How did you figure out your race to pump gas ratio? I am running. 13.6 heads on my 910 at the same elevation and am only using 1.5 gallons per full tank. Any more than that and my sled loses it's crisp throttle response and doesn't run right.
Have you ever reached Det on your sled? I would replace plugs like suggested and then start taking out some race fuel slowly. It's hard to pin point one thing it's could be a lot of little things adding up to the bog. Not proper clutching, your can, heads, timing, fuel ratio. Every little thing you do to your sled takes or adds something.
When tuning my 910, as much as I wanted a wam bam tune. I found out really fast it best to start as stock as possible and add one thing and tune. Add another thing then tune. I spent 8 hours one day just clutching my sled on one hill.
Your clutching alone will change how your sled runs drastically. I have vipec logs where all I did was change helix angle and it would change my afr reading a ton. If your patient with it though your gain a much broader appreciation for the motors and tuning. For instance when I know I am going to be putting a lot of load on sled from a certain snow condition. I can add more fuel through with my vipec to balance the extra load or I know if I am pulling to high a a/f ration and I didn't have my laptop to change a/f ratio I can change the helix to a smaller number and take some of the load off the motor. But then you gain some extra rpms on the top end and need to watch that. The tuning aspect can be a lot of fun if you stay patient with it and try not to jump the gun.
I would suggest starting over and listing every little think you can think of you have done to your sled. Motor mods, suspension mods, track, skis and then your riding style (chutes, trees, ditches, racing). One sled can be clutched, suspesion setup, a hundred different ways. But what works for me might not be what works for you. I have no desire to have the fastest sled on the hill. I want instant and crisp throttle response and a hard pulling in the bottom and mid range. That's where I do 99% of my riding, so that's how I have my sled clutched and setup for. People get on my sled all the time and say wow that is zippy but doesn't seem to go very fast. And I just smile and say I know
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Basically in a nut shell, it's more likely than not, more than one thing effecting how the sled is running. Especially from the things you have modified on your sled.
Best of luck there are some good guys on here with a lot of knowledge like will more than likely help you out. Just stay patient.
I believe tricity' website is Tricityperformance.net or you can google it.
