with the problem already, which I'd like to think isn't the case as it was someone with a good reputation.
Re: Front hub /fork problems
Posted: Wed Apr 04, 2018 9:11 am
by garry inglis
Definitely needs a thin nut you buy them especially for the front hub also are you sure there series 3 fork links and not series 2 which are different
Re: Front hub /fork problems
Posted: Wed Apr 04, 2018 9:14 am
by HxPaul
On all of your photos you dont show the locating peg on the links,or the slot on the hub for it to slide into.
Your supposed to slide the hub so that the peg on the link locates in the slot on the hub,you then rotate the hub so that the links locate on the axle.
Re: Front hub /fork problems
Posted: Wed Apr 04, 2018 9:17 am
by garry inglis
garry inglis wrote:Definitely needs a thin nut you buy them especially for the front hub also are you sure there series 3 fork links and not series 2 which are different
On the first pic I have 35mm from the top hat of thread and 27mmon the other side this is a series 3 front hub
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