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I know this should be in the XP section but I want you guys with XM's to hear my experience with clutching & gearing for low elevation.
I did a lot of poking around on here before bringing my summit back from the mountains this winter. There is very little info out there on how to set these sleds up properly for low elevation. A lot of people seem to be clutching and thats it, with the attitude that if your off trail riding that the stock gearing is good. However if your clutching to make up for all the extra horsepower you gain at sea level than shouldn't you gear accordingly? I started off by going to 19.4 gram pins and that dealt with over revving. I am on clicker 1, I should likely be using 20-22 gram pins so I can adjust clickers properly howver its bang on 7900 on clicker 1. Before touching gearing it honestly felt OK for off trail riding, and topped out around 75 MPH on trail. I needed more top speed for a longer trail ride I had planned several weeks ago so decided gearing was in order. Went with the same gears as a renegade BCX 800 (23-45).
By doing this I assumed I would be losing all my low end grunt for top end speed. WRONG. Low end grunt was much much better and top speed increased by 15-20 MPH. Its as if there is too much track spin with the stock gears.
All of a sudden after doing the gearing I have a persistent hesitation at 7000 RPM. It is sometimes OK at slower speeds when playing in deep snow and will let me run WOT. But if on trail or even in deep snow trying to run hard, like 60MPH in deep snow or 80 MPH on trail, right when I reach 6800-7000 it cuts out like im hitting the rev limiter. It basically acted like a governor, limiting my speed to 60. Was very annoying during the 215 Mile ride I did last weekend.
I started reading on here about the hesitation and how it could be voltage issues, or needs a re-flash or is just some computer glitch that may never go away. However it was weird that this hesitation only occurred after gearing. I didn't want to go back to stock gearing as it is the wrong set up for low elevation and makes me push the sled much harder to keep up on rides. I read on one thread, that a guy had issues with his aftermarket can at lower elevations but not at high elevation. And my sled has an MBRP trail can that it came with when bought used. So today I swapped the can out for stock and went for a ride. 2 minutes go by, and this is usually when the hesitation occurs. I ran 85 MPH for 4-5 minutes straight no hesitation. Then went off trail in deep snow and held it wide open for as long as possible and no hesitation!!
So somehow the taller gears in combination with the MBRP can must raise the EGT's just enough that the computer limits itself is what I have concluded.
I now have an MBRP can up for sale... The heavy stocker will have to do.
Hope this may help other who have summits and are running them at low elevation. Sled is a 2012 Summit X 154. I swapped the 2.5" track out for a 2.25". Runs 90 ish MPH on trail and in deep snow has all the low end grunt you need and can pick the skis up and hold them up for longer than it could with the stock lower gearing.
I did a lot of poking around on here before bringing my summit back from the mountains this winter. There is very little info out there on how to set these sleds up properly for low elevation. A lot of people seem to be clutching and thats it, with the attitude that if your off trail riding that the stock gearing is good. However if your clutching to make up for all the extra horsepower you gain at sea level than shouldn't you gear accordingly? I started off by going to 19.4 gram pins and that dealt with over revving. I am on clicker 1, I should likely be using 20-22 gram pins so I can adjust clickers properly howver its bang on 7900 on clicker 1. Before touching gearing it honestly felt OK for off trail riding, and topped out around 75 MPH on trail. I needed more top speed for a longer trail ride I had planned several weeks ago so decided gearing was in order. Went with the same gears as a renegade BCX 800 (23-45).
By doing this I assumed I would be losing all my low end grunt for top end speed. WRONG. Low end grunt was much much better and top speed increased by 15-20 MPH. Its as if there is too much track spin with the stock gears.
All of a sudden after doing the gearing I have a persistent hesitation at 7000 RPM. It is sometimes OK at slower speeds when playing in deep snow and will let me run WOT. But if on trail or even in deep snow trying to run hard, like 60MPH in deep snow or 80 MPH on trail, right when I reach 6800-7000 it cuts out like im hitting the rev limiter. It basically acted like a governor, limiting my speed to 60. Was very annoying during the 215 Mile ride I did last weekend.
I started reading on here about the hesitation and how it could be voltage issues, or needs a re-flash or is just some computer glitch that may never go away. However it was weird that this hesitation only occurred after gearing. I didn't want to go back to stock gearing as it is the wrong set up for low elevation and makes me push the sled much harder to keep up on rides. I read on one thread, that a guy had issues with his aftermarket can at lower elevations but not at high elevation. And my sled has an MBRP trail can that it came with when bought used. So today I swapped the can out for stock and went for a ride. 2 minutes go by, and this is usually when the hesitation occurs. I ran 85 MPH for 4-5 minutes straight no hesitation. Then went off trail in deep snow and held it wide open for as long as possible and no hesitation!!
So somehow the taller gears in combination with the MBRP can must raise the EGT's just enough that the computer limits itself is what I have concluded.
I now have an MBRP can up for sale... The heavy stocker will have to do.
Hope this may help other who have summits and are running them at low elevation. Sled is a 2012 Summit X 154. I swapped the 2.5" track out for a 2.25". Runs 90 ish MPH on trail and in deep snow has all the low end grunt you need and can pick the skis up and hold them up for longer than it could with the stock lower gearing.
