Dragy Times?

[rev them up]

I'm kind of a bit disappointed with my numbers. I feel like my sled launches pretty well for being a 129 and just on hard pack. It's of course still way faster than any of my friends 2 strokes. But it just doesn't pull much past the 1/8th mile or 1000ft it seems. I have to get the chaincase open and see what gears are in it, I'm feeling like I have to be running out of gear. I say this because it seems to run the same traps/speeds through 1000ft on the 250 or 275 tunes (I've never tried 285)

Mods:

• TD 250/275/285 tunes
• TD super quiet 2.5 exhaust
• TD Cold air intake
• Dalton Adjustable Clutch Weights

View attachment 169082

Those seem low. What rpm are you turning? What primary/secondary spring and how much weight are you swinging? Stock belt or other.

 

[1Kurgan1]

Those seem low. What rpm are you turning? What primary/secondary spring and how much weight are you swinging? Stock belt or other.

I thought so too, I messaged TD and they just pointed me at gearing. I have the Dalton Adjustable weights (These ones). The rpm's usually are in the 8800-8900 range.

I'm honestly not sure on the weight, I just have adjusted the weights when swapping between 250/275 to make sure that it doesn't go over 9k. As far as the rest of the clutching, to my knowledge it would be stock cat. And the belt I am running is the Ultimax XS 827.

 

[DMCTurbo]

I thought so too, I messaged TD and they just pointed me at gearing. I have the Dalton Adjustable weights (These ones). The rpm's usually are in the 8800-8900 range.

I'm honestly not sure on the weight, I just have adjusted the weights when swapping between 250/275 to make sure that it doesn't go over 9k. As far as the rest of the clutching, to my knowledge it would be stock cat. And the belt I am running is the Ultimax XS 827.

You probably are running stock 24 50 gearing. Gear it up.

 

[Turboflash]

RPM is good. Speed looks exactly like 24/50 runs. As DMCTurbo says, gear it up, especially since you are running a decent tune.

 

[1Kurgan1]

You probably are running stock 24 50 gearing. Gear it up.

Yeah, that probably is it, I would think it has to be.

The only weird part is, when I got it the guy said he put in 24/50 gears (despite that being stock). And I have the original gears/chain in a box that came with the sled. He seemed like a meticulous guy (president of snowmobile club in the UP), so maybe just replaced stock for stock being afraid of top gear bushing wear.

I was thinking 21/41, I know 22/41 is popular as well.

 

[snowdust]

That is odd about the gears. I guess you'll see when you open it up. I posted a couple runs last year between the gears that you might be interested in. Don't worry about the overall speeds as much as this was on a narrow rail bed where I couldn't get good starts. You can see a decent difference between the gearing though. With better starts the lower gearing may have been faster longer, but you can see the taller gearing takes over.

Data Log Sample - Feedback

The throttle is actually wide open the entire time. It fluctuates between 99 and 100 for some reason @yamamarc - Why is your IAT reading so low? It was -20*c that morning. I run the gap ram air also not sure if that makes a big difference or not? I haven't seen any higher then 30*celcuis(300...

ty4stroke.com

 

[1Kurgan1]

That is odd about the gears. I guess you'll see when you open it up. I posted a couple runs last year between the gears that you might be interested in. Don't worry about the overall speeds as much as this was on a narrow rail bed where I couldn't get good starts. You can see a decent difference between the gearing though. With better starts the lower gearing may have been faster longer, but you can see the taller gearing takes over.

Data Log Sample - Feedback

The throttle is actually wide open the entire time. It fluctuates between 99 and 100 for some reason @yamamarc - Why is your IAT reading so low? It was -20*c that morning. I run the gap ram air also not sure if that makes a big difference or not? I haven't seen any higher then 30*celcuis(300...

ty4stroke.com

You are my hero with the 22/41 to 24/50 direct comparison, and our times/traps being pretty close. That makes me feel much better, it looks like I must have 24/50 in the sled then. I've been so busy working on getting the plow truck ready for winter as we are already getting hit with snow. I'll have to find time to make it into the chaincase and order what I need.

How has the 22/41 been on belts? I was thinking 21/41 to cut down on lugging it during trail riding, but those 22/41 results do look great.

 

[74Nitro]

What were the conditions you were running on? I did 11.04 at 114.57 with 24/48 on firm trail.
With stock muffler and 260HP

 

[Fords4life]

I have found that the stock team primary likes the 24/50 gearing for slow speeds, under say 25mph in twisties caught behind tourists, the bearing used for auto belt deflection causes a higher starting ratio, which i have seen causes belt slip on the primary down low on sheves, had this problem with the 22/41 gearing on my 2018 zr9000 129"...just some food 4 thought!

 

[snowdust]

No blown belts for me in ~5k miles. (with a variety of gearing over that time) I am running Yamaha clutches so something to consider as @Fords4life mentioned above. I ran my XS825 belt for just over 2k miles last time and just put a new one on this year.

 

[kinger]

This was a couple years ago. Sled blew up for 2nd time after this run. Only capture the 0-60 and a horrible launch. This is BTX 153 1.75”

 

[justinator]

I thought so too, I messaged TD and they just pointed me at gearing. I have the Dalton Adjustable weights (These ones). The rpm's usually are in the 8800-8900 range.

I'm honestly not sure on the weight, I just have adjusted the weights when swapping between 250/275 to make sure that it doesn't go over 9k. As far as the rest of the clutching, to my knowledge it would be stock cat. And the belt I am running is the Ultimax XS 827.

Dont worry about it going over 9000, I bet your times would improve at 9000-9200. Actually I know they would on those tunes. The fastest guy doesnt spin 88-8900 and has more hrs testing then he’d probably care to admit.

 

[rev them up]

Here is mine, only got one run in.
2018 ltx, ms17,ggb muffler(since gone to 3inch stock mod but have not had the condition to try, added 3.5grams with the new muffler) dalton clutching, 1.5 storm track. Just rolled into throttle as you can tell with horrible 60ft times..lol. groomed snow trail.

 

[rev them up]

Here is my nytro xtx, full hurricane exhaust, k&n filters, 1.75 lug, dalton clutching parts, run were in a grain feild with less then idea condition, hauls the mail for what it is, 106.9 gps groomed trail.

 

[74Nitro]

I'm at 11.05/115 in the 1/4 on packed trail with stock reverse helix and Yamaha weights.
Stock muffler, max spool 260hp setting.
Next year would like to try 41/37 with the GForce weights I use now.