Suzuki 2 Strokes

Hi guys just found this site and I have a question. I have a 1966 T20, the threads on the left cylinder exhaust where the exhaust nut threads on to hold the header pipe to the engine appear to be somewhat flattened. The exhaust nut threads on very loosely until about the last 3-4 threads then grabs pretty well. I cannot get a tight seal of the header pipe and exhaust gasket to the cylinder. The right cylinder threads are very sharp and seal up well. Any thoughts, ideas, or recommendations to rectify this situation? I thought about having a new exhaust nut made with the threads undercut to grab the exhaust threads better. I have seen on a guys site in the UK who had a guy weld on a new sleeve and cut new threads. Is there anyone in the states that has ever done or could accomplish this procedure? Thanks for reading I am just looking for a solution.

Charles

It's probably been run with that exhaust nut loose, and it's fretted away at the thread.
One solution is to add three strong springs attached to the head and the nut ... tighten the nut up as far as it will go, then stretch and attach the springs to keep it pulled in.

Thanks for the reply. I will keep your spring idea in mind. I found a machinist who is going to make me a new exhaust nut with slightly undercut threads so that I can get a good grip on the slightly flattened threads then catch the good threads for a solid attachment and to be able to put a sealing crush on the exhaust pipe gasket. He says my threads are good enough for it to work so I am keeping my fingers crossed. Still if anyone else has any ideas please let me know.

Charles

That's good. You could consider adding one spring set at an angle against counter-clockwise rotation of the nut, so to unscrew (potentially damaging the thread again) the nut would have to turn against spring tension.

Thanks for the idea. I was also thinking of drilling a small hole in the exhaust nut and safety wiring it to where the exhaust clamp screws into the head. I was thinking of using .81mm copper or .88mm steel wire. Do you think the copper is to lightweight if so what about the steel. My whole desire is to keep the nut from loosening up due to vibration. I think this would be less obvious than a spring or springs. What are your thoughts on the durability of my safety wire idea? Appreciate any thoughts on the matter.

Charles

Hello there; I am new to this forum but I would like to share my experience to help to get you going on this problem. Mine too had the threads worn to the point where the exhaust cap fell off. So I removed the cylinder & drilled & tapped three holes of 5mm diameter into the exhaust stub. I inserted three screws & "loctited" them in place. I then cut off the top portion of the screws & filed them down to the outside diameter of the undamaged thread. I then got a metric thread file (1.5mm pitch) & filed threads into the screws (using the old threads as a guide). I then replaced the cylinder, applied high temp sealant to both the threads & the gasket. Screwed on the exhaust pipe nut & it has held on strong plus hasn't moved after numerous rides. This repair has helped me get going again, I hope it helps you too.
Cheers Bernie from OZ