Whilst deciding on what sealant to use on my 71, I thought I would reset the tappets as I have just re-torqued the head after fitting a new copper gasket. Having set the inlet valves to the required 6 thou I wound the crank round to set the exhaust valves and heard a very distinctive metallic click. On closer inspection it appears that both inlet valves when just starting to close do a little jump that appears to be the origin of the noise. Seems like some sort of spring binding maybe. As the bike sat in a shed for 20 years I'm not sure what the bottom end build was. It has new 60 thou oversize pistons, so maybe the bottom end had been modified. I suppose I better measure the lift on the valves, it may have a non standard cam.
Anyone else seen this problem?
On rotating the engine in…
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Pushrods not fully engaged…
Pushrods not fully engaged?,pushrods catching on new head gasket? valve guides going up and down with valves(mine did!!),tight valve stems in guides?. carboned up stems? cam followers sticking,(in the wrong way).
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Almost certainly one or mo…
Almost certainly one or more pushrods not located properly in the rocker. This is quite a familiar event when replacing a cylinder head... Gordon.
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I can confirm Gordon's co…
I can confirm Gordon's comment. It's even more likely to happen when you have either a head that has been skimmed down or a higher lift camshaft. The dreaded metallic click - been there, done it. The only solution is to wind down the head bolts very slowly and progressively, checking things are OK at every stage.
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Thanks for info guys, I wa…
Thanks for info guys, I was pretty careful reassembling the push rods, chocked the head up and made sure they were seated in the guides and then the rockers. Interesting comment on catching the new head gasket Robert, I had to drill out the two holes for the forward two smaller studs, they were about 1mm undersize. If the pushrods are fairly tight through the barrel to head region then maybe they are catching a badly machined gasket. Either way sounds like the head has to come off again, I have a few suggestions to work on now thanks, and nice to know that it is a fairly common issue.
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Thanks for help guys, Robe…
Thanks for help guys, Robert got it. New head gasket a very poor fit. At least 1.5mm overlap on the front edge of the push rod tunnels.
Problem solved, cheers peeps.
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On rotating the engine in the correct direction, anticlockwise on drive side, (doh!) the click and sticking has moved to the left hand exhaust valve only. Very odd?????