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[MadMike]

OK so the wheel and drum/sprocket arrangement is the same as a Norton. However even if the drum is not laced to the rim, you must still get the brake plate with shoes fitted turned to match the brake drum. Skimming the drum makes it larger and so standard linings on shoes will probably not make up the difference or will simply consume all of the adjustment. If you are using the original shoes/linings then they will have worn to suit the drum which you have now skimmed and made it round again. Did you in fact have the shoes skimmed to match the drum? If you have then simply centre the plate as described earlier. Remember to slacken the brake torque arm or any bolts designed to stop the plate rotating in use before you centralise and re-tighten afterwards. HTH.

[tribonnie]

Westyboy a bit of clarification for you (hopefully).

As you say the alloy brake plate (introduced by enfied because the steel on distorts very easily) has no brake shoe centralisation. The non brake cam end of the shoes are machined with a round "groove" to locate on a round pin which is cast into the brake plate. The is no way the shoes will move if things are left loose and the brake sharply applied.

When brake drums are skimmed it is essential that the machinist makes either, a mandrell that picks up on the central bearing surface, or they are mounted in a four jaw chuck and centralises onto the brake drum surface. Mounting with a three jaw chuck on the outside casting will almost certainly result in a brake drum suface that will not run true to the wheel spindle. As suggest above, when the drum is skimmed the shoes must be skimmed to match.

The symptoms you have suggest the brake drum skimming is off centre. A way to check this is by riding the bike, gentle apply the back brake and if you feel the brake lever moving up and down as you brake the the drum is off centre to the brake shoes. Or, run the bike on the centre stand and apply brake with your hand (a two person job, one silling on the bike whilst you apply the brake).

If a lot of movement in the pedal then the best thing is to get the drum/shoes machined again.

Richard

[MadMike]

If what Tribonnie says is correct then he is right in part. The "centralising" I have described will not move the shoes on the brake plate.....but it is not meant to. What it will do is to centralise the plate itself in relation to the brake drum. However his point about the method of turning is absolutely correct when he says that the hub must be centralised by using a mandrel fitted into the centre wheel spindle hole and any bearings that may be fitted. The use of a 3 jay chuck will only give a rough central position but it will be based upon the outside of the drum which in turn may not/is probably not concentric with the outside of the cast drum. The use of an independent 4 jaw chuck is an improvement but will not necessarily solve the problem. It will rely on the drum being concentric with the centre hole again, and if that was the case you probably wouldn't have the problem. An accurate mandrel is the only real way to get the right sized drum with concentric diameters in the centre and in the braking surface. Did you have the linings skimmed at the same time as the drum? If so do you know how they held the drum and the brake palte?