Forum

[Pike]

Hi, I realised that the inner side of the primary chaincase touches the clutch spring cover, I found a half-circle groove grazed in the chaincase and aluminium powder in the chaincase oil. The clutch bolts are tight, no way to move the spring cover further inside. Did somebody have similar problem, what to do? Thanks.

[Mark M]

Pike, 4 possibilities spring to mind. 1) The original clutch screws have a low profile head, if replaced they may be too thick. 2) Is the primary chain in line with the clutch drum? The answer to this would help eliminate some possibilities! 3) The gearbox mainshaft should have no discernible end float on it, check this! Finally, have you replaced the friction plates recently? The modern ones are good but a bit thicker than the originals.
REgards, Mark

[Norm]

Not a lot of clearance in there and check everything as Mark says. Most outer covers show signs of the clutch hitting it at some stage

[Pike]

Thank you for the hints. New thicker clutch plates could be the cause as I bought the bike a few miles after a home-mode overhauling, there are small issues to sort everywhere. I will check the other points too. However, the later chaincases do have a calotte for the clutch. I would grind about one milimeter from the chaincase (in the rear part where the half-circle groove occured) to make a sure clearance, is it a wrong idea?

[Mark M]

Pike, it shouldn't be necessary to grind the case if everything else is correct. The metal is quite thin in this area so I would not remove any more! By the way, I do not know the word "calotte", (I assume English is not your first language,) we would say "recess" which is a more engineering term or just possibly use the word "scallop" to describe the shape as looking like a sea shell! Good luck, REgards, Mark

[Pike]

OK Mark. Yes, recess is more correct I am from the homeland of the Jawa motorcycles.

[Mark M]

Welcome, by coincidence I heard yesterday that a friend is thinking of buying an old Jawa and wants to borrow my bike trailer to fetch it! I have a 1953 700cc Meteor which is very similar to your bike so I have had some experience with them although I have never ridden a 500 Twin. It should be very nice indeed by all accounts!
REgards, Mark

[Pike]

Oh yes, was it your bike featured on the realclassic page. I also ride a 1958 Jawa 350 as a tourer machine on holidays. Don´t hesitate to contact me if your friend would need some spare parts, I have a good source near here. I would like to own the Meteor beside my Twin in the future too, we probably should meet and borrow the bikes to each other for experiences

[Mark M]

Yes, that is mine, and me with it! Thanks for the offer, I'll mention the Jawa parts to Mike when I see him. Also yes, I'd love to do a comparison test, that would be most interesting!
REgards, Mark