MAC 4into1 Exhaust Leak

[Guest]

Quick question.

I can't seem to get my MAC 4into1 pipes to not leak a small amount at the connection between the muffler and the header.

Maybe I'm not cranking the clamp down tight enough? Torque spec?

Maybe I'm inserting the muffler too far onto the header? It is currently sleeved onto the header as far as it will go.

Any wisdom and advice would be great! I just finished the motor rebuild and it is running great! I just want a sealed exhaust system!!

[tom203]

Is there a large difference between ID of muffler and OD of header ? like 1/8 inch?

[OldVet66]

You could try a little muffler cement when you slide them together. If you can keep them from leaking for a while, they will carbon over the joint and seal themselves.

[tkent02]

I think that's just a MAC thing. Weld it.

[born2lose]

I have a Mac exhaust and I had to hammer mine down pretty hard for it not to leak

[BTreadz]

I reinstalled the pipe with some exhaust cement. It is definitely better, but still has a small leak...

[OldVet66]

It will most likely seal itself in time if it doesn't blow the cement out before it gets carbon coated inside. You can always try it again if it doesn't or go the permanent way and weld it. Posting back as soon as you did points to not letting it set up long enough before you tried it.

[BTreadz]

Better!

No leaks now. Man, is it running well!!

[JTGS850GL]

So what did you do to seal the leak?

[BTreadz]

I took oldvet66's advice.

I used some exhaust cement and clamped a little bit tighter than I was before....I'm not feeling any leaks now.

[londonboards]

Exhaust Leaks

So from what you have written am I to assume that even the slightest leak will effect the performance?

I have several small leaks which I can hear and feel but I am not bothered to repair as long as they are not unduly affecting the performance noticeably.

Greetings

[BTreadz]

Exhaust leaks....

I don't think a small leak or two will cause great performance losses on 30+ year old bikes, but hey, I like to reach for perfection!

[JTGS850GL]

Small leaks can cause some back firing on deceleration. I don't think a small leak would have any measurable change in performance beyond that.