Will's '75 Commando custom restoration

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I sent the rear disc out for Blanchard grinding and drilling; I didn't do it myself, so I don't have the pattern for it. The client sent me the front disc already drilled, so no pattern for it, either.

I can measure the spacing as closely as possible with my plain steel caliper, that's as good as I can do at the moment.

It appears that the drilling on the rear disc can easily be matched to the front with 3 additional holes per repeating pattern, (two in the opposite angle, between patterns, and one above the "V" that is produced by opposing patterns); if the client wants it done, I'll pop it off and sent it out, too.
 
Okay! thanks GrandPaul... if you could do some measurements that would be great!!!

Also if you please could take another pic of the front disc
at close up. may help too.

Thanks mate!

Brewer.
 
Brewer, both those units appear to be done by DBR disk Brake Reconditioners. Their Phone is 618-344-7683 19 West Scates Caseyville, Illinois 62232
He has done several dozen for us here in Michigan. None have broken from drilling but he has return a few that were cracked before they were sent to him.
 
Yep, good eye Greg. He also turned one for my 75's rear disc that was too thin for the spec to use on the front. Good folks.
 
Good point, Ludwig. Thanks.

The big stumbling block is designing a proper bellcrank/mastercylinder mount that will fit in the limited space and allow enough space for a cable and adjuster. Then convince a buddy with more fabricating skills than me to make it for me.:lol:
 
I think I should have started a new post here as I see this is going off topic. Seeing your photos GP of your rear brake got me into this tangent. Let us know if we should bug out to a new thread with this rear brake talk, you're doing a great job with your build on this thread and thanks for that.


Ron L said:
To convert my 72 commando to a rear disc looks like I need a hub, spokes, caliper & hose, cylinder and foot control with mount. It looks like the caliper mount connects to the axel and shock bolt and the swing arm is unaltered.
Click to expand...

RennieK,

I have done this on my Interstate. You will also need a Mk3 swingarm or do extensive rework of the stock one. Forget using the Mk3 mastercylinder, footpeg, etc. because you will then need a Mk3 inner and outer gearbox cover, the crossover shaft and either convert to a Mk3 inner and outer primary or modify your early style.

The more you get into this conversion, the worse it gets. I ended up mounting a small (old Airheart) mastercylinder behind the frame plate and above the rear fender. This one had a bell crank and with a little fabrication I made a cable mount and operated it from the stock left side brake cable. I did it because I had a Mk3 cradle, swingarm, and wheel in the parts bin.

The end result was more unsprung weight and marginally better brake. I have since converted to a smaller, lighter Brembo disc with a Brembo caliper to match the front. I'm not really happy with the ratio of the master cylinder, so I'm trying to figure out the best way to mount a Brembo rear master with remote reservoir. I have to design a bellcrank to operate it, but it shouldn't be too tough.
Click to expand...

Thanks Ron L for your info.
I have a caliper and rotor from a front end but that's it. I get the feeling I may as well start from scratch with a complete rear disc set up from some other modern machine as try to adapt what I have. I'll have to hunt down a 1975 norton locally just so I can see what the stock rear disc set up is all about.
 
It can be done without too much trouble, try modifying the frame for a monoshock rear and 636 Kawasaki Upside-Down front end.

The rear brake uses a rear axle spacer root for the torque arm plate that slots into the right side rear shock bottom mounting bolt. Piece of cake to fab up one that will work. You will need a '75 rear wheel unless you can fab up a hub adapter that mates to the inside (behind the knave plate) of the right side of a drum brake hub; not all that hard either.

The last bit will be master cylinder fitment to whatever peg system you are using. Excercise your brain.
 
I thought it should be fairly straight forward after seeing your photos of the lougheed brake but then Ron mentioned needing the MK3 swingarm or doing extensive reworking on a stock one. So Ron I take it this is necessary for strength but not necessary to get it to fit.
Thanks for the great photos ludwig, what a nice neat setup on the caliper mount.
 
First draft of proposed custom oil tank pattern & mounting, and battery relocation plan. Have not yet devised mounting for either item, but it won't be rocket science. The oil tank fabrication will use the inlet & outlet plumbing off another old used tank that I have, and should be about 95% of original capacity (no worries). Battery will be much smaller than original as no electric starter will be mounted (also gives up some of it's space to the new battery location.

It gives the client his desired "clear space" behind the engine, stretching the oil tank across the width between the frame tubes. The rear fender will need to
be cut short, and the oil tank will act as a lower half of the fling guard.

Will's '75 Commando custom restoration
 
GrandPaul,
Are you planning to mount the battery to the engine plates? I would think the vibrations there would not be good for it.

Could it be possible to replace the entire battery box with an even lower slung tank whose top would be substantial enough to double as a battery mount?

Since you obviously are not replacing the electric starter, you won't need a very large battery, so you might be able to save room there.

Is the desire for "clear space" aesthetic or does the client have an idea for using this space?

This is turning into a very interesting build!
 
I'm thinking of modifying the original battery tray with a drop center just big enough to hold the smaller gel cell, with the rear section adapted to tabs for rubber mounting the oil tank.

Pure aesthetics on the client's list for the clear space.
 
GP,

Have you given any thought to one of those combination tanks?

Will's '75 Commando custom restoration


Then you could mount a small battery in the horn location and have all kinds of space.
 
GrandPaul,
That version is for a featherbed frame, which, of course, doesn't have the big spine running through the tank. To do this with a Commando tank you would probably need to use one side of an Interstate style tank for oil and the other gas.

By the way, that is a Tank Shop tank. Broken link removed
 
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Yes, I found that pic on the tank shop's website, and it is for a featherbed, but one could do a combi tank for the commando frame, perhaps side-by-side.

...or use the frame itself, ala Triumph

just throwing ideas out there :)
 
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