Comet Primary Chain Adjuster

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youngjohn

Well Known and Active Forum User
Non-VOC Member
The rear facing primary chain adjusting bolt has stripped its thread on my Comet gearbox. I've had some good suggestions as to how to fix this, but I'm just looking at different options, and in 'Know Thy Beast', it mentions tapping the hole to 3/8 BSF. Has anyone done this repair, and if so, is it necessary to drill the hole first (probably gearbox out) or can the tap be run up the existing stripped hole without drilling? (I recon this could be done in-situ). I could helicoil the thread, but this seems a bit pointless since it appears that the front bolt has already been tapped to 3/8 BSF, and the same question would apply, i.e. would the hole need to be drilled before tapping to insert the 'coil'.
Thanks.
 
Y

youngjohn

Well Known and Active Forum User
Non-VOC Member
Update - Thanks for the PM's guys. Since few people seem to have had this problem, I'll post the answer in case it helps others in the future. I have tapped the hole out to 3/8 BSF. With a taper tap, great care and plenty of lubricant it has cut a very nice thread which, being larger and slightly coarser than the original should be stronger. Back on the road again.
 
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