Sealing Crossover Pipes??

jkevinlilly · Post by **jkevinlilly** » Mon Jul 13, 2009 6:43 pm

When I picked up Pinky earlier this year the exhaust crossovers were leaking. When I took it apart the connections were full of wornout RTV, and the o-rings were so old they just kind of crumbled. I put new o-rings on, along with some of the original Suzuki gasket material that Lane had gave me with the bike. Pulled the pipes together with a rachet strap, then tightened down the bolts. I thought I got everything in place without damaging the gasket material. At that time they were sealed with no visible leaking, even on a cold morning. Noticed today they are leaking blue smoke again when the bike is warming up.

Suggestions on how to do it this time so it will last???

Kevin

pjmcburney · Post by **pjmcburney** » Mon Jul 13, 2009 10:10 pm

Kevin,

I've used RTV silicon with excellent results - toss the OEM stuff in the bin.

As it's pretty cheap, I tend to get stuck in and run a thick-ish bead (approx 7-10mm) around the scalloped edge of the crossover tubes before pushing them into place.
New o-rings will help as well of course.

No smoke has ever leaked from mine, and more importantly, no 'gunge' (leftover two-stroke oil) has leaked out either.
I pulled mine apart when I did the frame swap and there was a bit that had squeezed through onto the inside of the tube itself, but it was dry and hadn't affected anything as far as I could tell - there was no evidence of any leakage, all the black stuff was inside the pipe/s.

The beauty of it as well is it doesn't completely stick, I just rubbed it all off and reapplied it.

I haven't tried the OEM stuff, but from what I've heard and personal experience, the RTV silicon works at least as good and probably better for longer.

Cheers
Paul

Post by **oldjapanesebikes** » Mon Jul 13, 2009 11:23 pm

I also used RTV silicon on my GT550 rebuild, and so far at least no sign of any leaks. Recommended.

jkevinlilly · Post by **jkevinlilly** » Tue Jul 14, 2009 4:00 am

RTV it is then. I already have most tube on hand anyway, since I use it around the crush gaskets between the exhaust and the cylinders.

Kevin

pjmcburney · Post by **pjmcburney** » Tue Jul 14, 2009 3:37 pm

jkevinlilly wrote:RTV it is then. I already have most tube on hand anyway, since I use it around the crush gaskets between the exhaust and the cylinders.

Kevin

Kevin,

With new or good condition gaskets at the pipe junction into the barrel, you shouldn't need anything else (like RTV) to get a good seal.

I just used new gaskets on my pipes and they seal fine - but I also have screw-collars in very good condition.

Trap for young players...

There needs to be an adequate gap between the screw-collar and the edge of the barrel - approx 2-4 mm all the way around, after the collar bolts are tensioned down. The collars also need to be perfectly flat on their back (flat) surface otherwise you're likely not to get enough tension on the exhaust gaskets to seal properly.

Check your collars for 'flatness'. Over time, especially if someone has overtightened them in the past, they tend to bend where the bolt holes are, to the point that they rock back and forth when placed on a flat surface. This means that when you try to tighten them, they can contact the barrel at those points preventing adequate tension on the gasket.

Good luck
Paul

jkevinlilly · Post by **jkevinlilly** » Tue Jul 14, 2009 6:47 pm

Paul,
Good points.

I used the RTV when reusing an old crush gasket.

It worked.

Kevin