I am all out of idea's on the 440. I put my .50 lug speed track on it with 144 1 inch studs for drag racing. Just to putz around with it since we don't have snow. The whole sled is sucked down and hooks like its on rails. I have a 19/43 gear ratio which is supposed to be a 80 mph gear @8500 rpm's in it. The sled turned 8500 RPM's with the stuck clutching and track. S-51 weights, almond and red primary spring, 70/44/46 helix and the red/blue spring. After putting the other track on and sucking it down the best I could get it to turn with was 8300 RPM's with the stuck clutching. I went down to 48.5 gram weights and lost rpm, then I tried a stiffer primary spring and still didn't gain much. I ended up with the almond and red spring and S-49 weights and was able to get about 8400 RPM.

The sled pulls like a rocket for about the 1/8th then does absolutley nothing. You can tell the motor wants to pull but it just won't. The best it seemed to pull in the middle on top was when I had 48.5 gram weights and the blue/lght blue primary spring. It only was turning 8200 RPM and it wasn't pulling all that great. Seemed to really hurt it off the line to. It almost feels like its running out of gear and I know it shouldn't be but it feels like it. I would pull the rev 440 through the first 1/8th and the last quarter of the track he would make up about 4 lengths and go by me about 20 mph faster it seemed. I'm thinking maybe I went the wrong way on weights and I need to try something heavier to pull the motor harder. It feels like the motor is free wheeling and not pulling anymore.

any chance you have a fuel problem, really lean or rich? that will cause the same thing your telling us.whats the EGT at 1/8 and 1/4

I know its not jetting, It was rich with 290 mains in it and I took it down to 250's and it still did the same thing. The 250's was the right jet for my elevation and temp on the jetting chart. The only factor I can see is the 110 octane gas, I know that stuff doesn't like cold weather but if Polaris recommends it then it must be ok. I'm pretty sure its something with clutching. I think I am going to try some stiffer weights tonight and see what it does.

I also forgot to mention that I put the secondary from the 440 on my Pro X 600 trying to see if something was messed up in the secondary. The secondary from the 440 really woke it up. Before the 600 felt like a pouch on the bottom compared to the 440. With that secondary on there it felt like a rocket and you could feel the differnce.

Maybe with the suspension sucked down, you have excessive track tension, which will hurt your speed badly. Why not try it with the suspension set at normal ride height first? Your track must also have 1.5 " slack with 10 lb. weight 16" ahead of rear idler wheel. Also, are you running 660', or longer? If longer than 660', you are running out of gear, I would say. Maybe the weight of the studs is dragging it down, and you need to go to a shallower helix to compensate.

Trust me the track is plenty loose. I got it to the point where its about to start racheting. I wouldn't do this for ice ovals or lemans but for drag racing we loosend it up a lot. It was 660ft but it seems to do it no matter, even with the stock track in it. Its just like it doesn't pull past 330ft. Its rock solid on the bottom but won't pull up top. I did try a shallower helix but all it seemed to do was kill my bottom end. Granted it was a 58-42-46 helix so it had the same finishing angle.

Unfortunatley I didn't get to try the heavier weights tonight because we were working on the modified. Trying to get ready for next season and stuff. Hopefully tomorrow night I will have some time to try some differnt stuff. I also think I am going to go up on the top gear to maybe a 21 and give it a shot.