Donuts

[YammiMoose]

How can I tell if the donuts are blown? I took my first ride this weekend and don’t remember this sled being this loud at any speed under about 50mph. I would give only what I describe as a droning noise that seemed to bother me more as the day wore on.

Also, other than taking off the seat and tank is there any other of checking to see if they are blown?

Thanks,

-Moose

 

[michaelscs]

Same here! Same noise, Same question on checking.
Thanks, Mike

 

[Highmiler]

Checking donuts

What I do is plug ends of exhaust with stuffed rags, then I remove hood and start sled and check for sound or smell of exhaust. Hope this helps!!

 

[apltx08]

Another indication is BACK FIRES...

 

[Viper_Dave]

BINGO on the backfire. I've had mine replaced twice. First time it happened was during our saddlebag trip to Muni last year. Got them replaced last spring, took the sled to Houghton for the TY ride. Breaking in a new belt, so I WASN'T hotrodding it! Headed towards Phoenix at around 50-60 mph. Let off for the Phoenix/Vansville intersection.brrr-POWPOWPOW!! By Saturday it was unridable. Dealer replaced 2 clamps this time. The first repair had 1 cracked clamp. I hope this ISN'T a recurring issue. There are already a couple threads on this issue, but no real definite solution.
Dave

 

[Attacker]

Just changed mine today. Have 7500 mi. on. Favarcat and myself did it in about 3 hours. Not as bad as I thought it would be. The biggest thing is the room to get the old ones out and the new ones in. We took two bars and put them on both sides of the flex tube and pushed them foward just enough to slip the new donuts in. His attak started to back fire and blurp if he really got on it. We ride together alot so we decided to do both of our sleds. My donuts were just starting to go.

 

[apex yooper]

attacker,

Did you grind the tabs on clamps, or use RTV?

I didn't notice any louder noise, but 2 were completely gone, one had a scrap left, and one was 2/3 gone. My clue was backfire sometimes when getting off the throttle.

 

[favarcat]

Yes, we ground some off the clamps. We did not use RTV. Were your y-pipes alright?

 

[apex yooper]

I didn't see anything wrong with my pipes.

 

[YammiMoose]

Re: Checking donuts

What I do is plug ends of exhaust with stuffed rags, then I remove hood and start sled and check for sound or smell of exhaust. Hope this helps!!

Tried it last night, no leaks. Great suggestion!

Thanks,

-Moose

 

[Apex Gt Rick]

I just did mine with 5000 miles. 2 were shot, I did grind clamps but did not use rtv. Got all done and it was still loud. Found out I also broke my exhaust were it goes from 2 into 1 so I welded it. All I can say is I almost took it apart there but did not need too but wished I did when I got done.
Rick

 

[ROCKERDAN]

Mine sounded rather loud from time to time my first ride out....took it apart and my exhaust gaskets(donuts) were pretty worn....one much worse then others...

I found that if you want to install new donuts,its best to remove the 4 FLEXpipes from the HEAD,which makes it alot easier to put the new donuts onto flexpipes without hurting them....it only takes a couple extra minutes to remove the flexpipes from head with a swivel,dont drop the copper exhaust manifold gasket when removing the flexpipes.

step by step:

-remove front hood & sidepanels
-Remove exhaust pipe caps(2 allen screws)
-Remove tailight shroud(#3 philips)
-remove seat(unplug wires above right footwell)
-remove handlebar chrome cover(#3 philips)
-unscrew ign. key & remove upper shroud
-remove both side plastic shrouds #3 philips(above feet stirrups)
-remove gas tank shroud(take off gas cap and rubber gromet under cap)
-now drain fuel tank down to 2 gallon max
-unhook fuel line@rear tank & unplug wire,remove foam spacer
-unhook fuel return line at fuel rail(front)and unplug fuel gauge wire
-unbolt tank bolts at rear and slide tank back off tunnel,set aside
-remove the aluminum cover(4bolts)that covers the exhaust flexpipes
-remove 4 clamps attaching flexpipes to main pipe(allen bolts)
-remove 4 rubber grommets in tunnel
-loosen the 2 allen bolts and two 12mm bolts under grommets
-now slide the main exhaust backwards away from flexpipes
-IMO best to remove the flexpipes now from HEAD(use swivel socket)

Once flexpipes are removed from head its easy to remove old donuts and install new ones without ruining them....

Im not sure yet if I will grind down my exhaust clamps slightly yet...this would allow the clamp to tighten TIGHTER around donuts...I have a feeling this MIGHT cause the donuts to wear out quicker....still looking for more feedback on the grinding down theory.

this all sounds like alot of work,but can all be done with some knowledge in under 30 mins....took me about 20 mins to get mine to this point...but I have done much of this work before.

hope this helps anyone who wants to do this alone..I also recommend anyone with an apex to go out and buy a #3 philips head socket for all those large black philips screws that hold on all the panels.

some pics below...

Dan

 

[MUSKOKA APEX RTX 07]

Dan: As always a great how to on changing the donuts for exaust! to all i was at Dans today and as he stated its pretty easy to change especially with this great direction from Dan.gotta love when someone takes the time to go through step by step to help people out like my self who dont know Jack about this motor, we all came from riding Machs and let me tell you this thing is Way more in depth than a 2 stroke!!

 

[blue er]

excellant work Dan
My sled doesn't appear to have a problem backfiring yet, but on cold startup i hear a ticking noise in the exhaust that goes away as the engine heats up.
with all the snow gone for awhile i may just tear into this donut problem and try to do a pictorial for everyone.
** sled has 4400 km on it**

 

[Jens]

seems to have simular problem on my nytro with only 2500km on it