Custom Cafe style 72 Commando

baz · Nov 27, 2015

o1racing03 said:
triumph2 said:

The front Wheel is from a Yamaha RD400 and is a straight bolt on. You need only make up spacers for the Norton axle to centralise the wheel and if necessary shim the caliper. The rear wheel is from a Yamaha SR500 and required a bit of machining. It has a cush drive in the hub and a disc brake. I had to machine the sprocket carrier to align the chain. the master cylinder and caliper were from a Yammy Seca I think and is handy because it uses a cable and so I was able to use the stock brake pedal and cable. My memory is a bit rusty on mmthis as I did the work in about 1984.

Click to expand...

I like the idea of a cable actuated master cylinder. I'm curious what you used, Seca came out in 83 and all the early Seca rear master cylinders connect directly to the pedal with no cable

On a 750 seca it's the front master cylinder that is cable operated its the same setup as the early disc braked BMW boxers the master cylinder is under the tank cheers baz

Paddy_SP · Nov 27, 2015

Ken - that's a great pic of your bike - what's the story with the gearbox on it? The cover makes it look very interesting!

lcrken · Nov 27, 2015

Paddy_SP said:
Ken - that's a great pic of your bike - what's the story with the gearbox on it? The cover makes it look very interesting!

The gearbox is a Quaife heavy duty 5-speed. I think it was originally developed for sidecar racers. It had sturdier gears and shafts than the usual Quaife cluster for AMC boxes. After I retired the PR and sold it to a friend for restoration, I kept the 5-speed. A few years ago I used it in the Norton-powered landspeed streamliner we ran at Bonneville. I still have it, and plan to use it in my current MK3 street bike, currently under construction. There's a little more info on it here, but not a lot

production-racer-ama-twins-bike-t10642.html?hilit=daytona production racer

Ken

lcrken · Nov 27, 2015

And here:

monoshock-and-daytona-1990-t8194.html?hilit=daytona production racer

Ken

o1racing03 · Nov 27, 2015

tricatcent said:
http://s901.photobucket.com/user/tricatcent/media/NortonRidingL_zps2064a224.jpg.html

Here is a picture of my Norton with Yamaha wheels. A friend gave me the wheels. It has a MKIII swing arm and rear brake. I had to narrow the Yamaha speedo drive a bit to get it to fit. I guess the RD 400 front end is wider than the Norton one. I used a Kawasaki speedometer. I made an aluminum holder for it so it looks like a Norton one. It is nice not to have to use the Smiths drive on the back wheel. They are not that long lasting.

It handles and brakes really well. I has an 18" front wheel, the only problem I have noticed with that is that the bike is lower. Nortons don't really have much ground clearance anyway so you don't want to lose any. People say these wheels are very heavy, and the bike won't handle right, but try riding behind me and then tell me what you think! I use a 12mm master cylinder on the front brake and no other improvement is required.

I used the standard Yamaha sprocket, which is a lot smaller than the Norton one so with a 19 tooth gearbox sprocket the ratio was the same as a 22 tooth sprocket with the standard Norton one. The standard 850 engine pulls that gearing with ease. I don't see the point of lower gearing on an 850. If you want more acceleration just leave it in a lower gear longer. With the wheel centered I found the rear sprocket was lined up with the gearbox sprocket within .040". I moved the wheel .020 to one side so that both the wheel and sprocket alignment would be within .020". The Yamaha uses the same size axles as the Norton.

The wheels are powder coated. If I did it again I would just paint the wheels. The rear wheel had to be done about three times sanding smooth each time before the finish came out smooth. It was because gas kept coming out of the castings. The gas came from the oil that had soaked into the metal over the years, when the wheels were baked the gas was forced out. With paint that would not be a problem. I think that black and gold is the best color for a Norton. I painted my tank black even though it is made of aluminum. When it comes to color everyone has their own preference.

The bike started out as a Café, with an XR750 seat, but now it has a dual seal and luggage for touring.

Nigel

Don't give up on the idea of powder coating your wheels. The oil on them has little to do with the issue. Out gassing is an issue with any "cast" part and occurs when the metal is heated and the pores open releasing casting debris and gasses that were sealed in the pores as the metal cooled. The solution is to heat the wheel to 475-500* for an hour. This will open the pores and purge them of the debris and gasses. It is at this point you want to media blast the wheel removing all the debris and releasing any gasses that would show their ugly head at 400* cure temp. If it has been subjected to heavy oil contamination then we would out gas the wheel before blasting and then use a Red Oxide Outgas Forgiving primer that is applied to the wheel at 390* where, instead of letting the powder go through a slower melt/flow/cure process, it melts/flows/ and cures in one minute before the outgas issue has a chance to come to the surface. Then apply your top coat as usual. You won't have the OG issue with paint, but you may still have issues if the surface was deeply contaminated with oil or salt. And you end up with a finish with paint that is not as durable or long lasting. I competent coater will know about this issue with cast parts and will deal accordingly, one of the differences between the cheap coaters and the ones that charge what it's worth.

o1racing03 · Nov 27, 2015

lcrken said:
Ian, I posted a couple pictures here of a cush drive I made for a Marvic mag wheel for a Norton monoshock racer:

1973-850-mono-shock-showa-forks-t7974-105.html?hilit=cush%20drive

It's a pretty simple system, but worked well. I had a similar cush drive on my Commando PR, but don't seem to have a good picture of it.

I do have this picture of the bike that shows the rear disk brake setup I used. The swinging arm isn't stock, but I'm sure you could come up with a similar system on your bike. You could also make it work using a MK3 swinging arm, but that's a really heavy setup. If you can fabricate that sort of thing, you can make something much lighter. I don't recall what caliper and bracket I used (It was over 20 years ago), probably something off an early TZ250, but you could find all sorts of calipers on modern bikes that would work well.

Ken

So am I correct in thinking there is a brake fluid line from the caliper all the way up under the tank and then a cable from the tank down to the break pedal?
After some research today I'm thinking of using a DR650 caliper and bracket on the left on routing a hose to the m/con the left near the stock pedal with a 220mm rotor. Just need to weld a slug on the swing arm for forward movement on my Triumph.

I found the answer to my question about the Ducati rotor bolt pattern, they are the same 74mm as a Honda, and apparently about 35 other bikes, so front rotor selection is easy, just need to figure a way to mount calipers on a Triumph fork leg.

Paddy_SP · Nov 28, 2015

lcrken said:
Paddy_SP said:

Ken - that's a great pic of your bike - what's the story with the gearbox on it? The cover makes it look very interesting!

Click to expand...

The gearbox is a Quaife heavy duty 5-speed. I think it was originally developed for sidecar racers. It had sturdier gears and shafts than the usual Quaife cluster for AMC boxes. After I retired the PR and sold it to a friend for restoration, I kept the 5-speed. A few years ago I used it in the Norton-powered landspeed streamliner we ran at Bonneville. I still have it, and plan to use it in my current MK3 street bike, currently under construction. There's a little more info on it here, but not a lot

production-racer-ama-twins-bike-t10642.html?hilit=daytona production racer

Ken

Many thanks, Ken - that's very interesting! I have a Quaife 4-speed wide ratio grasstrack box in my sprint-hillclimber, but unlike yours, although it has very thick main castings, the outer cover is stock AMC. I've only ever seen two of these boxes, and I own the other one too!

Thanks for the links too!

Custom Cafe style 72 Commando

baz

Paddy_SP

lcrken

lcrken

o1racing03

o1racing03

Paddy_SP

Similar threads