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My 72 and 73 TNT's have the exhaust outlets that are threaded into the cylinder cases (I believe this is common on the twin cylinder Oly's , TNT's Nordics of the era). These outlets dump into a y pipe that connects the 2 cylinder outlets to the kidney shaped exhaust pipe. The whole system is held together by springs from the motor to the muffler. My problem is I get exhaust blow by at the inlet and outlet ends of the y pipe which results in an oily mess all over the exhaust pipe, fuel tank etc. I have tried various sealants at each end of the y pipe joint but my conclusion is they (the ones I have tried) are not really tolerant of vibration or the unburnt gasoline escaping out the exhaust. Has anyone found a reliable (or even half reliable) solution to this?

I've found short term relief wrapping the joints in foil and clamping it in place with a hose clamp but it really is just a "band aid" fix as it too peels off owing to aluminum foil not being up to task.

Love to know if there is a trick to resolve this!
 

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Did you try Permatex Ultra Copper?
 
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How strong are your exhaust springs? - If you are not swearing at them trying to get them on, they are too loose.

If that doesn't work, I have done the band-aid you described. However, I have not done this on your exact model sleds.

Instead of flimsy aluminum foil, I used thin aluminum cans (soda pop, beer, etc).
Goop up the joints good with high temp sealer. (Ultra Copper like OSN suggested) then wrap with the aluminum to keep it all in place.

Two hose clamps, one on each end to hold it all. Held up well, but did need replacement every once and awhile on the one lungers that vibrated a lot.
 

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Good call out on the springs. They are stiff but I don't need to swear at them :lol:. In fact, I can get the set up to jiggle around without a lot of effort. So will watch for and source better springs to see if that helps. As for sealant, the one sled has the remains of a red sealant in it (I have no recall what it was but some form of RTV product seems to come to mind). The other has the permatex gray motoseal 1. I haven't tried the permatex ultra copper and will look at spec sheets for it and expect i'll give that a try. The beer can sleeve sounds like a logical try for an encasement solution. I was focused on flexibility. Stands to reason that if better/new springs are super tight, with new sealant and the aluminum sleeve Sightation suggests it has to be an improvement over current situation.

Thanks for suggestions.
 
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