polaris pro 5 800

[tomerik]

The engine goes only up to 7000 rpm. it is a pro 5 ves 800 2005 mod,slp twin pipes, stingers, slp high octane head and v-force 3. I'm running avgass 100LL mixed with ordinary gas. The belt is 307*44. The gearing is 23/43. The primary has 10-64 weights and a black green spring. The secondary has a66.46.46/62.46.46 helix and a red gray spring. My jetting is 450. The needle is at the last clip. the number on the needle says Rn5-57. im driving from 0 to 3700 feet. My feeling is that it is to fat in the midle. Could it be the reson to my problem? Change to a thicker needle? I have checked the ves and both opens like they should. Could the problem be the outside temperature. Last day I did a test. I lifted the snowmobiles rearend up and gave full trotle. The engine stopped a fraction of a second at 7000 rpm before it vent up to 8200 rpm, which it did every time. Does anyone have an idea what causes the problem?

 

[sled_guy]

I don't know what those needles are. If you're running the fatter needles from like the '04/05 motors then I'm going to say your jetting is fat. If you're running the leaner needles then it isn't. If the midrange is fat, unless it's WAY fat, it isn't going to kill 1200rpm off the top end.

Check your temp sensor and TPS to see if they are good and if the TPS is set right.

sled_guy

 

[markis24]

I would "read" your plugs to get a baseline established. Make sure it's not something stupid like your fuel line getting pinched either.

 

[tomerik]

I don't know what those needles are. If you're running the fatter needles from like the '04/05 motors then I'm going to say your jetting is fat. If you're running the leaner needles then it isn't. If the midrange is fat, unless it's WAY fat, it isn't going to kill 1200rpm off the top end.

Check your temp sensor and TPS to see if they are good and if the TPS is set right.

sled_guy

Thanks. I will check the TPS at the dealer tomorrow. The temp sensor is not in use.Why i dont know. My needle is nr J8-9DGN06-57. Which is orginal for the 600 HO. So it's probaby not the needles.

 

[sled_guy]

If the temp sensor is not in use then you better make sure it is bypassed with the right resistor or the CDI has it programmed out. Simply unplugging the sensor puts it in failure mode which will retard the timing and take HP out of the motor.

sled_guy

 

[tomerik]

Thanks. I will check the TPS at the dealer tomorrow. The temp sensor is not in use.Why i dont know. My needle is nr J8-9DGN06-57. Which is orginal for the 600 HO. So it's probaby not the needles.

Finally. The problem is solved. One of the cylinders had a slightly damage. and the secondary spring was way to soft. The engine is now running straight up to 8100 rpm. Halleluja.