Honda-SOHC

On mine there are screws not bolts holding the cover on.  Sometimes people put a bolt in if the screw is lost/broken.  However, if one does, it needs a washer so that it protrudes enough to get a socket on.

If oil is getting up to the top I am sure it is fine, and if the timing is right, I would investigate the dirty petrol theory.  I have in-line filters on mine.  They are really cheap to buy and keep all the grime from my tank away from the carbs.  Before I installed filters I was stripping the carbs all the time which is a really boring job and they are a pain to get on and off.  

Is your bike a 550 or a 500?

Very nice job Steve, I have thought about that or my preferred and latest idea is to get two down-pipes for each side and make up a 4/2 system.

Spitfire, those were the original pipes, these are Motad pipes which I suspect do not have such a good layer of chrome and we do get a lot of mud around here which I am far to lazy to kick off.   Even so, they have lasted for ten years so I do see what you mean.

Matthewmosse, good idea, I could weld some pipe onto the good bits of the down-tube.  I am getting ideas of some dreadful Frankenstein pipework which will look awful but be functional and I'm liking it already.  I did see a picture of a brilliant cb550 which had a home-made exhaust and I was very impressed, although I suspect it was too loud to be of use really.

Please can anyone tell me, will CB650 exhaust down-pipes fit onto a CB500 four?  My exhaust is falling apart, the MOT is due fairly soon and I need to find a very cheap way of repairing it.(the gun-gum only lasts for so long! and the holes are getting bigger)  

I have noticed there are some CB650 down-pipes on ebay but I don't want to buy them if they can't fit.

The down-pipes on these bikes are a real mud-trap, the bikes on it's third set now.  I think I should put a rubber flap at the bottom of the front mudguard.

I have worked on these for years and they are really difficult to get right when you tighten the lock nuts.  Make sure the threads are completely clean and lubricated and make sure that the washers are not too chewed up.  Make sure also that the screwdriver you use fits the slot really well and has a handle which you cam grip very well.  It helps to get them close with the locknut only just loose enought to allow movement and then when you do tighten them up don't over-tighten.  It is extremely fiddly but with patience you will get there.  Also make sure you have the marking lines pointing the right way according to the manual.

Thanks for your contributions, to conclude it seems we think static timing is a good method.

For some reason I cannot ever get the timing correct with the recommended points gap of 14 thou because the points never close at that setting.  I have to set the gap really small to allow them to close as the points cam doesn't seem to have much lift.  Is this normal?  Also with a larger gap there isn't enough adjustment in the second set (i.e 2,3 ) to allow them to be timed.  Is it possible that my points cam is worn out or maybe that the pattern points are not quite to the same spec as the original fittings?  I've never known points cams to wear out before but then I suppose anything is possible.  Your thoughts and experience would be very much appreciated as I have never come accross this on any other vehicle before and I do work on a lot of engines.

I used to be a member but I am now a member of the Vintage Motorcyle Club and I find it suits me better.  Although the majority of the members bikes are British there is a growing interest in Japanese bikes and I have not encountered any snobbery.  It also means I get very cheap insurance.