FF: Forks More Brampton Woes

ogrilp400

Well Known and Active Forum User
Non-VOC Member
G'day All,
Another problem has presented with these Bramptons. This one I have not encountered before but some one in Australia did ring and ask me about this same same problem. Sorry I can't remember who it was. Have a look at the angle of the fork links. The forks are as near as to full extension. There is only a very small clearance between the fork and the stem cross piece. These are new Bramptons What is going on here? I have been for a very short ride and the fork action is very pliable. My guess is that the spring is too long and/or is a sidecar one. Ideas?

Phelps
 

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Robert Watson

Well Known and Active Forum User
VOC Member
Go and look at many sets of Bramptons and see just how many hit the back of the rear down tubes on the stem cross piece.
Any one for a survey?
 

Gene Nehring

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VOC Member
Top nut on most is stamped either 180lb or 160lb. I believe without looking the solo spring should be 9 7/8” long. KTB has all the spring details.
 

davidd

Well Known and Active Forum User
VOC Member
Phelps,

That looks like way to much spring in there. With the stock Brampton unladen the lower link should be no higher than parallel to the road and laden it should look a little "saggy".
1947The_Motor_Cycle_1.jpg


1947SpitfireRapideSmall.jpg



David
 

Albervin

Well Known and Active Forum User
VOC Member
G'day All,
Another problem has presented with these Bramptons. This one I have not encountered before but some one in Australia did ring and ask me about this same same problem. Sorry I can't remember who it was. Have a look at the angle of the fork links. The forks are as near as to full extension. There is only a very small clearance between the fork and the stem cross piece. These are new Bramptons What is going on here? I have been for a very short ride and the fork action is very pliable. My guess is that the spring is too long and/or is a sidecar one. Ideas?

Phelps
Is that on side stand, with a rider on it or on rear stand. It looks way too extended either which way.
 

Albervin

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VOC Member
When you say new> Do you mean Mike Breeding forks? They are the only NEW ones I know of. I have a set of his on my Rap and they are nothing like this. He does buy in the spring and other hardware so it is not down to Mike that it is sitting like this.
 

Oldhaven

Well Known and Active Forum User
VOC Member
My Bramptons on the '48 Rapide have obviously been up against the stem cross piece before and are dented there. I see one new chip in the dent area but when my brother repainted the forks long ago the dent was there then. Also in this picture you can see the white mark or chip where the steering stop is hitting above the rib, so there you have another data point for that discussion.

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I have an 180 pound original spring on it now, but for most of its life since my rebuild it has had a Thornton (Works) spring over conversion, and it also has a Patzke taper bearing conversion to complicate both matters. The Thornton had a 1/2" internal stop added to limit its travel so that it just cleared the crosspiece on full extension, though it could get quite close. This leads me to believe that the standard spring was the culprit during an earlier life. The original spring is constrained at both ends and should limit travel but could extend enough to do this I suppose if the unsprung weight was rapidly accelerated from full compression to full extension during a jump or from a hard dip in the road. Both the Thornton and this spring are close to level when I am in the saddle.
 
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Cyborg

Well Known and Active Forum User
VOC Member
Go and look at many sets of Bramptons and see just how many hit the back of the rear down tubes on the stem cross piece.
Any one for a survey?

One for each column. The one with the dents is closely related to Oldhaven’s.
I just look at the dents the same way as the ones in the touring fenders.
 

oexing

Well Known and Active Forum User
VOC Member
Just thinking, maybe a steel rope inside the spring could help to stop the girder from excessive extension ?

Vic
 

ossie

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VOC Member
my forks only have a very short travel and do get close up on the rear stand they also miss the limit stops side to side.
 
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