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Cylinder thread damaged
Posted: Wed Jul 19, 2017 4:42 am
by njdmoto
Hi All,
I'm working on the restoration of a T250 and I'm looking for a solution to the stripped outside thread on the cylinder. When I don't use an exhaust gasket I can get a little bit of bite on the thread when attaching the exhausts, but that's not a long term solution.
Perhaps I have been searching using the wrong terminology but I can't find anything in the forums.
Any suggestions?
Thanks
Neil
Re: Cylinder thread damaged
Posted: Thu Jul 20, 2017 4:11 am
by rngdng
Man, I don't know. I might take it to a machinist for advice.
Re: Cylinder thread damaged
Posted: Thu Jul 20, 2017 7:02 am
by jabcb
A thread chaser might restore the threads to the point its workable again. A universal tool isn’t too expensive, but I would take the part to a shop that has experience with the tool.
Here is a video:
https://www.youtube.com/watch?v=s9tAVV1EfN4
Re: Cylinder thread damaged
Posted: Fri Jul 21, 2017 1:06 am
by Alan H
Aluminium tape round the threads.
Re: Cylinder thread damaged
Posted: Fri Jul 21, 2017 4:57 pm
by njdmoto
jabcb and Alan good suggestions!
I might try both. Get the thread cleaned up as much a possible, then a bit of tape.
Many thanks
Re: Cylinder thread damaged
Posted: Fri Jul 21, 2017 5:17 pm
by Vintageman
I think its 48x1.5 thread if that fyi helps
Re: Cylinder thread damaged
Posted: Fri Aug 18, 2017 8:36 pm
by willdesign
njdmoto did aluminium tape work?
I've same problem. '71 T350.
Have talked to 2 machinists experienced with bikes & cars and both said it'd be over a day's labour for them: not economical.
Be glad to hear how you got on
Re: Cylinder thread damaged
Posted: Tue Aug 22, 2017 6:32 am
by njdmoto
willdesign,
I have just received the thread chaser, so ill let you know how It all goes.
Re: Cylinder thread damaged
Posted: Tue Aug 22, 2017 2:38 pm
by rngdng
njdmoto wrote:willdesign,
I have just received the thread chaser, so ill let you know how It all goes.
If it doesn't work...fill the threads with JBWeld and rework the threads. I know it sounds crazy, but I did an experiment once where I drilled out an exhaust stud to 1/2" and filled it with JBWeld. After drying for a couple of days I tapped it to 8mm and put a long bolt into the hole. I tightened the bolt (using a torque wrench) and at 20 ft/lbs the bolt broke off. The threads held...
Lane