Motorcycle Repair: Leak?, piston head, scooter shops

Question
This is how the nightmare started... I got my first pay check and did what every other 16 year old with a moped would do, spend it on a $100 exhaust to increase my speed by a few mph's. As the old exhaust was being taken off, both studs snappped off, grrr. So we drilled out both the holes and one still had a good thread and was no problem, the other one how ever just comes out after being rid for a minute. So the problem is, the new exhaust is stupidly loud because there is a slight gap where the exhaust goes into the manifold/ piston head, if im right in saying that, well it is only helped by one stud instead of two, are there any quick fixes such as wrapping aluminum foil round it to quieten it a bit? If so how or are there any long term ways this can be fixed? The other stud hole cant be re tapped however because there is no room to get a tap and die set in.   Maybe i could just Weald the exhaust into place and hope i wont have to change it over the next year until i can get a 125 haha :D or do you see other problems with welding?


Thanks Harley

Answer
Harley, You will need to obtain a Heli-Coil or similar insert to repair the stripped threads properly. This will require using a specific sized drill bit to enlarge the hole slightly so a new insert tap can be run down the hole, then the insert installed, which will bring the hole size back to 6mm or whatever it was before.

Find a small square-drive socket that will fit your standard tap and use a 1/4" drive extension and ratchet to drive it in, clear of the obstacles in the way of the tap handle that you are not able to use presently. If the remaining threads are too damaged then you will have to go to oversize thread repair, as mentioned above.

I would imagine that a lot of bike/scooter shops see this all the time and can do the repairs quickly, perhaps at a price that is comparable with having to buy the thread repair kit. Ask around to see who is recommended in your area, if you decide to let a shop fix it.

I hope this is a clear answer for you,

Bill Silver