Hitchcocks Forum

More on the head of my 1951 350cc Bullet. The round tube which the exhaust pipe fixes onto in the cyclinder head is loose, it turns and wobbles a bit but I cannot see any way to get it out to re-fix it securely and gas tight. Any ideas?

Dave

These exhaust stubs were originally cast in to the head during manufacture so I think removing it for repair is probably out. I haven't seen this problem before but could you drill through (from underneath where it won't be seen,) and pin it in place? Given that the exhaust pipe fits over the stub and has a cooling ring clamped on to it there's probably not going to be a lot, if any, movement in use.

REgards, Mark

I suggest leaving it be. my 51 350 was the same but it caused no real issue as long as the header was well secured with a clamp ring. The bike never back fired on the over run and I would liberally coat it with sealant before putting on the header pipe.

Strangely ordinary silicone sealant seems to work amazingly with exhausts, and seems to cope with the heat: could you squeeze and work some in to the area and see if it helps?

That's what I use. I used to buy special red stuff that says its particularly heat resistant but then I discovered its all fine with heat.

It is possible to get a heat resistant caulking fibre from heating supply warehouse, Plumb Centre etc ( used to be asbestos but not anymore ) and caulk it in with a thin bladed screwdriver until it fills the gap, and that will hold it as tight as you like and never move.

Thanks for your help. I can get it sorted now. Dave