RGM master cylinder sleeve down kit!

Hi Rob,

I have recently done this conversion to both my Commandos and it improved both brakes.

I know mine were not spot on, but don't remember they were 7.5mm out. The position of the holes in the new sleeve are designed to line up with the new piston, which is more important than lining up with the original master cylinder holes. As RGM said the fluid does flow around the space, one reason why you bore out the master cylinder. You will also notice there are four holes in the new sleeve. I don't see it would matter if the master cylinder holes were enlarged? But I don't know if anyone has done this. Be assured it does work with holes out of line and it should improve the front brake when using the original Norton Commando caliper.

Regards, Alan

I think I might baulk at the logic of this too â but if you can install the system, fill it with fluid and bleed it successfully, and then the brake works, for example while just pushing the bike around, that'll probably tell you all that you need to know? So long as there's a head of fluid remaining in the reservoir, and so long as the seal on the master cylinder pistondoes seal, pushing the fluid to activate the pistons in the caliper, and then retracts, that's all we want. Many years ago I sent my master cylinder off to RGM for sleeving, so I never saw the inside of the kit, and around the same time I fitted an AP Racing caliper. The best I could do was to put it all together, try it and see. The system's still working great for me. HTH

A fellow Shropshire Branch member was fitting a replacement RGM sleeve in his master cylinder, I had to turn down the end of the sleeve to get the groove to line up with the holes in the master cylinder I recall.

I'm afraid RGM have form. Many years ago I bought one of their fork braces for my 850 Commando. It came with an extra pair of bushes and the lateral adjustment to make sure the fork legs were the right distance apart was via selecting paper(!) washers under a securing collar.

The bushes would not go over the (new from Andover Norton) fork stanchions. When I measured them with a micrometer the stanchions were spot on; the bushes were .003" (IIRC) undersize. And it was impossible to adjust the fork spacing with the mickey mouse adjustment arrangement.

When I pointed these things out to RGM they said it was my fault and that their items were designed to be fitted by a "competent person" Hah!

Another poorly made part was an adaptor plate for a racing Lockheed caliper. Described as being "CNC machined" it had a crack in it. Despairing at this point I made my own out of alloy plate.

I'm sure many of their parts are fine but I'm not at all impressed by the stories above regarding what is a safety-critical component.

Uh-oh, maybe I spoke too soon ... But if fluid flows ...?

A fellow Shropshire Branch member was fitting a replacement RGM sleeve in his master cylinder, I had to turn down the end of the sleeve to get the groove to line up with the holes in the master cylinder I recall.