Front disc query

I think only Mk3's had the disc on the left with the introduction of the rear RHS disc, possibly to balance the lateral braking forces and prevent the bikes from veering to one side under braking, although mis-alignment in several areas could cause this.

If you suspect a bent frame ask the owner, or check wheel alignment with a straight edge eg string. Although this will not guarantee a true frame it will give you some idea tothe level of maintenace of the current owner and a possible insight to it's roadworthiness/usability,

Simon.

Previously wrote:

Hello, I would be grateful for any advice regarding a bike I am thinking of buying. It's a 1973 750 Commando with matching numbers, and looks pretty sound. The only thing that doesn't look correct is that its front disc brake is on the left side, but according to the Norvil website, Commandos up until '75 had right side front discs.

My question is, were any pre-75 bikes built with left hand discs for any reason, or is there any good reason why an owner would fit a left hand disc. My concern is that if it has had a later front end fitted, it could well have been involved in a hefty crash.

Many thanks, Patrick.

I understand that pre Mk 3 bikes did not leave the factory with the disk on the left. However, from what I've read some owners chose to switch the disk to that position because it appeared to neutralise a pull to one side. There are some commando service notes which refer to this. My Mk11A has the diskon the left butI intend to put it back to the right as I want it to be stock.

Hope that helps.

If you want to see if the bike has a whole Mk III front end, look at the wheel bearings in the front wheel. Pre Mk III Commandos had a screw in bearing retainer, like just about every other Norton back to pre-war days. The Mk III had a circlip to retain the bearings.

If the bike had been involved in a "Hefty" crash, the frame top tube would be bent if the forks had been bent seriously enough to require complete replacement. If that was the case, any repairs would be visible or else the frame has been replaced. Don't ask how I know about frames bending when forks are damaged...

Just one more point, Patrick. The bearing retainer, mentioned earlier, can have a slight tendency to unscrew when the wheel is turned the other way in the forks. The rotation of the wheel is now in the same direction as unscrewing the retainer ring.

Perhaps the retainer should be removed, cleaned and refitted with loctite on the threads?

Maybe other members have some experience of doing this, and can comment further....

Allan.

Just one more point, Patrick. The bearing retainer, mentioned earlier, can have a slight tendency to unscrew when the wheel is turned the other way in the forks. The rotation of the wheel is now in the same direction as unscrewing the retainer ring.

Perhaps the retainer should be removed, cleaned and refitted with loctite on the threads?

Maybe other members have some experience of doing this, and can comment further....

Allan.