Jet 200 forks too short

[ROClarke]

Just started a dry build using a Jet 200 frame dated 1976 by Rich and a NOS set of forks with the 9mm studs to take the larger shockers.
The ball race at the top of the frame is all the way into the frame and the race at the bottom is fully in as the dust shield is tight against the bottom of the frame.
When I insert the forks into the frame I can get the top ball race nut on OK but there is not enough thread showing after this to take the tounged washer and lock nut comfortably only about half the width of the lock nut thread showing if the washer is used.
I could not fit the washer or look out for a thinner one.
Is this normal ?

[Fast n Furious]

PM sent.

[ROClarke]

Thanks Pete.

[ROClarke]

Really frustrating as the forks are correct length according to Sticky’s latest book.
Looking at extending the forks by 15 mm appx by inserting a sleeve and welding back together.
I just don’t see another way around it

[Storkfoot]

I don’t know the answer but I had a vague recollection of a post about fork lengths in the distant past. I think this was it.

viewtopic.php?f=10&t=1328&p=9410&hilit=Forks+lengths#p9410

[ROClarke]

I don’t know the answer but I had a vague recollection of a post about fork lengths in the distant past. I think this was it.

viewtopic.php?f=10&t=1328&p=9410&hilit=Forks+lengths#p9410

Thanks mate but my forks are the correct length as the link you sent suggested.
I might PM the author to see how he got on.

[gizmo]

I don’t know the answer but I had a vague recollection of a post about fork lengths in the distant past. I think this was it.

viewtopic.php?f=10&t=1328&p=9410&hilit=Forks+lengths#p9410

Thanks mate but my forks are the correct length as the link you sent suggested.
I might PM the author to see how he got on.

Annoying one for you. If frame not been tampered with and forks spot on length it's an odd one. Might be worth giving buzz solomoto a ring and ask if he's ever come across it. Simple thing. Some frame dust covers are too deep. Forks not hitting on this and not going fully up by any chance

[Warkton Tornado No.1]

Due to the fact that I didn't do a proper dry build I had a similar problem on an SX.

Somehow, I managed to get the forks set up - probably by slimming down the OEM race etc - but then the next issue is the area left for clamping the headset. I recall widening the slot for clamping bolt & think I fashioned some kind of extension beyond the fork top so that the clamp didn't distort through not having enough base on which to seat.

It was a lot of hassle, but it did work....

[ROClarke]

I don’t know the answer but I had a vague recollection of a post about fork lengths in the distant past. I think this was it.

viewtopic.php?f=10&t=1328&p=9410&hilit=Forks+lengths#p9410

Thanks mate but my forks are the correct length as the link you sent suggested.
I might PM the author to see how he got on.

Annoying one for you. If frame not been tampered with and forks spot on length it's an odd one. Might be worth giving buzz solomoto a ring and ask if he's ever come across it. Simple thing. Some frame dust covers are too deep. Forks not hitting on this and not going fully up by any chance

Yes mate,I did at first think it was an issue with the bottom race or dust shield,so destroyed the new cover to the race out and refitted the race with no cover,no difference,bugger !
I might give Buzz a call as you suggest.

[Warkton Tornado No.1]

Having given this issue some thought, if I were to encounter the problem again.....

The bearing race-way can definitely be thinned down considerably. Any significant load is taken by the lower bearing & the top set is there primarily to stop the forks dropping out! That said, the top locking nut will ensure integrity with it's contact area with the fork thread. However, that too could afford some adjustment IMO, although it's worth knowing that the KM nuts that the likes of FAG, SKF etc make utilise the same thread. Consequently, the special multitab washers that are also available will also fit & have the benefit of being thinner than the OEM washer. As it say's on the tin, multitab means that there are many tabs, so a tab can be bent upwards to lock the top locking nut whilst another bent downwards to lock the race-way in the instance that the spanner flats had been removed. If using such washers, beware that cables & wiring need to be kept clear as they will get sawn through! There goes the voice of experience

Obviously, following the same process, I personally wouldn't have too many misgivings about slimming down any of the bearing components, even those that fit in the frame, though the top set do less work & are more accessible.

Ultimately, the concern is having the forks turn nicely in the frame &, once established, that setting be maintained.

I hope you can understand my thought process but am aware that I probably do too much thinking 'outside of the box' but if owning a Lambretta is not a challenge, what are we all doing here?

[ROClarke]

Having given this issue some thought, if I were to encounter the problem again.....

The bearing race-way can definitely be thinned down considerably. Any significant load is taken by the lower bearing & the top set is there primarily to stop the forks dropping out! That said, the top locking nut will ensure integrity with it's contact area with the fork thread. However, that too could afford some adjustment IMO, although it's worth knowing that the KM nuts that the likes of FAG, SKF etc make utilise the same thread. Consequently, the special multitab washers that are also available will also fit & have the benefit of being thinner than the OEM washer. As it say's on the tin, multitab means that there are many tabs, so a tab can be bent upwards to lock the top locking nut whilst another bent downwards to lock the race-way in the instance that the spanner flats had been removed. If using such washers, beware that cables & wiring need to be kept clear as they will get sawn through! There goes the voice of experience

Obviously, following the same process, I personally wouldn't have too many misgivings about slimming down any of the bearing components, even those that fit in the frame, though the top set do less work & are more accessible.

Ultimately, the concern is having the forks turn nicely in the frame &, once established, that setting be maintained.

I hope you can understand my thought process but am aware that I probably do too much thinking 'outside of the box' but if owning a Lambretta is not a challenge, what are we all doing here?

Thanks for the great tip about the thinner washers,have you got a link to where I could get some.
Having said that the additional length required would not have been achieved by your very good suggestions I am afraid so yesterday we committed the cardinal sin and took a band saw to the forks just under the thread so as not alter the full steering lock lug.
We then machined a sleeve to extend the forks,inserted this in the forks and welded them up,sorted !!