question on setup for stock gearing

[sheetwright]

Last weekend I was finally able to try some of the power adders I put on the Sidewinder, and have some questions. I need to know if the top speed I'm seeing is related to conditions, setup, or that I'm a fat a$$?
*Area riding was the trail 3 near Houghton with long straights, About 3" of pack on the trail
* Setup is Turbo Dynamics power trail tune, Stock gearing, Thunder products clutching (Both orange springs) and 911 kit, with Turbo dynamics trail quiet muffler
* Clutch was setup by Greg Goodwin with Lonnies assistance. (guess they are long time friends)
* Using Gates belt supplied from Thunder products
* Max RPM I was seeing 8800RPM
* Thunder products is set at 3-1
* Outside temps ranged from 22-34 degrees Fahrenheit (not cold or ideal)
* Max speed seen on the dream O'meter was 112-114MPH depending on the trail
* My weight is 250lbs no gear
* Track is the stock 137", 1-1/4" ripsaw on the 2017 LTX-LE

I know the stock gearing should get me around 125mph. I figured that the temps that weekend, and my weight would make the top end suffer some, but didn't think 11-13MPH. Would of guessed more like 5-6MPH. I know I need to adjust my weight to gain that another 100-200rpm. Do you suggest adjusting weight or going to 3-2 on the clutch? Also am I expecting too much for the conditions, and weight? Don't get me wrong this thing punished the 850's, and 800's Polaris's in our group. Perfect trail systems near Houghton and phoenix for the Sidewinder. Thoughts on this?
FYI I am not a top MPH guy looking to go to the 22 tooth. I just want to get the most out of the gearing I have. Love the low end grunt

 

[**sj**]

its all in the clutching (most likely) why not contact the clutch tuner....just saying....and no to the 22

 

[Doc Harley]

Groomed heavy snow + your weight. = 110mph+

Hard pack and/or ice 115-120mph. Guessing.

I wouldn't think of changing gear.

 

[Big_Phil]

My theory is the stock gearing is only good to 112 mph at 1:1 shift ratio. Anything after that you're into overdrive. My sled will pull like a freight train till about 110, and then the pull slows considerably.

You lose clutch efficiency when you get deep into over drive, and it will prob only pull that 125mph in perfect conditions. Glare ice or close to it, plowed ice roads are usually pretty fast too.

 

[Fleecer]

Last winter I ran stock gearing with TD Eco Trail and hit 126mph speedo many times in good conditions. At 114mph, I think the last thing you need is to gear up.

IMO.....I think your issue is in the clutching and/or your belt. Other Gents can correct me if I'm wrong here, but I think the GATES belts are same length as the Yamaha 8DN belt. I tested Yamaha 8DN belt and lost 100 rpm and 4 mph top end.

First thing I would try is an 8jp belt and make sure deflection is up to spec!!!

 

[**sj**]

Thanks for saying it fleecer

 

[74Nitro]

Last weekend I was finally able to try some of the power adders I put on the Sidewinder, and have some questions. I need to know if the top speed I'm seeing is related to conditions, setup, or that I'm a fat a$$?
*Area riding was the trail 3 near Houghton with long straights, About 3" of pack on the trail
* Setup is Turbo Dynamics power trail tune, Stock gearing, Thunder products clutching (Both orange springs) and 911 kit, with Turbo dynamics trail quiet muffler
* Clutch was setup by Greg Goodwin with Lonnies assistance. (guess they are long time friends)
* Using Gates belt supplied from Thunder products
* Max RPM I was seeing 8800RPM
* Thunder products is set at 3-1
* Outside temps ranged from 22-34 degrees Fahrenheit (not cold or ideal)
* Max speed seen on the dream O'meter was 112-114MPH depending on the trail
* My weight is 250lbs no gear
* Track is the stock 137", 1-1/4" ripsaw on the 2017 LTX-LE

