More ?s on disk conversion on 71 Commando.

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Jun 11, 2004
I'm interested in double disks at the front. I'm less interested in authenticity. I know about better linings.

Is there a great fork from another bike that will fit? I've read a bit about the Suzuki WB. What are the issues with that set up? Any other forks?

Are there disk capable sliders from other bikes that will fit?

Is there a need for fork reinforcement?

What questions am I not asking that I need to ask and will only discover halfway through the project?

Thank you.
The double disc set up has been done to the stock forks (does require one new fork leg for the 2nd caliper) I beleive Norvil sells the kit. My own opinion is that the double disc is probably overkill on a bike with the weight and speed capability of a Commando, but hey they look good. Probably won't help the already deficient front wheel much either (see NORBSA's comments on an earlier thread).

As for changing the entire front assembly; it's like my machinist friend tells me "you can do anything you want as long as you've got the time and the money". Any chance of a drop in replacement is slim, but one that uses the donor bikes triple trees would probably be the easiest, especially if your not trying to match the rake and trail on the Commando front end. You may end up with a bike that handles like dog poop when your done so be carefull, and good luck.


I agree with Scooter about potential handling problems when switching front ends; be careful here. Also, in my mind, making major changes to a vintage British bike destroys some of the charm of owning it in the first place. Perhaps a more modern motorcycle with a twin disk front end would be the answer to your braking problems?

I appologize for sounding maternal.

dual disc

I agree with you Jason regarding too many modifications to a Commando. Somewhere there is a line after which it doesn't make sense to put money into the older machine. It would be better to buy something that already has the attributes desired. Next year the Norton 952 should come down in price.
I have seen a GT 750 (WB) conversion on a 72 Interstate. It looked very clean. I talked with him and IIRC, he didn't modify the frame neck, just the stem, he shortened it. I don't know about bearings and so.
The whole thing cost him about $500.00.
I want to thank everyone for their replies. It is all good advice.

I am an inveterate tinkerer. Every thing I own has been modified to function in the way that allows me to have the thing work the way I want it to work. I love the process of learning and them making the parts etc.

The Norton is a great classic bike. And, I want to see if I can make it respond in the way I want it to run and stop and handle. That's the fun for me.

I get no real pleasure from buying the latest and greatest. My car is a 1980 Porsche that is faster and handles better than the latest from the factory. It's all carbon fiber, with significant engine and suspension mods. I want to do the same with the Norton.

But, I want all the advice I can get. I am happy to learn from other's wisdom and mistakes.

Best to all,

I can understand your affection for tinkering and improving a vehicle, I must admit I do the same thing. I've also got an "82 911SC so I know what your into with yours.
Again like Jason I hope I'm not giving you advice that sounds "maternal" but realistically the Commandos no matter how wonderfull they are have some built in limitations. At the risk of getting everyone out there PO'd I'm going to say there is nothing you can do to a Commando that will get it even close to the performance of the current crop of Japanese sport bikes. I've got a '94 CBR 600 Honda that will make any Norton out there look like it's running backwards. That said I still love my commando and I can guarantee you I'll have it when the Honda is long gone. The reason these old bikes have such an appeal isn't because of their performance or lack there of its' because of their character and the joy they bring to us as we work on them and tinker with them and for us old dogs they take us back to our squandered youth and happier times. So like NORBSA and others in this group I truly believe that taking the stock bike and subtley tweeking it in a few areas while essentially retaining the stock look is the way to go. I think illf8ed said it best and when you make too many changes to the stock bike it no longer is really a Commando and it doesn't make sense to throw a ton of money into it when the end result will still have limitations.

Scooter aka Old Dog
I went the whole hog and installed the stiffening kit to the drum brake on my 72 and did the RGM 13mm resleave kit with a ss teflon line and a ground down and drilled rotor and ss pistons in the caliper dot 5 fluid on my 74. They ar both two finger brakes and all these mods are cheap if done right.

