Okay, there's no such thing as a stupid question, just stupid people....anyway..... Will anything be affected on my minimotard KX85 if I remove the airbox and put an individual pod filter on it? I've seen it on others but wasn't sure if jetting needs to be adjusted for the change. Thanks
You will probably be hurting the performance. I have been contemplating airboxes, ramair and other intake issues and have decided that the very least you want from an inlet system is ambiant atmoshperic pressure at the carb mouth which means a large airbox and a big filter. Ray
Anything is possible, but the hassle probably won't be worth it. I have seen at least 1 YZ/YSR hybrid that would not run correctly without the air box to carb "boot" connected. Intake tract length plays a major role in a 2 strokes tuning. You will probably be able to jet around the problem you would create by taking the air box off, but I doubt you will see much gain in performance. All that being said, a real tuner/builder (not a hack like me) will probably respond to this and explain why I don't know what I'm talking about... tom
It sounds like it's not worth it. I was hoping to shave a little weight and plus I've seen it on some of the serious racer's bikes. Thanks for the help guys.
It's not a problem Putting a K&N on my KX80 Motard didn't effect jetting, BUT, that's because I was running WITHOUT an airbox with a larger carb than stock. This stuff has to be designed using modeling software if you want it to actually work. There are optimum carb sizes for the bike and as has already been said, intake tract length plays a role, though it's not nearly as important on a case reed motor than it was on the old piston port stuff. All this stuff can be computer modeled now days, what my tuner did. He has a killer program, not sure what it is, but it models the whole motor flow from carb intake to exhaust stinger and changing lengths and volumes and timing and such to stuff in the motor can be done in the cyber world without touching port tool to metal and the program will spit out a power curve for the model. Neat. Helps, too, when doing mods, to use a flow bench to varify results. He will soon have a flow bench to play with, woo hoo! The stock motor has a conservatively sized carb and port timing because a MXer needs grunt as well as horsepower. Tuning the bike for more top end will see you adding a larger carb for better flow at the expense of grunt. I won't tell what carb I'm using to my potential competition , but it's bigger than stock. Port work also effected jetting. Before the port work was done, I could get 45 minutes + out of a tank of gas. The other day at NPR we ran a last minute put together mini "endurance" of 30 minutes length. It was really just for track time, fun time since RPM had some extra time available and were paying track rent anyway before the big bike race, so we got together and did the 30 minute thing. I took the checkers and half a lap later, after only 30 minutes, I ran out of gas! I've gone from a 180 Mikuni average main to a 230 with the ports and it made that much difference. It did give me a bit more power to play with in sprints, but I can't run an endurance without an extended range tank of some kind, now. If you are keeping the stock carb, I'd keep the airbox. It isn't hurting your performance and it'll filter out the rocks, rain, whatever and help your motor last longer. If you go to a bigger carb, fit a K&N to keep the rocks out. Jack
Thanks Jack. The motor is completely stock for now When I decide to replace the pipe, silencer, and whatever porting I'll consider it then.