I know the stock gearing should get me around 125mph. I figured that the temps that weekend, and my weight would make the top end suffer some, but didn't think 11-13MPH. Would of guessed more like 5-6MPH. I know I need to adjust my weight to gain that another 100-200rpm. Do you suggest adjusting weight or going to 3-2 on the clutch? Also am I expecting too much for the conditions, and weight? Don't get me wrong this thing punished the 850's, and 800's Polaris's in our group. Perfect trail systems near Houghton and phoenix for the Sidewinder. Thoughts on this?
FYI I am not a top MPH guy looking to go to the 22 tooth. I just want to get the most out of the gearing I have. Love the low end grunt

Here is my setup and numbers from an 18 XTX, 1.6 Cobra which has the 8 tooth 3 inch drivers. I'm 160 lbs.
PT tune, SQ muffler, Dalton DTYA's, empty, 8DN belt and stock gearing.
I was able to achieve 126mph many times this past winter, on the trail.
I also observed the RPM's on one of these pulls and here's what happened. The sled was holding 8900 RPM until the sled got to 119 mph, then the RPM's started to climb. Obviously my clutches were fully shifted at that speed. When the speedo showed 126 MPH, the tach was reading 9400
As I understand it, the 137's use 9 tooth 2.86 drivers which should give more top speed.
Also, I'm not sure if my speedo is accurate, I have not compared it to GPS

 

[**sj**]

It's possible you are gulping air... Might be interesting to see what the GPS number is comparatively...

You have 8 tooth x 3 pitch which equals 24 in and the 9 tooth x 2.86 pitch equals 25.74 ... Obviously the 9 is more efficient... But don't discount the 160 cheeseburgers

 

[74Nitro]

It's possible you are gulping air... Might be interesting to see what the GPS number is comparatively...

You have 8 tooth x 3 pitch which equals 24 in and the 9 tooth x 2.86 pitch equals 25.74 ... Obviously the 9 is more efficient... But don't discount the 160 cheeseburgers

Ya, I did the math too. Maybe the calibration in the ECU is the same setting from the factory irregardless of which of those 2 drivers are on.

 

[Srxspec]

@sheetwright 8800 rpm with 21/41 gearing & 9 tooth 2.86 pitch drivers is good for 109.xx mph. Conditions must be VERY GOOD generally to pull into overdrive. If you were running the 8DN equivalent Gates belt you were also giving up 4-5 mph with that belt as well.

@74Nitro the ECU has different speedo calibrations for the different driver sizes.

 

[74Nitro]

@sheetwright 8800 rpm with 21/41 gearing & 9 tooth 2.86 pitch drivers is good for 109.xx mph. Conditions must be VERY GOOD generally to pull into overdrive. If you were running the 8DN equivalent Gates belt you were also giving up 4-5 mph with that belt as well.

@74Nitro the ECU has different speedo calibrations for the different driver sizes.

Thanks, good to know.

 

[**sj**]

Allen what's your primary spring rates 30/90 kg? measured at?

 

[Srxspec]

Allen what's your primary spring rates 30/90 kg? measured at?

Same heights as stock Yamaha springs.

 

[Big_Phil]

Here is my setup and numbers from an 18 XTX, 1.6 Cobra which has the 8 tooth 3 inch drivers. I'm 160 lbs.
PT tune, SQ muffler, Dalton DTYA's, empty, 8DN belt and stock gearing.
I was able to achieve 126mph many times this past winter, on the trail.
I also observed the RPM's on one of these pulls and here's what happened. The sled was holding 8900 RPM until the sled got to 119 mph, then the RPM's started to climb. Obviously my clutches were fully shifted at that speed. When the speedo showed 126 MPH, the tach was reading 9400
As I understand it, the 137's use 9 tooth 2.86 drivers which should give more top speed.
Also, I'm not sure if my speedo is accurate, I have not compared it to GPS

Stock gearing? If so your speedo is way off. Your max speed at 1:1 shift would be about 105mph, take away a few mph for the 8dn belt. 116ish with full overdrive, but again, minues 4-5 mph for the 8dn.

 

[74Nitro]

Stock gearing? If so your speedo is way off. Your max speed at 1:1 shift would be about 105mph, take away a few mph for the 8dn belt. 116ish with full overdrive, but again, minues 4-5 mph for the 8dn.

Like I said, I question the accuracy of the speedo on my sled. I plan on purchasing some GPS equipment for next season.