I ordered the yamaha header gasket for my 465 during the week expecting some form of crush ring but it's just a thin aluminium disc, from memory when I had the pipe off last I worked out that there is quite a gap inside the pipe to the cylinder flange. What do people use?
The other thing I need to know is some dimensions & preferably a photo or 2 of the mount under the tank on a DG pipe, mine has had the vertical part cut off & I think that what I made up isn't right going on how it catches the head when fitting the pipe back on