The stiffining kit is from Norvil it works real well it's a longer set of pins and a backing plate stops the shifting under hard braking. Mine is now a two finger brake. here's a picture of the backing plate installed. You will need to make a service toll to set the rivited system you will see what I mean when you get it real simple vice held tool. See picture at norbsa[/url]
I'll be gone for a week and will check back in when I come back.

After listening to y'all I'm leaning toward modifying the front drum. Backing plate mod, perhaps 4 leading shoe mod and the best compound I can get, as well as the sleeving and teflon lines, or 1 disk tricked out.

Engine: I want to try fuel injection with integrated electrics, as I've put on my 914 race car. It's not too expensive for 2 cylinders and affords maximum air flow and velocity as needed across the full range. 1 piece lightened crank with superblend bearings, Carillo rods, lightened rockers, titanium pushrods, lightened lifters, titanium retainers, appropriate springs, 9.5 CR, balanced, flow heads and cam developed on flow and exhaust characteristics.

Transmission: 5 speed Quaife.

Suspension: Fork mods and progressive springs, with rear Koni's and appropriate springs. Later isomers with vernier adjusters. Suspension really still up in the air. Alloy rims. I need expert advice.

Looks: Polish, stainless and black chrome. Paint still up in the air, but BRG, or yellow are options.

This will keep it vintage looking with mods to make me feel good. I'm looking for crispness at turn in, predictability in the drift through fast corners, crisp throttle response, with power band from 4K-8K, and brakes that will stop it.

Any comments appreciated, especially from people with experience with proposed mods.

Project to commence at the end of the summer riding season.

Again thank you for the time you've taken to help.


Pretty impressive list. Is this for the street or the track? I'm interested in your injection plans. I've wondered just how tuff it would be.

About the Quaife, you should realize that the gears are about 1/3 narrower in a box originally designed for about 30 HP. (read..FRAGILE) Also the ratios are closer throughout with a higher low gear than stock and still 1:1 in 5th. Great for the track, a pain for the street. I sold mine before I even hooked it up behind my hot-rod 850.

Engine mods sound good, but 1-piece crank and Carillos would not be necessary for the street except for bragging rights. Good track mods tho.

Keep us up to date with some in progress details and pics!

Ron L
Quaiffe Gearbox

I have been running a 5 speed Quaiffe for about 15,000 miles. I also have the stronger gearbox shell (Its particularly stronger around the bearings). I have the reverse camplate too. 21 th countershaft.

I ride the bike really hard everywhere, except in towns. The gearbox comes into play when riding through the tight mountain roads. The gearbox comes into its own there. It transformed the bike!

1st gear is a little high with the Quaiffe, so I generally take off with ease, and start powering while in second.

For what its worth I love my gearbox. Having said that, I am thinking about putting my Commando back to stock someday, and will probably put the 4 speed back in when I do.

Hopefully my gearbox will be OK.
Back from 8 days kayaking and camping in the Rogue River Wilderness.

Thanks all for the input. I'm riding the bike this summer and will begin the re-build this winter. I'll have b4 and after pictures, including step by step with the Fuel Injection. I did it on my 914 race car. It's not difficult and about 2x the money for the Boyer & single Mikuni set up.

The bike will be a street bike that I can take to the track, so it will be a compromise in both places. I live 45 minutes from Sears Point (Infenion) raceway and 2.5 hours from Thunderhill. It's a toy, not transportation, so I'm willing to put up with some inconvenience.

Best to all for a great summer.

Just a couple more thoughts on setting up the drum brake. There's been some discussion on INOA about this. People have mixed opinions on the stiffening kit. Some say it made a big diff, others say they noticed little improvement. Two things most people seem to agree on are new shoes with Ferodo linings and a brake cable w/o the inline switch Eliminating the switch is supposed to help a lot with the spongy mushy feel.

It's going be awhile until I get my disk front end built up so I have to make do with the drum for now. I'm going to try the new shoes and switchless cable and see how that works. I'll post again with the results when the parts come in...

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