F: Frame Snapped Rear Mudguard Strut

[CarlHungness]

I have 1. 1/4" pivots on my Dog leg levers, I thought they would give more leverage,
But I have been told I am wrong,
Just saying my brake is better for me,

I also have a disc setup I " could " put on if I wished,
But OK for now.

I respectfully dis-agree in the "Ok for now" if the bike is ridden in traffic. The best mod I ever made was putting discs on my Shadow, and prior to that I cloned the stopping distance test ran 'back in the day'. I flat spotted a tire
doing it and basically over-shot the point I REALLY wanted to stop at by about 100'. No, the stock brakes aren't OK for today's riding in my opinion. Or, if you've never had to do an emergency stop, you won't believe me.

 

[erik]

Here in Germany you can not fit discbrakes in a vintage motorcycles becausof the TÜV (mot). With the superior Speet brake or the Schmitz brake you have the outlook and they do the job.To my mind Fitting discbrakes to a vintage motorcycle is a little bit like fitting a pacemaker to a mummy ! Regards Erik

 

[Bill Thomas]

I respectfully dis-agree in the "Ok for now" if the bike is ridden in traffic. The best mod I ever made was putting discs on my Shadow, and prior to that I cloned the stopping distance test ran 'back in the day'. I flat spotted a tire
doing it and basically over-shot the point I REALLY wanted to stop at by about 100'. No, the stock brakes aren't OK for today's riding in my opinion. Or, if you've never had to do an emergency stop, you won't believe me.

I know what you mean Carl, But life is a risk, Riding an old bike will always be risky,
If it worried me that much , I would sell up and buy a new BIKE.
I have one Special Vincent with disc brakes front and rear and in the rain I find that dangerous,
With the lag drying the disc off,
I raced Vincents for 17 years, And have had a few problems on the road and on the track in 57 years,
They now tell me Motorcyles are dangerous, Gulp.

 

[CarlHungness]

Here in Germany you can not fit discbrakes in a vintage motorcycles becausof the TÜV (mot). With the superior Speet brake or the Schmitz brake you have the outlook and they do the job.To my mind Fitting discbrakes to a vintage motorcycle is a little bit like fitting a pacemaker to a mummy ! Regards Erik

Go ask the well-respect Ian Savage about fitting disc brakes. He had an emergency stop one time, couldn't make it, and was able to dive to the side. He wound up nearly two car lengths from where he wanted to stop. He then installed the discs. If discs had been available the factory would have installed them. If memory ser ves correctly the auto racing world saw discs in the mid-Fifties so they weren't in popular usage when out bikes were made. I'm sure the Speet brakes work well and (probably) the Schmitz ones as well. Have never seen the Schmitz and I'm an avid MPH reader. Looks be dammed, if it'll save your bacon, install it whatever it is.

 

[brian gains]

so scanned through this thread and it has gone from broken stay to fitting disc brakes !?.
Can't understand that the condition of roads should have contributed; HA !, please folks there are web site thingies where you can notify of potholes etc, the condition of roads are a bloody disgrace, use it.
Regarding fractured stay, I was told years ago to reinforce flattened bolt fixing end with an internal smaller diameter tube running inch or so beyond flattened section. Never tried it but have kept it in mind should the occasion occur. Just sayin'.

 

[danno]

Just picking this up again. The reason for the broken stay and hole was probably down to the lower mudguard bolt being lose which has also caused the mudguard alloy to break at the mounting near the shocks.
It’s a bit of a mess really and the bolts aren’t easy to get at to tighten.

The suspension and rear end does seem to be improved now the Craven rack is off. This may have contributed to the breaks too. Hopefully it won’t take too long to fix plus I need practise with the ‘quick’ rear wheel removal.

 

[danno]

You can repair the alloy guard with one of the low temperature alloy "welding" kits, or if it is original "Birmabrite" then use the alloy from a very early Land Rover as filler as I believe it is the same composition.

I think the bike had steel mudguards until it was restored in the 90's.
Not sure how to tell if these are alloy or Birmabrite. I'll have a go at fixing it with alloy sheet on the underside then fill using a Durafix alloy weld kit.

 

[danno]

Have got the mudguard off. A few of the holes have stretched over the years so will have a go at repairing.
The largest is where it’s bolted to the rear frame.
I’ll probably get a new stay (FT22/4) and strip ((FT152).

 

[Simon Dinsdale]

I have a theory about why rear mudguards break around the two holes where it fits to the front of the RFM. When you pull the bike onto the original Vincent rear stand the pulling force transfers through the lifting stay, through the mudguard hinge and then through the mudguard to the RFM. The rear chainguard will help stop some pull but as you are initially lifting the bike upwards then the force goes through where the mudguard is bolted to the RFM. I suspect with a lot of bikes are using the Dave Hills center stands today and not the rear stand so the rear mudguards will see less stress.

 

[danno]

I suspect with a lot of bikes are using the Dave Hills center stands today and not the rear stand so the rear mudguards will see less stress.

This bike has a D type centre stand fitted. Around the same time as the mudguards. The original rear stand hasn't been used for decades.
Fitting a used replacement mudguard would save time.