Hi Guys
As usual great advise from you all.
Yeah noisy tappet was my first thought and I did the tappets again, but no difference.
Muskrat – Interesting you had the same problem with the belt drive, I thought I had the tension about right, I’ll try a bit tighter but I don’t want to overload the idler bearing. If the noise persists I’ll get the Dremel out and do a bit of grinding as per your solution.
Mitch – Would never have thought of the primary case screws as the problem, you did well to solve that one. Easy to check so I’ll have a look.
My gut feeling is it is something to do with the backlash in gears, sticky lifter and valves sequence, this engine has had less than an hour of running since I put it back together, so things might improve on running in.
The back story is that the engine was seized when I got it, due to part failure of the oil flow (a story for another time) so the piston was seized in the cylinder which is probably just as well, because on removal, both small end and big end bearings looked like they were going to fail in a big way, if the piston and barrel had not decided it's too hot and called a halt to things.
I replaced big end and small end bearings new pistons for a newly +60 rebored and unused barrel I by chance found locally. I gently reground the valves onto their seats but reused them the guides and followers. The followers were transferred over from the old barrel and I was concerned they might be a bit sticky, especially given those awful aluminium pushrods which I thought at first might be some homemade bodge until I checked.
I probably should have renewed all the valve gear, given how much other work I’ve done on the bike, but I can easily do this at a later stage and I just wanted to get the bike up and running.
Cheers
Degsy