I find that the fitting of Belleville spring washers between the carb. flange and the holding nuts helps to reduce the distortion of the flange. The washers allow the whole of the carb. to thermally expand and contract rather than just the central part when the holding nuts are tightened. They are p...

I had a similar problem with a cylinder head oil leak on my KH500 some years ago, after checking all possible causes I finally came to the conclusion that I was not able to apply sufficient torque to the nuts with an open ended spanner. I therefore trimmed a small amount of material from the cylinde...

Amendment to my previous attachment.

John P.

I had a similar problem on my KH500 some years ago, solved it by fitting an extension piece, see attached.

Joihn P.

I had a similar problem, I found that one oil leak was due to the "split circlip" that holds the drive connector to the gear box drive, the oil leaks via the split in the circlip, I fixed the problem by making and fitting a non split circlip that had full sealing faces. The other leak was ...

Rob sorry to hear of your problem, let it be a warning to us all. Just a suggestion, would it be better to bolt the two half casings together, even maybe with the crank shaft in situ, prior to welding, this would hold the casing much more rigidly to avoid any thermal distortion when welding. John P.

I initially fitted the magnetic pickups to try and clean the oil before it enters the engine rather than when it leaves as per the cartridge filter, whether what I did is necessary I would say it is not. These engine had been running quite well for some years just with a wire mesh filter ie prior to...

Paul, I do also have a cartridge type filter fitted,the magnetic particles picked up by the magnets may be too small for the cartridge filter, this depends on the grade of filtration within the cartridge, see attached sketch of the setup.

John P.

Have recently cleaned the 3 magnetic particle pickups that are fitted within the oil flow system on my KH 500. 2 are fitted to pickup magnetic particles as the oil flows into the oil tank and the other to pickup magnetic particles just before the oil enters the engine. They really do pickup some mag...

This is a method that I use for fitting the Amal carburettor to avoid thermal distortion to the fitting flange; it allows the whole of the flange to thermally expand/contract rather than just the central area when normal nuts/washers are fitted and fully tightened, see attached. Belleville spring co...