Rear Spring Boxes rubbing.

[youngjohn]

The rear spring boxes on my Comet are bending down over slightly in the middle (like a banana shape) and causing the top of the stainless inner shrouds to get rubbed by the edge of the painted outer shrouds. Can anyone tell me what the problem is likely to be, or is this normal?
Thanks.

 

[Len Matthews]

It could be that the studs that pass through the rear frame and upper frame members are seized.The springboxes must be free to pivot to accommodate for suspension movement. The sleeve in the rear of the oil tank must be free in it's bushes and must project slightly either end so when the nuts outside of the eyebolts are tightened everything still moves. Also, leave the eyebolt locknuts loose until everything else has been tightened. Hope that helps.

 

[clevtrev]

The rear spring boxes on my Comet are bending down over slightly in the middle (like a banana shape) and causing the top of the stainless inner shrouds to get rubbed by the edge of the painted outer shrouds. Can anyone tell me what the problem is likely to be, or is this normal?
Thanks.

Absolutely normal. If you can find some original springboxes that have done a lot of miles, you will find that one side will be worn to a wafer thickness. This is merely the action of the rear frame moving through an arc.
PM me for a solution.

 

[Bill Thomas]

Hello John, I think you will find most of us have some scuff marks, What Len says is right but also that last bit you nip the nuts up tends to tip shrouds, If you can push the shrouds the other way as you nip the nuts up it might help.Talk to Trev' he might have some sort of P T F E buttons, Which it needs. I belled the ends of the outer top shrouds years ago but it wasn't perfect, The joys of a 1950 Bike !! Good Luck Bill.

 

[vince998]

Hello John, I think you will find most of us have some scuff marks, What Len says is right but also that last bit you nip the nuts up tends to tip shrouds, If you can push the shrouds the other way as you nip the nuts up it might help.Talk to Trev' he might have some sort of P T F E buttons, Which it needs. I belled the ends of the outer top shrouds years ago but it wasn't perfect, The joys of a 1950 Bike !! Good Luck Bill.

Reading through Forty years on the other night, i came across an article from Ron Kemp on page 14 (article Nr 58 or to be found in MPH 207)) where he explains a "fix" for this problem involving 3 equally spaced indentations around the circumfrence of the outer shroud.(Sounds like a "battle damage repair" to me )

I´m experiencing the same problem on the front where the outer spring boxes have become alarmingly thin where they contact the inner.
I did hear of a mod a couple of years back involving PTFE bushes pressed into the outer spring boxes. Maybe this will work for the rear? not sure where to source them though.

 

[Bill Thomas]

Hello Vince, Vin-Parts did the mod you say a few years ago on the front. I don't like the other mod' with the indentations. Come on Trev tell us all your solution, It has anoyed me for 45 years, Now it's just the Wife !! Cheers Bill.

 

[clevtrev]

I did hear of a mod a couple of years back involving PTFE bushes pressed into the outer spring boxes. Maybe this will work for the rear? not sure where to source them though.

Try Hayling Island, I use nylon now, I found it better, and cheaper.
Only been making them for the last thirty plus years.