Hitchcocks Forum

Hi folks, went for a lovely spin on Tinker this morning, everything tickety-boo. Went to fire her up this evening and after bringing piston over TDC with the decompressor found the kick starter had jammed solid. I pulled in the clutch, which freed it off, so not a gearbox problem. Next I put her in second gear and rocked her forward a bit, which had the desired effect. She now started first kick, but sounded like a jack hammer, the noise coming from the top end. I tentatively engaged first and pulled away. After a couple of yards the noise completely disappeared and she ran perfectly for the rest of the run, about ten miles, during which she was stopped and re-started with no issues. It really was an awful racket, any thoughts as to the cause?

Hi Reg, it might have been the exhaust valve seat coming loose momentarily, as has happened on my 500 once, when I was slogging the engine while on a run with other Enfields. Best to let them rev a bit and not labour too hard. Alternatively, it might have been a tight rocker, or even a valve picking up in a guide. These just came to mind while reading your post, but there could be other reasons than these. Cheers, Paul.

Thanks Paul, I had been keeping the revs well down, though not consciously letting it slog. I'll take your advice and let her have her head a bit more.

It it does it again it was most probably a loose ex valve seat, otherwise a stuck exhaust valve or partially seized rocker.


Check ex rocker and tappet, spin the ex push rod to check it is not bent: spin it and if it oscillates it is bent, and then you will need to look deeper. Check oil flow over the head. If the seat had moved, the valve will be bent from hitting the piston.

The valve MIGHT bend, if the seat moved far enough, but this is not a definite. I realised what was happening to mine and changed down and let her run at higher rpm's and lighter load and made sure it was left at tdc while I went for a cuppa. Half an hour later, she fired up fine and made the journey home without a problem - only 15 miles, but all was well. If a valve seat dropped right out, that could signal a top end rebuild and piston and valve damage.

Thanks Time, I'll check oil flow and pushrod before next run, just to be on the safe side.