Here's one method:
http://kawatriple.com/tips/seal_chambers.htm
OR,
scrambler73 wrote:
Mike posted up this trick a while back.. and its one of my favorites! 
Use the blue rubber (made of high temp silicone) gasket that is usually used to seal the headpipe to muffler connection on the stock early H1 and H2 pipes. This gasket hides beneath the chrome connection-clamp and unseen on stock mufflers, but as you can see on the dencos it goes OVER the connection.
I used this trick on both of my bikes with Dencos (one set is from Jim). Its works GREAT as there is a "step" molded into the inner bore of the rubber gasket.
With a bit of high temp RTV in the groove of the manifold AND the rubber gasket OVER the pipe/flange, there is little to no leakage at all.
Straight up RTV will work for a while, but in my experience ALWAYS fails on the denco/wirges type flanges.. Especially with rubber mounted motor and rubbermounted pipes.
Use the blue rubber (made of high temp silicone) gasket that is usually used to seal the headpipe to muffler connection on the stock early H1 and H2 pipes. This gasket hides beneath the chrome connection-clamp and unseen on stock mufflers, but as you can see on the dencos it goes OVER the connection.
I used this trick on both of my bikes with Dencos (one set is from Jim). Its works GREAT as there is a "step" molded into the inner bore of the rubber gasket.
With a bit of high temp RTV in the groove of the manifold AND the rubber gasket OVER the pipe/flange, there is little to no leakage at all.
Straight up RTV will work for a while, but in my experience ALWAYS fails on the denco/wirges type flanges.. Especially with rubber mounted motor and rubbermounted pipes.