Took my leaking head off my 1941, G3 this last weekend, There were no valve stem caps fitted, I have been riding the bike eight years and never taken head off, question Is should there be valve stem caps fitted, Should have read about BSA C 15, head gaskets before I did this job,,Thats much better than the silly ring thing, Any answers folks, Andrew.H.
Hi, they should have the caps to allow the optimal angle for the valve operation, if not fitted the rocker arms could just catch the valve spring cap or the rocker arm also runs the risk of digging in the top of the stem as it arcs it may come off the end of the curve on the end of the rocker shaft causing premature valve/rocker arm wear
The hardened valve caps were only used on pre and wartime engines, as the valve stems themselves were not hardened, and started mushrooming, when not using the caps.
If you have later valves fitted, they have hardened valve stems,and are a little longer too, to compensate for not needing the caps!
So check what valves you have first, before doing a repair that might not be needed!!
Thanks Lex These valves are in very good condition the inlet has polished up well, There is no mushrooming on the ends after a couple of thousand miles, I recon the later valves have been fitted, will have a check against a pair of new valves I have somewhere, Andrew.h.
The valves in the existing head are shorter than my new ones, have found two valve stem caps so going to fit them tonight.dont think it will do any harm , then its for a start up, Going to sort out a bike for normandy Sunday, somthing with paniers ,a BSA M20 I think Andrew.h.
