Rocker box stud

Thanks Baz. I'm hoping not to have to send it off.But I'll wait for more views. G

BTW Baz, I forgot to ask - do you know the TPI of the stud at the cylinder head end? George

Hi Baz - after a bit of research I find that the stud should be a 5/16" with a TPI of 26. Now I've got to find if Time Sert or Helicoil do that size. Thanks for your help - George

Now I'm getting confused Baz! Which chart are you referring to? I believe the threads are different at each end of the stud but I'm on about the end that screws into the alloy cylinder head. George

Doh! Just realised you're talking about the chart you attached earlier on. My apols. But that's Whitworth and I think the cylinder head thread is 5/16"BSC at - I thought - 26TPI? george

Oh well. Back to square one! I'll keep digging. I need to get it right so's I get the correct helicoil or insert. George

Don't know what that is, Dan. Mine has an alloy head. Is that a "Wellworthy"? Does this affect the thread - or rater, the TPI. George

Sorted! After an interesting and informative telephone chat with Ian I now know that the stud is a 5/16" with a Whitworth (coarse) thread into the head and a fine (26TPI) BSC thread for the nut. Now I can set about sourcing a Helicoil or insert set for the damaged thread in the head. Many thanks for all your help, Ian. George

Thanks Dan. Life is one great learning cycle! I'll check what's written on mine tomorrow. It certainly has an iron inner. I realise about the front and rear studs. the one last confusion is that then rocker box is held on with studs on my bike but RGM tell me it's a bolt. They don't do a stud. I'm trying to glean from them what the thread is so's I don't buy the wrong helicoil. And so it goes on........... George

Once again Ian, that makes a lot of sense. problem is that at present I'm getting two different answers and both seem feasible. I may have to go down the bolt route as it seems the only thing available. Once RGM confirm the thread type/ size I can move. Thanks again. George

So grateful for all your inputs guys. Information overload! I've taken the plunge and ordered a 5/16 BSF bolt plus a helicoil kit from RGM. Total cost about £40. Expensive for what is effectively a stud replacement but there you go. Onwards and upwards! George

Just checked, Dan, and it is indeed a Wellworthy iron skull head. Also thanks for the tip. I've put a hold on my order as another query has arisen over the efficacy of changing what may well be a Whitworth thread in the head to a BSF. All good fun!!George

Very drole, Baz. Your obviously a man of infinite wit! George

Very drole, Baz. Your obviously a man of infinite wit! George

Just to tidy this up - I emailed Mike Pemberton and apparently it is quite OK to fit a 5/16 BSF helicoil in place of a 5/16 BSW socket thread. So a new 5/16 BSF bolt will do the job. Sorted - I think........George

Thanks Baz. Now why couldn't I find that! I may well get a stud and keep the bolt as a spare. Cheers, George