Clutching help? Not holding RPM

[JonezyBones]

Went riding last weekend and noticed that my sled was only getting 7600 RPM when in loose snow. Checked it on the trail and it was spot on 8150 and would hold.

So yesterday I checked the primary and installed a new spring. (SLP Green pink 160-320.) I also cleaned the power valves and they were a bit gummy but no holes in the bellows. Also changed plugs and made sure the connections were clean.

So went riding today and sled ran great up until we got to the powder. Low and behold same thing... this time 7400 in loose and 8000 on trail.(Higher elevation)

I only have a little over 600 miles on my 12 pro 163 and last winter I had changed over to my spare because my first belt had some cords ripped out. (I assumed from snow coming through the foot well and my belt slipping a lot.) Changed the first belt when I had about 400 miles on the sled so I don't think my belt is the issue. Also have the oiler turned up about 3 turns and the sled has no change when I switch the ethanol plug around. (Running 91 non ethanol.)

Its coming down to maybe injectors? Or I got some issues in the secondary. The problem got way worse when I ran the sled in deep snow for a while and it seemed to really get heat saturated. I saw rpm's as low as 7100. I haven't been inside one of these team clutches yet so if anybody has some ideas for things to look for it would be greatly appreciated.

Sorry for the long post but I wanted to give as much info as possible.

Thanks!

Edit:

Also sled ran great last year at the end of the year. I was normally pulling 8150 all around.

 

[Sheetmetalfab]

Check your secondary

I had a cracked roller in mine. I chased clutching setups for awhile. Then it worked good most of last year.
Had issues holding rpm late last year.
First ride this year dropped a cylinder skirt.
Sent to indydan.

 

[BB454]

Check compression. If it's Ok then look at the driven. If you have a dual angle helix, switch to the flater final angle although I think it's a single angle. That will let it hold RPM better. Delrin washers will help as well.

 

[Dootimes2]

What kind of temps are you seeing on both clutches. Any black marks on primary or other performance issues. If one clutch is hotter than the other start there.

 

[rabbit hunter]

I have the same issue with my 13 800. I would pull 8200 on the trail and in the pow it would fluctuate between 7300-7900. I pulled .8 grams from each weight and switched it to 91, same thing with higher rpm on the trail. Third night I pulled the secondary and noticed that I was only using about half of my helix. I pulled the black and purple spring and put the stock black back in. It seemed better. I think maybe I got a bad spring. I will get it taken apart tonight and let you know what I find. Also I did notice my primary had a dark ring of belt rubber and my secondary is clean. 200 miles on the sled.

 

[JonezyBones]

I have the same issue with my 13 800. I would pull 8200 on the trail and in the pow it would fluctuate between 7300-7900. I pulled .8 grams from each weight and switched it to 91, same thing with higher rpm on the trail. Third night I pulled the secondary and noticed that I was only using about half of my helix. I pulled the black and purple spring and put the stock black back in. It seemed better. I think maybe I got a bad spring. I will get it taken apart tonight and let you know what I find. Also I did notice my primary had a dark ring of belt rubber and my secondary is clean. 200 miles on the sled.

Yeah my situation sounds almost identical. Had a dark ring around primary and secondary was clean. Yesterday I went out and sled was acting the same so I changed back to my other spare belt and guess what, she ran great! Maybe I just got a bad belt? only about 200-300 miles on it. Wish I could get a warrantied belt.

 

[BB454]

Scrub that belt with dish soap and a scotch brite. May have something slippery on it. Old racers trick.

 

[winter brew]

I would start by replacing both clutch springs and making sure both clutches are in perfect condition (bushing wear?) and clean.
What arm weight? What altitude?
That much RPM drop almost sounds exhaust valve related...clutching is typically very gradual as things wear.