Hello everybody. Might have seen te other thread, but this I a 99 sportsman 500 that I have essentially rebuilt the whole qad, besides the tranny. With the engine broken in I pull the plug and the ground strap is white, the base rig has black on about 1/2 of it. The porcalin is pretty white with not much soot on it. It has run a whole tank of premium through it and the plug was new at the start of the tank. Main jet should be a 155 that came with the moose kit that I put in. It pulls great to 20, and then at wot it seems to lack a little, probably the effects of running lean. I am wondering if runing normal 87 octane will help this issue as I have read, or if I need to reject for a 160 or something. Can't figure out how to get a picture of the plug on here, sorry!

Thanks for the help felas!

 

Running higher rated octane than recommended is just a waste of money along with on a lot of machines won't run as well. Found this out on a number of machines.Lower compression engines can't burn the fuel properly. Higher octane rating such as 93/95 is required for atvs like the Outlaw that have a higher compression engine and need the higher octane to help keep the engine from detonation and run to cooler and maximize horse power.Try a a tank of 87 or 89 oxygenated as the manual says and see how it runs.

 

http://forums.atvconnection.com/pict...ictureid=45123

this is running 87 octane now, elevation 800' and its winter so about 15-25 degrees outside.
i had it between half and wide open throttle during the ride before i pulled the plug and tool pics.
the pics might look like there is dark soot but it is actually bleach white.
The whole bike has been apart and all air system checked for cracks. I also just sprayed carb cleaner as it was running and no change in idle. again using a moose carb rebuild kit. any suggestions?
thanks for any help!!!!

 

Cold temps will make them run lean also.152.5/155 is a generalized main jet setting for sea level to about 3000 feet,but not carved in stone. If you're scared just get a 160 and 165 main and see if you can get a tan to medium tan reading on the electrode. You can also raise the slide needle a notch or two to richen up the mid range.As long as your sure you have no air leaks causing this.

 

well i have been running a 165 main and the needle up one notch, might move it up agian. plug was looking better and have run half a tank so far going to pull the plug again today.
thanks OPT!

 

Just check the plug for a medium tan color and you should be fine.Come spring/summer you may need to drop the slide needle if it starts blubbering on you on take off or mid range. Just depends on the temperature. Hotter it gets,the richer it will run.