Ariel Owners Motorcycle Club

I bought some reproduction push rods from a well-known UK supplier of Ariel parts and was pleased with the quality. However, when I came to fit them they appeared to be just a bit too long with zero clearance at the tappets (but the valves seated giving compression). I also had a slight clunking sound when rotating the engine. Reluctantly, I dismantled the timing side to see what was going on. The new push rod ball ends were a little too big to seat in the cups effectively making the overall rod length too long. Following Seb's advice I put the followers in a soft jaw vice and lapped the rod ends to the cups with grinding paste. In fact, I had to reduce the ball diameter with a file before using the grinding paste as too much metal needed taking off. I checked the contact with engineer's blue. On reassembly the push rod length is fine and the ball ends move freely in the cam follower cups.
There is a lesson here somewhere!
Dennis

hl dennis that is a good tip to remember to lap the pushrods in i am going to have a look at one of my NH that is noisy at the top end that maybe put together with parts

Given the problem with the push rod ball ends, Seb suggested I should also grind in the push rod end caps to the rocker ball end, or at least check that the rocker ball end fits loosely into the push rod cup. As he pointed out, if the whole pushrod /rocker/valve train is not bedded in at some point wear could cause a sudden loosening of the whole set up with potentially disastrous results. Shame he told me that AFTER I put the rockers back on the engine!
Dennis