Crankcase Stud Question

youngjohn

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The crankcase stud at the front of my Comet engine just below the barrel (the one which also holds the tab to attach the top of the mag cowl) has damaged threads where it protrudes from the crankcase, and consequently the nut will not tighten. Looking at the parts diagram, there are 2 types of stud, the early one (ET109/3AS) appears to be a bolt which goes right through from the timing cover, the later one (ET109/13 is a plain stud into a blind hole. To avoid unnecessary dismantling of the timing cover, can anyone tell me if my '51 Comet would have the earlier or later one at engine number 66**? It has a slot in the end so I am guessing it is the later one. I have tried (gently) unscrewing it but it won't move. On confirmation that it's the shorter stud I will weld the nut on it and hopefully it will loosen with a spanner.
Thanks.
 
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mercurycrest

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I think you may be looking at a drawing for a twin. Don't you mean E109/5? If so, it should just unscrew. I'm not positive, but I think all singles had a stud. Why not give it a little smack with a hammer, if it goes inside, it's a bolt and the timing cover would have to come off anyway.
Cheers, John
 

BigEd

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MO65 shows it as a stud. If it is just a slightly damaged thread could you run a 5/16" die-nut down it to tidy the thread?

The crankcase stud at the front of my Comet engine just below the barrel (the one which also holds the tab to attach the top of the mag cowl) has damaged threads where it protrudes from the crankcase, and consequently the nut will not tighten. ..........
Thanks.
 

nkt267

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It's a stud screwed into the timing half. If you can't unscrew it using the screw driver slot that should be on the end if it get the trusty mole grips out, but be prepared if you mess it up then the engine has to come apart..John
 

youngjohn

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but be prepared if you mess it up then the engine has to come apart..John

That's what I thought, and since there seems to be no ill effects coming from this, and the nut (centre popped) is enough to hold the cowling tab securely, I'm tempted to leave well alone.
 

mercurycrest

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If it were my bike I'd beg, borrow or, buy a Stud Remover and do it up proper so as not to have unforseen problems in the future. It's a simple cam action tool that you slip over the stud and using a ratchet, either remove or install studs. It's a tool your entire section can benifit from having available. Vice grips will only cause grief.
Cheers, John
 

Tom Gaynor

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The Stud Remover sounds like a good tool to have. I don't have one. If it were MY bike, I'd screw a nut on the end using Loctite Bearing Fit, or Loctite Stud Lock, or W(ever)TF Loctite have changed the product name to this week, and once it had set, back it out. Then I'd heat the stud very gently - Loctite slackens with not much more than boiling water, and take the nut off. Then review the condition of what you have, and repair or purchase accordingly. Only if that failed would I weld a nut on, back it out, and buy a new stud. On reflection, it must be a stud, because it goes through the mag cowl tab. So it was never AS, assembly, which merely means a stud with a nut BRAZED on the end to make it a bolt, cheaply".
 
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youngjohn

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Updadte - got a stud puller and it came out with a bit of trepidation on my part. Now replaced with a nice replacement stud complete with threads. Phew...
 
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