I am needing to re-jet my sport. I have FMF exhaust, K&N Filter and power reeds so far. I belive the stock jet is a 240. Any suggestions as to what size of jet I should use? Also I was told that driving it before rejetting could screw up the motor, it does backfire once in awhile, should I be concerned? Or just ride?

 

Yur way to lean!!! YOu'll burn a hole in your piston, and it can happen in less than 15 seconds!! With those mods I would start with a 280. Buy a 250, 260 and 270 also. DO the sparky test and more than likely it will be around a 260, but much better to start high than to low...

 

Thanks for the advice. I am new to modding atv's. What is the sparky test?

 

Sorry! Testing the mixture by checking the color of your spark plugs. If that is all the mods that you have done, then more than likely the only thing you will have to worry about is wide open throttle(WOT). YOu should put in the main jet that I specified before, starting rich. YOU MUST NOT DO THE FOLLOWING IF YOU ARE LEAN, so make sure that you are starting on the rich side. Warm up the motor, and take a pass down a long stretch, not to long, at WOT, then when you quikly come to a stop, kill the motor. Check the plug, and it should be coffee color, brown paper bag color... If it is black, yur rich, if it is white you are to lean, if it is sooty, you are way rich. You can further tune you carb by using the MUKUNI CARB tuning manual.pdf... The link to it is on the top of my gallery pictures. It is a long DownLOad, but well worth it, you will learn alot from it...

 

I ran a 260 jet in mine, with the pipe and K&N filter.......and the plug was fine. Make sure you keep doing a plug check.

 

ouch!,,,make sure to do a compression test before rejetting cauze that engine is wear out already,with pipe it take at least 270-280 main but that fmf is not very effective so maybe you're still ok.

 

The backfire I speak of just started occuring. I just finished putting on an oil injector block off and started it up to make sure that it didn't leak. I have not rode since putting the fmf gnarly pipe and turbine core II exhaust on. When the sport is rapped up a little it will, what sounds like a backfire, and shoot a little flame out the exhaust. The motor, as far as I can tell, is still a solid motor. I am just a little itchy about screwing it up. Thanks for all the help guys, and if you know of a good online site that will overnight the jets to me please let me know about it, I have searched stores but none of them say that they have jets for a 96 sport. Thanks again.

 

you would check as far the fmf pipe if it is a low end pipe or midrange
or even top end pipe naybe cayze,when you got a low end pipe,,,the exhaust chamber is efficient for low end torque and so on,,so it will take LEANER jetting on the bottom end (pilot jet and fuel screw)if you got a midrange pipe,,it will run a fat pilot jet and main while use pretty lean needle (midrange),and finally a top end pipe run on a fat pilot and and needle and run a pretty lean main jet then.
if you didn't rode the thing since the new exhaust mods and stuff,it
take a while for the mixture to be consistant and accurate,it take a lot
of heat then,so it is reacting to the new mods,so jetting will become very important.

 

I was running a 270 in mine with about the same setup.