February 5, 200719 yr Ok guys , Now ive decided to keep the o'll girls ive set about sorting one out! first problem is the exhaust thread is badly damaged ie stripped! how can i restore this? i dont think you can get a helicoil this big! I think there might be a steel threaded insert for sale on the net! but i assume this is inserted by heating the exhaust port and then pressing it in! but surely when the bikes started up and the exhaust port gets hot wouldn't the insert move about? any ideas on this chaps as the barrell /piston/head are mint! Apart from some idiots handy work tightening the ****** exhaust ring to tight!!!
February 6, 200719 yr Yes inserts are available and they are made of aluminium and are intended to be welded into the barrell. There may be other places to get the inserts but I just bought one for my MAR from Keith Lynas in the US. There is a link to Keiths website on the fantastically informative OSSA site run by Mats Nyberg. They usually strip because the nut works loose and the threads rub together due to engine vibration. Prevention in the form of tie wiring the nut will prevent it happening again.
February 6, 200719 yr Scotty, There are various engineering firms that do this, Norton Commando heads have similar problems. They can also reclaim by welding and re- machining
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.