Noisy top end....Camshaft?...

[AndyDenmark]

Hi all.

I have a Golden Flash with a frame that appears to be from 57 and what appears to be an earlier engine by what I can work out. The engine number is CA10 1773. I am not yet at the stage where I can do strip downs etc so the bike has been into a workshop for a check over and the mechanic commented on the fact that the top end was quite noisy compared to others he has worked on. He reset the gaps and said they were much larger than they should have been but it is still quite rattly and he seems to think it may be the Cam shaft. I have no reason to doubt his judgement but have a couple of questions.

1) Could it be something other than the camshaft causing a noisy top end when the gaps are set correctly?.

2) If upon him getting in there and the camshaft has to be changed how do I know which camshaft to order as I have read in here there are different ones and I am possibly going to order the parts from the U.K to make it cheaper as I am based in Copenhagen .

3) If it comes to replacing the camshaft which other parts are standard or good practice to change at the same time?, just to give me an idea of costs.

I realise some of my questions may have several answers but any guidance would be apreciated.

Many Thanks

Andy

[Topdad]

Hi andy , never had this problem but sure it's happened before . You've got a small journal motor fitted up to I think '56, but design the same for all. When I rebuilt mine and fitted a new cam I was advised to fit new followers as well which I did. I'd also have a look at the pushrods to make sure they haven't worn due to gaps . There must be a few things to check first how about dynamo chain and is there any obvious end float on the cam. Someone else will come up with some more ideas. Should you need a cam well you need to decide on your mode of riding ,ie sporty or slower and then use someone like SRM ,talk to them they are good and take it from there best wishes BobH

[bikerbob]

You need to try and locate where the noise is coming from  I have a mechanics stethascope which is handy for locating problems but you can improvise by using a long screwdriver put the handle to your ear and the metal end on various parts of the engine try the rocker box if the noise is coming from there it could be worn valve guides if it is coming from the base of the cylinders in the camshaft area it could be camshaft or cam followers. The correct part number for the camshaft is 67-334 the correct part numbers for the cam followers are inlet  67-332 and exhaust 67-333. Now you can get the camshaft and followers repaired by having them welded using stellite rods then reground to the correct profiles I had this done on a Gold Flash many years ago and they were still perfectly OK when I sold the bike 17 years later, at the time it was much cheaper than buying new parts.

[AndyDenmark]

Thanks for that guys. I will get the screwdriver out tomorrow and try and locate exactly where the rattle is coming from. It is definitely a regular mechanical noise rather just something randomly rattlling if that makes sense?. If it turns out to be the camshaft I will replace the followers as suggested and look into having the worn one welded and reground.

Thanks

Andy

[muskrat]

G'day Andy. Does the rattle start from cold or does it start once warm and get a little worse as it heats up? That would indicate guides or rocker end float if the springs are replaced by shims. Could also be little end bush or piston slap.
If the cam/followers are to be replaced a full rebuild (cam bushes, big ends, mains, sludge trap, oil retaining ball & spring) is what I'd do. Motor out, cases split is a job you only want to do once so do everything that wears/needs doing.
Cheers

[AndyDenmark]

Hi Muskrat and guys.

I have been over her with the screwdriver/stethoscope and it is hard to localise the noise but I am starting to think that a large part of it seems to be coming from tbe Dynamo area and a lesser part from the rocker box. It does it from cold and I think it gets a bit worse when she heats up but I am not 100% sure as you know once your imagination gets going you start to imagine all sorts. It does seem to be more towards the front face of the cylinder heads rather than the rear. I hope this makes sense.

All the Best

Andy

[Beezageezauk]

Hi Andy, 

Ive just had a thought.  The BSA Owners Club has a massive membership in Denmark and I'd be surprised if they didn't have A7/A10 owner/members in Copenhagen who could listen to your engine and give you advice.

I would suspect a worn camshaft and/or cam followers but the only true way to tell for definite is by actual inspection.  The minimum amount of work to check this out would be to lift the barrel.  The cam followers can be clearly seen on the underside of the barrel and with the barrel removed you will be able to see the camshaft down inside the crank cases sufficiently to determine if it is worn.

Beezageezauk.



 

[muskrat]

 I totally agree with Beezageezauk. A couple of quick checks. Timing cover off to check dynamo chain. Tappet inspection covers off and with each valve in the fully closed position, try to push/pull the keeper back and forth. This checks guides and broken springs.
Cheers

[AndyDenmark]

Thanks for the help guys. She is going into the workshop on Tuesday and left there for a month while I go back to sea and earn the cash to pay for it :). I will let you know the outcome :).

Andy