no power in powder

[greenheadhunter32]

i have a 98 xcr 440 and every time i get off the "trail" into any kind of loose powder i loose all power and the engine bogs and studders. the carbs are clean and power valves are clean also. when im on a groomed trail or old tracks it seems to be fine.. any ideas?

[Moose-Hunter]

Although not the same sled, I had basically the same problem with my XLT. When I found myself in the deeper powder snow, it was all I could do to keep my forward momentum. After a bit of research, my problem ended up being low track speed. Not sled speed, but track speed. With my XLT being such a heavyweight, the minute I hit the powder, my track speed dropped to a point where the motor was out of the powerband and bogged the motor.

I cured this in two ways. First, I changed the gearing in the gear case. If memory serves, I dropped one tooth off the top sprocket. Next, I set up my clutch for "mountain" conditions. Higher engagement RPM and quicker shift out. I'm not sure if the gear change was necessary for powder, but id did help with my towing ability.

On a side note... Two years ago, I also did a long track conversion on this sled. I went from 121" (3/4" lug)to a 133.5" (1.5" lug). I wanted to go longer (136" or 144") but those conversions turned out to be cost prohibitive. It's still a pig, but it handles deep snow a whole lot better with a much improved trail ride.

Oh yeah... Another thing to check is your airbox. Make sure you're not ingesting snow "dust" into the motor.

Hope this helps...

[Knotwood]

We were out this weekend in about 20" of powder, the tracks sink in and the snow gets into the airbox, plugging the airflow, ingesting snow is not good for engines, and even blocked the airflow enough to foul out plugs. Took foam out, ice and snow packed, knocked loose and got going again.

[hanson]

greenheadhunter-

Is it just the engine that seams to be suffering or just your interpretation of speed/rpms, etc.

Snow ingestion occurs when in powder and hurts you. Install some screens for sure.

In loose snow, my sled even runs at a WAY higher RPM to keep a given speed because the track is just spinning but I don't ever experience a bogging or loss of power from the engine.

If it is in fact a bogging, I'd look at possible ways of ingesting snow and restricting airflow to cause the bog.

[MN Mike]

I had my M/C 800 out this weekend and it was bogging also. Put in 2 new plugs and we were good to go.

I think Moose Hunter might be on to something also but check your clutches and your belt too. If you clutches are sticky and can't backshift in the powder your in trouble, they work harder in powder than they do on the trail.

Belt length is important to, make sure that belt is fairly tight, it will stretch as it warms and if it is too long it throws your ratios all out of wack.

Mike

[greenheadhunter32]

thanks for the advice-

[beaverlakeman]

greenhead,

I had the exact same problem this weekend with my xc500.

worked fine on trails ect.. but once i hit some powder I lost ALOT of power, didnt have my powerband. Buddy behind me said when i gunned it in the powder, i barely left a pile of snow. My filters to the airbox did have snow in them but airbox was high and dry.

Brought it to the dealer yesterday and they took a look at it and he said i was only running on basically 1 to 1 1/2 carbs. There is a tube from the airbox to each carb that pressurizes the air per each carb. 1 of those tubes came off from the airbox. he pushed it back on and told me to take it for a ride and see if it was better.

All i can say is wow. felt like a total different machine. Even had way more power on hard snow.

I would definately check those 2 tubes and make sure they are both connected.

Clutching it will also help to keep your rpm's more in the power zone..

hope that helped, good luck