Clutching and fuel consumption

[number1kyster]

I have a 2018 RTX with 5,500 miles. It has been tuned with TD MS16 with the stock muffler, intake, and map sensor since 1,500 miles.

I have never been one to pay much attention to fuel consumption. However, next season we are planning some longer saddlebag trips where range is important.

I started my season with 24/50 gearing. Riding tight twisty trails was netting 11-12mpg taking it easy. 2 weeks ago I switched to 22/41 and I’m up to 13-14mpg.

My sled spins 9,000-9,200 depending on conditions. Would a heavier clutch weight net better mileage? Or am I getting what everyone else is getting?

Here are my specs.
Stock 35 helix
Stock secondary wrapped to 3/3
Stock weights
XS825
Yamaha Blu/Brwn/Blue primary spring.
22/41 gearing

My wife’s 900T running the same trails at the same speeds is getting 19-20mpg.

 

[Turboflash]

Technically, yes. If you're always up in that RPM range, IMO I would slow it down a couple hundred.

 

[Turboflash]

Important question though is what is RPM at speed you're riding? Depending on the rest of your setup, adding clutch weight might not change it that much. Key would be to have it run slower at the RPM you ride at allot.

 

[justinator]

The stock weights are a flat profile and in my experience usually net better fuel mileage.........not as responsive as a lighter more aggressive weight but usually cruise at a lower rpm. The 35/39 helix typically cruises at a lower rpm then 35 but thats not saying its better setup by any means. More weight or more helix will lower your cruise rpms a bit but you may lose a few hundred rpm on the big end.

 

[number1kyster]

The stock weights are a flat profile and in my experience usually net better fuel mileage.........not as responsive as a lighter more aggressive weight but usually cruise at a lower rpm. The 35/39 helix typically cruises at a lower rpm then 35 but thats not saying its better setup by any means. More weight or more helix will lower your cruise rpms a bit but you may lose a few hundred rpm on the big end.

That makes some sense. My 2018 and my dad’s stock 2017 were always close at the pump but his 2022 with the 35/39 seems to be a fair amount better.

 

[STAIN]

I am getting 13.5-14.5 mpg with 24-50 gearing, stock tune.
My friend running a T-cat with a 240ss tune and same gearing is getting the exact same mpg.
I think you may need to get your clutch's to upshift quicker.......
I do have a 35-39 on my shelf you could try.
I also have a complete set up from G-force ( Gagne Lessard) that is completely different and upshifts quickly. I am not sure we have enough snow left to test that completely.

 

[number1kyster]

I am getting 13.5-14.5 mpg with 24-50 gearing, stock tune.
My friend running a T-cat with a 240ss tune and same gearing is getting the exact same mpg.
I think you may need to get your clutch's to upshift quicker.......
I do have a 35-39 on my shelf you could try.
I also have a complete set up from G-force ( Gagne Lessard) that is completely different and upshifts quickly. I am not sure we have enough snow left to test that completely.

I have a trip booked in Northern Maine is 2 weeks. What other changes should be made with a 35/39 helix? Different spring as well?

I may be interested in the G-force setup, but I don’t want to make huge changes before a big trip. Backyard testing will be coming to a close after this week.

 

[Motorhead]

I have a 2018 RTX with 5,500 miles. It has been tuned with TD MS16 with the stock muffler, intake, and map sensor since 1,500 miles.

I have never been one to pay much attention to fuel consumption. However, next season we are planning some longer saddlebag trips where range is important.

I started my season with 24/50 gearing. Riding tight twisty trails was netting 11-12mpg taking it easy. 2 weeks ago I switched to 22/41 and I’m up to 13-14mpg.

My sled spins 9,000-9,200 depending on conditions. Would a heavier clutch weight net better mileage? Or am I getting what everyone else is getting?

Here are my specs.
Stock 35 helix
Stock secondary wrapped to 3/3
Stock weights
XS825
Yamaha Blu/Brwn/Blue primary spring.
22/41 gearing

My wife’s 900T running the same trails at the same speeds is getting 19-20mpg.

The gearing change gave you a couple more mpg, so that worked in trying to better your mpg.
Next would be to try getting your WOT down a bit, and I have tried a couple things to accomplish that, more tip weight, or as mentioned the 35/39 reverse helix. That helix is know to take a bit out of rpms out of both, mid and top end!

But as you already know, snow conditions can take that all away or make it better. Hard trails or icy trails are the best, trails with 2-3 inches of snow, or soft conditions Take away.

Either way love that 19 - 20 on your wife's sled. We bought my wife a sled at the end of last season after years of getting out of sledding because of back issues. We bought a 2012 Vector in immaculate shape, and it also kills me by 3-4 mpg!!

 

[Upstater57]

Part of MPG is track tightness. If I am not running the lakes ( high speed ), I tend to leave my track a little loose. That gets me 13 - 13.5 MPG. Tight track gets me about 11.5 MPG stock tcat gears. Used to get 14 - 15 MPG with 21/38's. Lots of variables that include conditions. The numbers I just shared are for hard pack trails.

 

[KnappAttack]

Heavy primary weights will always get better fuel mileage. That is why you want to clutch to the big tunes.