to donut or not to donut...thats the question

[SledFreak]

new ones and then make sure you mod the clamps by filing the bushing a little to make the clamps tighter.

X2 i had to grind quite a bit off of my clamps to make them tight enough.

Ya, what's this mean?

When i was putting my exhaust back together, i tightened the clamps that go around pipes where donuts are and they were still loose. Where the bolt goes through the clamp was making a complete circle and couldnt tighten enough. so i ground each side of flange where bolt goes through so there was more room for the clamp to close up. Worked out good.

So the flange/clamp has a ridge on it that you ground down to make flat, so you can squeeze the clamp tighter?

 

[mach9]

During a new donut install...
Has anyone tried packing the clamp rings full of high heat exhuast silicone?
If yes, any results?
RX-1, Apex guys may have more years experience of this issue.

 

[apltx08]

Grinding the clamp spacer to make them tighter really improves on durability...I DO NOT reccomend any type of silicone in the clamps as it'll BURN out and make your clamps LOOSE and distroy the donuts caused by LEAKAGE!

 

[SledFreak]

Anyone got any pics...

 

[Unluckydiablo]

<-- Dumb guy, but why do you need to replace the donuts? What happens if you don't? Please forgive my ignorance....

 

[SledFreak]

exhaust leak = lose hp and becomes very loud..

 

[Unluckydiablo]

Got it, thank you.

 

[mach9]

Grinding the clamp spacer to make them tighter really improves on durability...I DO NOT reccomend any type of silicone in the clamps as it'll BURN out and make your clamps LOOSE and distroy the donuts caused by LEAKAGE!

I respectfully disagree.
So what if...
Step 1, grind down the clamps to allow for more clamping force.
Then add heat silicone as well.
Since as you squish down the donut and goo comes out all over the place. If you do your grind mod to the clamps correctly.
The clamps will still be super tight on the donut regardless if heat silicone is in there or not.
This is the beauty of free flowing sealants.
And who can monitor daily how long it takes to burn out purpose built silicone anyway?

 

[yox185]

Hey guys...FX Nytro XTX with 2000miles and I'm instaling and excell header...do I reuse the stock donuts or should I change the 3???

Daranello, you will see when you take the donuts off, they will need changing. And anyway would you really go through all that work and not change them? That would be like pulling the motor on a car and not changing the rear seal while you have it out.

 

[apltx08]

Grinding the clamp spacer to make them tighter really improves on durability...I DO NOT reccomend any type of silicone in the clamps as it'll BURN out and make your clamps LOOSE and distroy the donuts caused by LEAKAGE!

I respectfully disagree.
So what if...
Step 1, grind down the clamps to allow for more clamping force.
Then add heat silicone as well.
Since as you squish down the donut and goo comes out all over the place. If you do your grind mod to the clamps correctly.
The clamps will still be super tight on the donut regardless if heat silicone is in there or not.
This is the beauty of free flowing sealants.
And who can monitor daily how long it takes to burn out purpose built silicone anyway?

The exhaust gets extremly hot and burns/distroys any type of sealant/silicone, so whats going to fill that gap after its gone, you tighten your clamps as tight as possible with SEALANT taking up space, so when its gone your clamps will be somewhat LOOSE and over time start leaking and burning out DONUTS! We did a RX1 with exhaust silicone and another without with same set-up of clamps, both got done at the same time, the one with SILICONE failed at 3000kms or so and the other without is still going with 5000kms...is it just a fluke or better without sealant?...we re-did the 1 that failed WITHOUT sealant and we'll see how long it last this time around, it has 2000kms so far so good everything is nice and tight and so is the other with 5000kms...we just finished the fall tune-ups last wekend.

 

[mach9]

apltx08 Thank you.
Glad to hear your results.
This is the kind of info. that helps to better decide my and others fate.
Maybe what is happening there is that the extra layer of silicone is in fact reacting badly to the donut gasket.
Either by extra heat due to insulation or some other chemical breakdown.
Thanks again...!!

Darn @#$*# donuts!!
Just another chink the reliability claims.
Who ever said pulling the fuel tank is normal seasonal wear and tear maintenance?

 

[arteeex]

I don't see the reason for using exhaust gaskets on this assembly. From my perspective a slip joint (or even a welded joint) would have been fine given the adjacent flex joints can absorb misalignment and displacement in the system.

I would be very interested in the results of some brave individual sawing off the flanges and either retrofitting a slip joint on the header or welding the flex joints on directly.

Who's up for the challenge?

 

[mach9]

I don't see the reason for using exhaust gaskets on this assembly. From my perspective a slip joint (or even a welded joint) would have been fine given the adjacent flex joints can absorb misalignment and displacement in the system.

I would be very interested in the results of some brave individual sawing off the flanges and either retrofitting a slip joint on the header or welding the flex joints on directly.

Who's up for the challenge?

Now were talkin...
Drop the expensive power robbing flex joints out right.
Use hook springs on certain key joints and/or larger flex rubber mounts on header mounts.
Guinea pigs required..!!

 

[garyw]

donuts

Changed mine at 2700 miles on my 09 fx at the end of last season.Used neverseize on the donut and pipes as a cushion. Worked really go on my apex.

 

[sledheadgeorge]

Use new ones and install a flex joint in the pipe and go another 10,000 miles without changing them again. Well worth the added expense.

talk to me....whats with the flex joint

OK here is my previous thread about the pipe were I added the flex joint to my turbo. I used to change donuts every year on my turbo before I did this. You can see it on the pipe just before the bend for the turbo mount. http://www.ty4stroke.com/viewtopic.php? ... ht=#341989
For the stock sled you would have to locate it near the muffler and add a shield to it under neath so the studs won't touch it. Lots of pics for stock ideas. I am thinking of doing this to my son's Apex GT, but he has no issues yet with the donuts and Y-pipe. "If it an't broke, don't fix it" As far as I'm concerned Yamaha should install a flex joint from factory at the back near the muffler. There is just too much flex in the chassis for just the front flex pipes to handle. Snowmobiles take an awfull pounding, and because Cat and Doo do not have a rear exit exaust on thier 4-strokes I've never herd of a donut problem with their engines. This would eliminate some of the frustrations first time 4-stroke byers experience. Hope this helps.