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Throttle response STOCK vs Free Flow Mufflers

Here's another example of my XTX and a buddies stock 800 summit. This was the last afternoon of riding of the year, and we were doing some playing around with suspension settings, and I did a few laps in the woods trying to get a feel for comparing the summit to the XTX. Here in this video, you can see me taking the summit up a short sharp incline, giving the throttle a quick stab, and it instantly launches. Did the same thing with the sidewinder - and the engine never got into the power enough to really get the front end lifted. The slow-mo doesn't help with hearing the engine response, but that is how the video was sent to me.

I don't want to sound like I am sour grapes, as this is an amazing snowmobile! And if all I did was big trails, or rode out west with huge meadows and open ground, it's gotta be about perfect. But, if there is one and only chink in the armor that I can find, this is it. I remember way back to the SRX days an we ran the 8BU's (old vmax4 weights maybe?) and they really gave that sled what we called the "dirt bike" feel. Super snappy and fun to ride corner to corner, but absolutely no top end. The stock set up would run you down at 100 like you were tied down. Maybe there is a weight or clutch set up like that out there that can give some snap back. Even if it looses some top end, I'd be good with it.

By the way.. I almost hate to admit it, but I snowchecked a 850 Freeride - first non-Yamaha sled for me in 20 years. I don't know if I'm selling the sidewinder yet, but either way, I'll have some good options for what to ride next year!

 

if the clutches were set up to give more engine braking , the clutches stay engaged , and the rpm's stay higher , so when you gun it , it's closer to boost , and you hit the bumps on the way up not down.
when I let off the gas , it feels like one of the clutches completely lets go of the belt , and the revs drop off immediately . so i am guessing its the primary.
 
Ok...I want to be clear. Clutching "delay" is one specific thing, and I think many here are describing this...I completely agree with wanting more engine braking, higher revving at slow speeds, all that stuff will have the sled feeling more peaky and quick hitting.....I dont feel the sled is lacking at all in this respect, especially with a tune.

But this is NOT the issue IMO....I first thought I could clutch around it too, but after many tries with the help of alot of goodies from Buddy Dale at dalton, I came to the conclusion the "delay" happens way before it has anything to do with clutching.

Its a thumb to engine delay IMO....it can be "heard" by the ear easily when sitting still or even riding down the trail, you watch your thumb mash it, and hear a brrrrrrrooooooommmmm.....Im trying to type out the delay in letters..LOL....

If I could video two take offs, SW vs my 1200 4tec, there is nothing but GO vs a marked time delay until GO on sw.

The more I watch the stocker vs modded sled in video....I truly think it has to do with the LESSER backpressure on these free flowing exhausts....I agree with you SJ on the slight blipping as he is trying to give us a sound test....but He sorta blips them on all, and while its not perfect timing and is closer blip on stocker, you can HEAR the marked delay time with your ear. I never like to use the word BOG but it rather reminds me of an old school BOG sound on a dirty 2s engine that has not ever had its main jets cleaned.

You can watch the last sled how it sounds, and after the delay the sled then transfers and lift skis....while the stock sled transfers right away, and has less of an audible BOG sound delay. Really makes me think exhaust/no backpressure.

Good part is, next season will have a stock sled of my own, and I can take video to hear what takeoff is like vs modded....and get to the bottom of this...and if it ends up being a muffler thing, I will talk with the gurus at Sandale to see if they can come up with a way to help reduce this...I want more then anything to have snap, then top end.
 
Last edited:
I think that's the nature of 4stroke too. And that throttle feel is what makes people feel it's "heavy" or there is turbo lag. It doesn't just rip out of your hands but keeps pulling. Could be cam or timing profile causing that.
 
ROCKERDAN said:
Ok...I want to be clear. Clutching "delay" is one specific thing, and I think many here are describing this...I completely agree with wanting more engine braking, higher revving at slow speeds, all that stuff will have the sled feeling more peaky and quick hitting.....I dont feel the sled is lacking at all in this respect, especially with a tune.

But this is NOT the issue IMO....I first thought I could clutch around it too, but after many tries with the help of alot of goodies from Buddy Dale at dalton, I came to the conclusion the "delay" happens way before it has anything to do with clutching.

Its a thumb to engine delay IMO....it can be "heard" by the ear easily when sitting still or even riding down the trail, you watch your thumb mash it, and hear a brrrrrrrooooooommmmm.....Im trying to type out the delay in letters..LOL....

If I could video two take offs, SW vs my 1200 4tec, there is nothing but GO vs a marked time delay until GO on sw.

The more I watch the stocker vs modded sled in video....I truly think it has to do with the LESSER backpressure on these free flowing exhausts....I agree with you SJ on the slight blipping as he is trying to give us a sound test....but He sorta blips them on all, and while its not perfect timing and is closer blip on stocker, you can HEAR the marked delay time with your ear. I never like to use the word BOG but it rather reminds me of an old school BOG sound on a dirty 2s engine that has not ever had its main jets cleaned.

You can watch the last sled how it sounds, and after the delay the sled then transfers and lift skis....while the stock sled transfers right away, and has less of an audible BOG sound delay. Really makes me think exhaust/no backpressure.

