jetting questions [Archive] - ATV Riders Forum

leviathan2244

05-04-2010, 04:25 AM

I have a 440 ex with stage 1 hot cam K&N air filter no lid on air box stright out no baffle muffler & running a 165 main & stock 3rd clip position on needle with pretty good luck so far. I still have stock slow, pilot jet and need to up it to a 45 I think so I can remove the choke. Even without removeing the choke I still need to up the pilot. Umm I think I backed out my screw and extra turn as well to 4&3/4 I think. If you still have the stock jet you need to get it up ASAP or you might melt the piston. Dont run it at all till you do but if you do run it dont run it hard till you run a plug check to see where your at. If you need to know how to do a plug check its easy. Just put in a brand new plug (a new plug is highly recommended) if a new one is not available clean the one you have with a wire wheele on a bench grinder or some kind of wire brush and get the whole end of it that goes in the head, very clean thats the end youll be looking at. Have the bike already warm and some place you can start it and immediately take a hard, full throttle, quick ride without having to idle it any more than possable b4 installing the new or cleaned plug. Start it and as soon as it fires up take off full throttle through at least 4th gear, 5th if possable, but if you have to turn to come back, pull the clutch so the engin dosent hold back and come back wide f****n open (wfo) lol and at the top of your last gear pull the clutch and kill the motor, Thats what your really shooting for is being shure to pull the clutch and kill the motor when its at the top of 4th or 5th gear so you can see how much gas the jet is letting in at that most critical throttle position. Anyway cost in to your parking spot and let it cool if you need to just dont get burned and pull the plug and look at the color of the end of it. What you want to see is a brown type color. White is lean and black is rich so you want it to be right in the middle. Just always remember to go a little richer (darker) insted of lighter. I hope that helped but if you have any questions just e-mail me leviothan2000@yahoo.com or post back here and Ill keep an eye out for ya. But id say since I typed this whole big thing you probly already knew how to run a plug check lol. Good luck and let me know your results.