Yamaha runs on Junkin Donuts...

[markddapexgt]

Had to ride the GT back on a long run even though I knew there was a donut problem. This I think caused the failure of the LH Y pipe - eventually replaced with Bender Stainless. I had checked the donuts( or so I thought) 1K ago but only removed the clamps and visualy inspected.
By taking a look at the pix you can see that you can spend more $$$ on good beer and less investing in Titanium or Stainless comodoties by actually removing the headers and checking them totally.
If you open the clamps and do not remove the headers you cannot see the entire fibre donut and it could well be failing. I mocked this up on the bench using the donut that failed causing my y pipe damage and you can see that it would possibly pass a quick visual without being removed.

I am about to fabricate replacements in pure copper and test in my sled as I am sick of replacing these things + the last episode replacing the Ypipes see seperate post on installing Bender Y pipes.
My idea here is that the copper is self annealing so will stay soft enough to absorb the movement and protect the flanges while dissipating heat more readily and evenly. I will post on any results obtained.

 

[blackattak]

How do you tell when this is going on you when you are driving it. Sound? Error Code? To date I don't think the dealer has ever changed them & now have 8000 km or 5000 miles on the sled.

 

[Honk]

Just did mine, 4 thousand miles. It will backfire on decell. You will hear rattling at idel. Sounds like my old RX-1 heat sheilds, but its the clamps rattling on the pipes. all but one were totally GONE

 

[markddapexgt]

I have replaced numerous times now on different sleds and never have I seen an error code. Generally it is a change in the engine/exhaust sound that gives it away. This has been covered on many other posts but you can check by blocking the ends of the exaust and checking for fumes/noise coming from the area below the front of the gas tank. Check the many other posts on this that go into greater detail.
There is no real co relation to mileage and occurance unfortunately making it even more unpredictable. But its fairly simple to dismantle and check. My point being that while the clamps are removed you still cant tell if the donuts are intact. You need to remove them and that means for the $40 you may as well replace them. Hope this is helpful.

 

[Honk]

very easy to undo clamps and head bolts to slide whole unit back. this gives enough room to replace. .

 

[markddapexgt]

I agree. you get stacks of room by loosening the 2 allen screws, the two muffler clamp bolts and removing the 4 muffler bolts. This also allows you to replace the new donuts with copper silicone without fear of damaging them.