Good part is, next season will have a stock sled of my own, and I can take video to hear what takeoff is like vs modded....and get to the bottom of this...and if it ends up being a muffler thing, I will talk with the gurus at Sandale to see if they can come up with a way to help reduce this...I want more then anything to have snap, then top end.
Click to expand...

After all observations are said and done , I believe , I have the answer.
IT is a combination of many components of the engine and transmission , that was designed by Yamaha , TO GIVE ALL OTHER STOCK SLEDS A LITTLE HEAD START , TO MAKE THEM THINK THEY HAVE A CHANCE !!!!!
There could be a catch up chip(same as a break in chip) that , wears off , after some real competition is released .
Don't know how long that will be !
Will we ever find out ????
I am not even sure if the chip wears off , when a made in Japan sled is released by Yamaha , that has 4stroke , 4 cylinders , factory Turbo, power steering , and ........ ???????
A WHOLE BUNCH OF CARBON FIBRE !!!!!
 
ROCKERDAN said:
Ok...I want to be clear. Clutching "delay" is one specific thing, and I think many here are describing this...I completely agree with wanting more engine braking, higher revving at slow speeds, all that stuff will have the sled feeling more peaky and quick hitting.....I dont feel the sled is lacking at all in this respect, especially with a tune.

But this is NOT the issue IMO....I first thought I could clutch around it too, but after many tries with the help of alot of goodies from Buddy Dale at dalton, I came to the conclusion the "delay" happens way before it has anything to do with clutching.

Its a thumb to engine delay IMO....it can be "heard" by the ear easily when sitting still or even riding down the trail, you watch your thumb mash it, and hear a brrrrrrrooooooommmmm.....Im trying to type out the delay in letters..LOL....

If I could video two take offs, SW vs my 1200 4tec, there is nothing but GO vs a marked time delay until GO on sw.

The more I watch the stocker vs modded sled in video....I truly think it has to do with the LESSER backpressure on these free flowing exhausts....I agree with you SJ on the slight blipping as he is trying to give us a sound test....but He sorta blips them on all, and while its not perfect timing and is closer blip on stocker, you can HEAR the marked delay time with your ear. I never like to use the word BOG but it rather reminds me of an old school BOG sound on a dirty 2s engine that has not ever had its main jets cleaned.

You can watch the last sled how it sounds, and after the delay the sled then transfers and lift skis....while the stock sled transfers right away, and has less of an audible BOG sound delay. Really makes me think exhaust/no backpressure.

Good part is, next season will have a stock sled of my own, and I can take video to hear what takeoff is like vs modded....and get to the bottom of this...and if it ends up being a muffler thing, I will talk with the gurus at Sandale to see if they can come up with a way to help reduce this...I want more then anything to have snap, then top end.
Click to expand...


I know what the problem is now...and will be seeing of theres a solution soon....
 
ROCKERDAN said:
Ok...I want to be clear. Clutching "delay" is one specific thing, and I think many here are describing this...I completely agree with wanting more engine braking, higher revving at slow speeds, all that stuff will have the sled feeling more peaky and quick hitting.....I dont feel the sled is lacking at all in this respect, especially with a tune.

But this is NOT the issue IMO....I first thought I could clutch around it too, but after many tries with the help of alot of goodies from Buddy Dale at dalton, I came to the conclusion the "delay" happens way before it has anything to do with clutching.

Its a thumb to engine delay IMO....it can be "heard" by the ear easily when sitting still or even riding down the trail, you watch your thumb mash it, and hear a brrrrrrrooooooommmmm.....Im trying to type out the delay in letters..LOL....

If I could video two take offs, SW vs my 1200 4tec, there is nothing but GO vs a marked time delay until GO on sw.

The more I watch the stocker vs modded sled in video....I truly think it has to do with the LESSER backpressure on these free flowing exhausts....I agree with you SJ on the slight blipping as he is trying to give us a sound test....but He sorta blips them on all, and while its not perfect timing and is closer blip on stocker, you can HEAR the marked delay time with your ear. I never like to use the word BOG but it rather reminds me of an old school BOG sound on a dirty 2s engine that has not ever had its main jets cleaned.

You can watch the last sled how it sounds, and after the delay the sled then transfers and lift skis....while the stock sled transfers right away, and has less of an audible BOG sound delay. Really makes me think exhaust/no backpressure.

Good part is, next season will have a stock sled of my own, and I can take video to hear what takeoff is like vs modded....and get to the bottom of this...and if it ends up being a muffler thing, I will talk with the gurus at Sandale to see if they can come up with a way to help reduce this...I want more then anything to have snap, then top end.
Click to expand...
So Dan,would you say the bog sound would be worse on a larger 3" sandale vrs a 2.5 sandale for this delay,both with tune?
 
**sj** said:
I know what the problem is now...and will be seeing of theres a solution soon....
Click to expand...
OK come on steve,dont keep us in the dark to long,as winter is only 8 months away maybe!!lol..
 
I'm planning a Gaspie run early January where "snap" doesn't mean "crap". BUT i will have new studs & helix to practice with...
 
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