So the project RD350 has an exhaust leak. Actually 'leak' doesn't quite describe it. It's more like the exhaust isn't sealed at all judging by the smoke coming out of the junction. The exhaust gaskets are brand new, from a gasket set from India. I did a quick comparison with some factory Yamaha ones I had and they seemed the same. The clamp seems to be flush against the cylinder so I'm guessing the gaskets were not thick enough. The bike is a 'bitsa' so I don't know if the clamps are for the headers if there were different ones. They seemed to fit properly but they also seem to have a curve which I didn't notice until I inspected the junction after firing the engine up. There is a tiny gap in the middle while the sides look flush with the port. The clamp did not slide off the end of the header so it seemed to be the correct size, and the bolt holes also lined up perfectly.
Has anyone seen this before. What would a solution to the problem be? Doubling exhaust gaskets seems like it would be too thick. If the Indian gaskets were incorrect they were close enough in size to the Yamaha ones that there was no noticeable difference so using a Yamaha gasket seems an unlikely solution.
Do not double up on the gasket.
I would try putting some of the "the right stuff" gasket maker with your exhaust crush gasket to see if that helps with your issue. I've used all sorts of different exhaust crush exhaust gaskets, ranging from Chinese to factory ones and they all sealed up properly.
Also, to add to the above; a cure time of 24 hrs after application of "Permatex- The Right Stuff" is optimal before starting it after tightening your flange bolts/ nuts.
The Right stuff works, but I opted for the orange high temp version. Stinks to high heaven, but once cured... no leaks!
Thanks for the input. I have to go to O'Reilly's today anyway so I'll grab some 'The Right Stuff'. Permatex's website shows black, grey, and red, in different applicators. I'll see what the local store has in stock and choose from there.
The black 'The Right Stuff' seems to have worked.
That being said; I noticed that both the Indian and Yamaha gaskets seem to 'choke' the exhaust port. Say for giggles I turned some aluminum 'gaskets' on my lathe out of aluminum bar stock that did not choke the ports and used 'The Right Stuff' to seal everything up; what would the possible problems be?
Glad that suggestion helped out! :)
Quote from: Diablo007 on September 22, 2020, 02:05:19 AM
The black 'The Right Stuff' seems to have worked.
That being said; I noticed that both the Indian and Yamaha gaskets seem to 'choke' the exhaust port. Say for giggles I turned some aluminum 'gaskets' on my lathe out of aluminum bar stock that did not choke the ports and used 'The Right Stuff' to seal everything up; what would the possible problems be?
Many other bikes use hollow copper o-ring exhaust gaskets. You might try getting the right diameter of them and try. Whichever, always check carefully that previous gaskets have been removed. I once found three gaskets compressed into each port on a GL1000.
BAHAHAHA I can hear the exhaust leak now.
@quocle603
Elaborate please. Was your comment directed at using the copper gaskets found in 4-strokes, or regarding turning aluminum spacers and using 'The Right Stuff'. If it's the latter, similar has been done by a noted tuner acquaintance. In their case they JB welded the spacers in for one of their builds, currently they weld up the recess and use copper/silicone gasket sealer. I'm hesitant to use JB weld or weld up the recess on a street bike as it would be hard to reverse. They replied to my email after my last post.
I thought he was referring to the Gold Wing with three gaskets per port. :umm:
DOH...that makes more sense. I thought there might be a reason for not using a round/tube copper gasket in a 2-stroke, or bad experience with using a spacer and sealer instead of a crush gasket.
Laughing at the goldwing.
@quocle603
Thanks for the clarification. Wanted to make sure I hadn't missed something important with my plan as I'm thinking of doing this for the next engine that needs new gasket and seals.
Do whatever works. People are all up in arms about things when it comes to doing it the RIGHT WAY.