Hi Everybody.
A Merry Christmas to you all.
My 850 Mk2a Commando has a click when turned over after it has been standing for a few days. I have traced this to the right hand exhaust cam follower. If I pour oil into the right hand rocker cover, it stops the noise. When the engine is running and hot it is not excessively noisy, just a slight tappet noise as usual.
What is the general opinion
a. Do I carry on running as is untill the noise develops into a major noise.
b. Fit new oversize cam followers.
c. Fit new cam and followers and of course all new main bearings which gets very costly
Would appreciate comments on which way to go.
Happy New Year to you all.
Les
Les Mine does this and I'…
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Keith Thanks for info. Thi…
Keith
Thanks for info. Think I'll whip the head and barrells off and have a look.
Les
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Les, May not need to go th…
Les,
May not need to go that far just yet. Back off the exhaust adjusters so you can pivot the rocker (s)out of the way and get a good look at the valve stem tips. Obviously the head needs to come off for valve replacement but I'd look at thetips first before getting into too much disassembly (unless you want to give the top end a 'freshen up' anyway). When you pour the oil into the openings does it flood therocker/valvecontactpoint? That might be a clue. I'm not totally sure what happens (noise wise) with poor valve/rocker geometry but I've always felt that the 'wiping' action of metal on metal could lead to pickup and resulting noise for which I can't find a suitable descriptionright now. Possibly the action of say a dry finger pushed hard on a surface and pushed. Totally unscientific I know but you might understand. Good luck.
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Hi Les, If pouring oil ont…
Hi Les, If pouring oil onto the RH valve gear masks the noise, I doubt that there is anything further down in the engine that needs attention. I would suspect some aspect of the rocker gear. The cam followers wear very slowly and whilst they can be re bored and oversize ones fitted, I haven't heard of anybody doing that. By the time the cam follower tunnels are that far gone you will probably have worn out the piston bores on their maximum rebore.
Whilst they don't wear quickly the cam followers may bind and this could be worth a good look. If something has been dropped down the push rod tunnel it could cause a problem. It is possible to chip a piece of the push rod location cup off the top of the cam follower. If that chip is floating around (or not) it could jam the mechanism up a treat.
Good luck
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Les
Mine does this and I've just re-assembled the barrels and head after a strip to investigate my noisy (ish) top end. It had new followers and cam 4500 miles ago and they are pristine as were the piston pins, piston fit etc. The problem seems to be the click that emanates from the RH exhaust rocker to valve tip which is not nice. I decided to leave it but only noticed the noise when turning the engine over slowly. It needs a new valve but having re-assembled I'm leaving it alone for now. Have a look at your valve tips as it may be the source.