any ides where i can find 26mm intakes i don't have to modify to fit my 77 650? elongating the holes ended up in a leak and a blue header. damm bike! it's one thing or another! but it is a labor of love.
The problem is that the rubber is distorted with age to fit against the engine it was mounted to originally. You have to take the mating surface to a belt sander to re-surface it. I went very lightly and it only took a couple seconds.
Then I cleaned them and made paper gaskets to make them seal for sure. I glued the paper gaskets to the manifolds with hardening gasket cement.
Then I put a super thin layer of anti-sieze on the head's mating surface so the manifolds will come off easily without damaging the gasket.
They seal perfectly. I had to put big washers on the screws to prevent distorting the elongated holes on the flanges.
