Splitting mod pipe coupler

[JSmith5690]

My buddy's factory Mod pipe keeps splitting the coupler between the head pipe and the manifold. The latest one only had about 2 hours riding time on it. Are there any any tricks to minimize this from happening? What are common problems for this issue: Misalignment? over tightening clamps?

 

[Dustin Mustangs]

Make sure there aren't marks on the hull from it hittting due to engine vibration or hard landings. The headpipe and the chamber also need to be pretty close if not touching around the entire circumference of that connection. The smaller that gap the better for performance and longevity of the coupler. A good way to check this is to install the chamber as you normally would minus that coupler so you can visually see the size of that gap.

Is it blowing out in the same location? If so, where (ie top, bottom, port, starboard, ect...)?? Does the ski backfire at all???

 

[JSmith5690]

I think the break started on bottom 180*. But it was soon split 360* around. I don't think it was a backfire issue. Motor and pipe do seem to vibrate quite a bit.

 

[butti]

use only high quality clamps with tapered shoulders.overtightened cheapo auto parts store hose clamps can cut into the coupler

 

[NJJer]

"It is very important that the chamber body and headpipe seat flush and tight inside the coupler. Otherwise, loss of performance and coupler failure may occur. "


Taken from here:



http://www.factorypipe.com/media/instructions/yamaha/701BL02.pdf

#1 reason they fail.