My 99 sport 400 seems to be using gas really fast and i wasnt sure if this is common for 2 strokes or if something was wrong. Im mixing my gas at 40:1 using 93 octane. Any input would be appreciated. thanks

 

why are you using 93 octange? is the engine been modded and have high compression? if not your wasting your money on the high octang. check the plug and see if its black in color. maybe the float is set wrong or the main jet is too big. also make sure the air filter isnt plugged. just a few things to check.

 

If its anything but stock I highly recommend 93 octane. The 400 two strokes are very touchy. I also agree by starting with the plug. The plug tells the story on whats going on in the motor.

 

I would bet the plug is ok if it is running good.The 400L loves gas at least every one I have owned did.

 

I just replaced the plug last week so thats not it. When I bought it the guy said it had a jet kit but thats all he could tell me. He bought it with the kit already installed.

 

All two-strokes use, and waste, a lot of gas. All that smoke isn't just oil. Maybe it needs re-jetting closer to stock.

Also, higher octane fuel actually has less heat energy, and is harder to ignite. If your engine <u>needs</u> it, then you need it to avoid pre-ignition. But if the engine doesn't need it, <u>there's no performance benefit</u>, and actually it will, in theory, reduce your power and mileage because of it's lower heat energy, and the fact that the ignition system will have a harder time igniting it. Higher octane fuel burns more slowly, meaning that you can add more timing and not get preignition. But if it's tuned for the faster burning lower octane fuel, then the ignition will occur later than optimal with high octane and won't burn as completely, and should then yield worse mileage. But what do I know? I'm just a bear on a scooter.

 

Thanks. Ill try using a lower octane fuel. Do you know where i can pick up a manual for this thing I can't seem to find one anywhere. Kinda off topic but will a starter from a 1995 scrambler 400 4x4 work for my sport.

 

Go to polaris.com. and search for owner's manual, and parts manual. I found a '98 owner's and '99 parts manual. You need to have an account and sign in. These links are working for me.
http://pi54.com/corp/manuals/Owners/9914659r02.pdf
http://pi54.com/corp/manuals/Parts/9914953.pdf

 

not all 2 strokes waste gas as our 250 trail blazer was extremely good on gas. w/ a jet kit in it would be harder for sure. how did the plug look when you changed it?

 

on the starter all 2stroke polaris starters are the same