760 with B-Pipe

[TL91]

Was wondering what the best method of putting a B-pipe manifold onto a 760 cylinder is, drilling out the B-pipe manifold holes to accept an M10 size bolt through them or helicoil the 760 cylinder threads from an M10 to M8? Pros/Cons to one over the other?

 

[OCD Solutions]

To best answer that question, we first need to know two things;
1) Do you already have the appropriate drill bit?
2) Do you already have the correct sized helicoils?

If you answered yes to either one of those questions, then that is the best method.

All jokes aside, the drill is the cheapest and easiest but requires the most commitment.
Helicoils would be my choice just because it can be undone.

 

[Quinc]

I run the helicoils on my 760 cylinder. Either way you will want to helicoil the two center top bolt holes for m8 bolts.

 

[Storbeck]

I'm running one with helicoils. Also "port" the manifold to match the shape of the port on the cylinder, and I believe @JetManiac now has 62t shaped gaskets with 8mm bolt holes.

 

[JetManiac]

Best method is to helicoil. You do not have to drill or tap cylinder. M8 fine thread helicoils screw into the M10 fine thread holes directly with no modification. So you always pull the helicoils out and cylinder is back to stock. No modding of manifold and M8 bolts much easier to use on a bpipe mani.

 

[TL91]

Awesome, thanks for all the feedback everyone!

 

[bernard]

I just ported my b pipe to fit, I have thread inserts. The porting is fairly extensive, you want to have some previous experience here.

 

[Req]

I know you can send the bpipe off to be matched and bored at 51mm. I imagine whoever offers that service could also port the manifold to the 760 size exh port.

Just another option.

 

[Storbeck]

I just ported my b pipe to fit, I have thread inserts. The porting is fairly extensive, you want to have some previous experience here.

When I did mine I just moved the floor down maybe 1/16" ish to match and blended it, I wouldn't call it extensive at all. Is there more to it than that?

 

[Req]

When I did mine I just moved the floor down maybe 1/16" ish to match and blended it, I wouldn't call it extensive at all. Is there more to it than that?

When I did my 62t I remember bringing the ceiling of the mariner 6m manifold up to match about 1/8", it was already pre ported for the x cylinder. That was however last year and I have slept since then.

I dont remember it being difficult with a dremel and a stone bit. They caked up really fast and I went through three or four of them but it only took about 45 minutes.

 

[bernard]

Not to thread hijack, but what should the head pipe transition be bored to for his 760 and my 809? I was thinking 50mm?

 

[Storbeck]

 

[Storbeck]

Not to say that what I did it's "the correct way" but that was all it took to get what I thought was a pretty good match, at least as good as the match was to a 61x unmodified.

 

[bernard]

When I did mine I just moved the floor down maybe 1/16" ish to match and blended it, I wouldn't call it extensive at all. Is there more to it than that?

I think matching the top transition on both sides with the head pipe cleanly is difficult if porting that part. Yah the two header ports aren't too bad.

 

[bernard]

Here are my exhaust ports, going to do the head pipe transition tonight.