MOT Failure

[Duncan R]

I decided to take my bike for MOT yesterday, it has been off the road for ages. I knew it was a bit premature maybe but  at least  if it failed I would have a list to work from. All the usual stuff I checked before hand and everything seemed to be in good working order.

I had put some new brake shoes in the front but on the ride to the MOT station the brake did not feel any better than it was before (almost useless) Handling felt very strange(put this down to the old tyres - new ones on order)  anyway it failed on the following points.

Useless front brake (expected)
Wheel alignment(explians the strange handling-a bit worrying)
Left hand silencer mounting(fixed)
Headlamp to low (fixed)
hairline crack in the front barke plate(gone back to the shop for the welding today)
Lock stops inaffective(steering damper had been put together wrong - fixed)

I am now worried I have a bent frame - I have realigned the wheel adjusters today,could they have been that far out as to cause serious problems?

The new brake shoes look like they have only about 50 % of contact with he drum, there is no judder and the drum has a bit of grooving but nothing serious - any thing else that can be done to improve it? it is the 8" half width SLS

Thanks

Duncan

[bsa-bill]

slacken the nut on the brake pivot, pull the brake on hard then tighten the pivot nut, see if there is an improvement
Another modification is to make the shoes floating, this involves filing the pivot end of the brake shoes from circular to an elongated slot, the idea is the brake will self centralise when  applied.
Some photos would help explain this better but sorry I have not time at the moment

[Duncan R]

Thanks Bill, I will give it try when I get the brake plate back. There seems to be a distinct lack of friction.

[bsa-bill]

Of course I forgot to mention new shoes will take a little while to bed in, I usually have mine set to rub slightly all the time and adjust until they bed in.

[Duncan R]

I am looking at getting the drum skimmed and oversize shoes with decent lining material, I just don't think these shoes are going to bed in. I have a newish cable that has been oiled and the pivot moves freely. Back brake has plenty of bite to it.

[iansoady]

Wheel alignment(explians the strange handling-a bit worrying)

Duncan

My local MoT place has stopped checking alignment - he says it's because so many single sided swinging arms were out and of course there's no easy way to rectify them. He says DVLA sent out an instruction to that effect.

Not saying you shouldn't check it yourself of course.

It's surprisingly easy to get the rear wheel quite far out.

[Duncan R]

I am taking it down to Maidstone Motoliner to get them to check it out. If it is bent the Motorliner jig only requires the tank,seat and exhaust system to be removed before it can be bent back into shape.

[wilko]

If you can find some asbestos shoes you will have your brakes working like they were meant to be. Ask me how i know!

[Duncan R]

Hi Wilko,

The shoes I have are made in Taiwan - I have used them before in japanese drums and they worked fine. Drum is being cleaned up at the moment, so will see how that works

[Triton Thrasher]

slacken the nut on the brake pivot, pull the brake on hard then tighten the pivot nut, see if there is an improvement
Another modification is to make the shoes floating, this involves filing the pivot end of the brake shoes from circular to an elongated slot, the idea is the brake will self centralise when  applied.
Some photos would help explain this better but sorry I have not time at the moment

Something like the above sounds very likely to help. On a Norton SLS brake plate, you enlarge the spindle hole for simialr reasons.

 Also, it's worth checking whether the brake works better when you wheel the bike backwards. That would indicate the trailing shoe touching the drum first. If the two shoes on a BSA are identical, you can swap them over.

If the drum has a slight trough worn into it by the shoes, you can chamfer the sides of the linings to let them into the trough.

[Duncan R]

Hi Triton,

Thank you for the tip. I get the wheel back monday,spoke to Rob at Hagons and he said it had skimmed up nicely with only 2 cuts which totalled 10 thou, all the grooves gone and heavy glazing removed. Hopefully this will give me a working brake.

[Duncan R]

Bike went for re-test yesterday and passed. Huge improvement with the front brake, although at  first it was still the same. Had to take the long way to the test and do about 15 miles around the lanes to bed the shoes in. It just got better and better, You can actually feel the forks dive and shoes biting on the drum, I can now use just the front barke under normal conditions.

Got the wheel alignment right, so no bent frame. I only noticed how notchy the head race bearings were when I had the front wheel out, I changed them for ball races on sunday. It handles really nice now, even with the crap tyres

Thanks for all your input

[a10 gf]

Congrats, always nice to read some good news, and a confirmation the (very important) front brake can be improved if the right work is done.

[bsa-bill]

Nice one Duncan

[Duncan R]

Thanks guys - to be honest I was getting a bit fed up as I was finding more and more faults. But with the wealth of knowledge on this forum there was no need to panic!