Knocking noise also but on a model 8

[JohnHewes]

Paul, I would have thought that if you put your hand on the head near the exhaust valve lifter cable end you will feel if it is hitting there.
John

[Ozmadman]

Paul, while the rocker cover is off, have a look and see if anything is touching it on the inside.
Rob C

Doesn't appear to have any evidence showing but if any touching was happening it would be where the rocker arm and lifter touch anyway when operated so it will be hard to tell from any marks there??

Thanks Paul

[Ozmadman]

Paul, I would have thought that if you put your hand on the head near the exhaust valve lifter cable end you will feel if it is hitting there.
John

Thanks, probably would have had I thought of that when it was running but it's partly dismantled now and I don't want to run it with the possibility of more damage until I can discover the cause.

Paul

[John Jarrett]

If you think it is the exhaust valve lifter, I would have thought that you could just remove the lifter (temporarily) and run the bike without it in situ and see if the noise goes away. I have done so before with no ill effects and it depends how long you need/want to run it this way whether you find something to cover the hole to stop oil getting out and anything else getting in.
John

[Ozmadman]

Ok, put the rocker cover back on after calculating where the exhaust rocker arm(push rod end) needs to be in relation to the oil feed hole as the other end (valve end) rocker hits the lifter spindle and worked out that the rocker with the push rod in place will not be able to get into that position with correctly adjusted tappets. There is not a lot of clearance but it's there so this is not my problem.

Progress so far? nothing!!! taken off the head, valves super smooth in the guides everything in place as it should be( I replaced the valves about a 1000 miles ago), clean oil and no bits in it, metal or otherwise. Took off the barrel, piston is excellent(+.40) rings are in place and not broken (it had a re-bore about 1500 miles ago just before I bought it) bore is fine, no ridge. Tried my hardest create some up and down movement in the big end and small end but despite a lot of hard and gentle tugging I couldn't detect even a miniscule amount of play in either, there is side play in both though(the small end is smooth in the rod) There is a bit of side to side between piston and barrel but not much (doesn't burn any oil or smoke.) Next I took of the cam housing, cam wheel is good as are the bearing surfaces and cam lobes, no wear but very slight end float in the cam wheel once the housing is on(should that be shimmed as there is nothing in there). The cam followers have a little wear, the exhaust one having a very shallow groove across its surface and the inlet just a slight flattening, could that be the noise I am hearing, seems a lot of noise for such little wear. Can I "flat" this out with an oil stone?? A gentle bit of leverage under the timing pinion gear confirmed that there is no play in the timing side bush.

What did surprise me though was the amount of carbon build up on the valves and inside the exhaust port especially as it has done less than a 1000 miles since I had the head off and replaced the valves, where it was polished up and shiny. The carbon was black and a bit oily, even though the bike doesn't seem to burn any oil, the piston was light brown on the inlet side yet black on the exhaust side, yet was able to be cleaned just with a cloth and some white spirit and the exhaust front pipe was black and sooty but dry?? It has been standing for about a month so maybe some oil has got down the guides and dampened the soot?? Any suggestions will be appreciated but so far I can't see anything that is wrong(apart from maybe the cam followers)

OH, and I broke the return spring for the valve lifter lever on the head if anyone has one they could let me have/purchase? I also spent about 2 hours looking for a washer that goes under the sleeved head nuts which I thought I had dropped somewhere between the gravel of my front yard and my kitchen, even my neighbour joined in the search!!! Where did i find it ?? still stuck on the head being held in place by my lovely SAE 50 oil.

Thanks Paul