Horrendous valve clatter and lack of go

[paul.jameson]

Knowing that you made up your pushrods, I wonder if the ends have moved further onto the rods with running. That can be difficult to detect on the exhaust valve particularly, if the valve lifter is preventing the rocker from coming fully up. You end up with what feels like a small gap on the valve stem when in reality there is a large gap between pushrod and rocker.

[john.nash]

Thanks for the info everyone !
I've got it apart and....... can find nothing untoward .

I'll swap in my single lobe cam and reset it all up and go from there. i'll need some bits from Drags tho (and the post are on strike now ... )

Paul: I tried all the easy stuff with a variety of clearances, lifter off etc etc. None of it made the slightest difference to clatter or performance.

[JohnnyBeckett]

hi john it maybe the lobe on the cam and the post is not on strike now ] sorry i spoke to soon the post is going on strike again

[Brian_Walker]

Make sure with 0 clearance that your tappet adjusters are set in the middle of their travel that means the rocker arm should be roughly horizontal if the pushrods are the correct length. Next adjust the clearances "not with a feeler gauge". Ie the thread is 26 TPI so one complete rotation is 1"/26 = 0.036" you can work it out from here what you need to do o get the right value. Mine is about 0.005 on exhaust which means I turn the tappet adjuster which has a square head about 1/8 turn.
Another point :
As I have high lift cams (twin lobe) I needed to adjust the tappets down till the compression let go on each one in turn then I turned them back a wisker to where I thought they were just starting to activate the valve that's my zero clearance.. (There is quite a lot of preload on the valve train before it takes up) Doing this I now have a quieter engine.
Rocker shaft endfloat:
Hope this helps also in passing the shim washers help keep the rods running central by setting the rockers in the right place not just removing endfloat. I have some on each end of the rocker shaft to keep my rods central (mine is a VCH so probably not as critical as one with acoustic tappet tubes.

[john.nash]

Update.

I swapped in a single lobe cam and followers.
I finally traced fluctuating clearances to the push rods hanging up in the followers and, to a lesser extent, the rockers. ... very odd but cured with some lapping.

Bike is now making what I consider to be typical ariel noises.

Performance is still down, but ill chase carb jetting and z potentially restrictive armours silencer.