2000 sno pro rpm ???

[JIMMO]

I have a 2000 zr440 orange white primary spring updated weigts (-1gram). The secondary has a bmsxh with one shim and a green spring in 4th hole.+1 degree timing with 50/50 race gas. Good belt and tight deflection. My problem is it only runs up 8500 rpm. Shouldn't it run out at 8800 rpms? I removed 1 gram from the weights it helped a little. Any ideas? Thank You in advance.
JIMMO

[gspaulding]

What main jet? What type of racing? If sno-cross, should be approx 250-260 jet with 50/50 fuel. Also you don't have enough timing at +1 with 50/50 fuel. Your pipes cold with this setup, can't make heat for short course racing. Do you have stock timing curve? If so, and your snocrossing, put in 70/30 fuel (30% race) a 260 jet, timing at +2, secondary spring in 3rd hole, stock profile weight at 46.5 grams. Your cam is OK to start out with. Dont get too tight on belt deflection, doesn't load the motor as much and heat is down. This should get you started.

[gspaulding]

Forgot to mention, don't expect much more RPM in sno-cross situation. 85-86 is about right. Sometimes your slower if you try to make it rev. You just have to test.

[JIMMO]

First I would like to thank you for the help. I trail ride the sled. I also have had the "500" program installed in the CDI. It will not pull any more rpm on wide open lake runs. Always tops out at 8500-8550. If this is right I will leave it the way it is. If more rpm would help performance I would like to get it. Thank You Very Much

[gspaulding]

Try this for lake running. 50/50 fuel +2to3 timing, 270~280mj @ 0~10 above,1000ft or so elevation. You have too much cam for lake running. try 46.0 to 46.5 gram stock wieghts, 58-50 or 60-50 cam (start there) spring in the middle. Rpm should be 8650 to 8800 on the ice for long distance racing. This sled is touchy for primary weight, it's easy to get to heavy.