I have found these methods to work pretty good for me. Some may have other ways of running their plug chops and setting fuel mixtures but this is what works for me.
PLUG CHOP HOW TO
Before you run the plug chop you will need to first make sure the fuel mixture and or low end throttle are correct the air filter is clean and oiled. You're going to need a few new spark plugs too . 3 or 4 plugs are cheaper than 200 for a rebuild kit. Now grab your plug wrench a rag and go find you at least an 1/8th - 1/4 mile straight that's not illegal. lol You want to ride your quad around for 10 min or so get it nice and hot. (the trip to your riding spot will help warm it up). I usually run down to the opposite end of my work area so when I make my chop run I can stop where my tools are. OK here we go... remove the old plug install the new one. Start your engine and take off you want to run w/o throttle through each gear up to 4th, STAY OFF THE LIMITER IN ALL GEARS!!! once you hit 4th hold it for about 8-10 sec stay in the throttle and hit the red run/stop switch on the bars IMMEDIATELY and SIMULTANEOUSLY pull the clutch and let off the throttle stop your quad and then remove the plug. install your old plug and head back to your shop/shed/house. It helps if you have a vice. you want to lock that new plug in the vice then take a hack saw or die grinder and cut the threads away from the plug exposing the whole porcelain. Now here's the misconception of plug readings. you would think the whole porcelain would need to have that cardboard brown color. . Wrong. you want to see an ring of that color close to the base of the porcelain. If that ring is too light your main jet is too small. of it's too dark it's too big. If you ran this test with the air box lid on and the ring was dark, remove the lid and run it again on the other new plug. Jetting is NEVER cut and dry and NEVER is bike "A" jetted exactly like bike "B" we can only offer a starting point based on past experiences. Your bike is different. Have patients this will take you a while allot of trial and error and new spark plugs. Also keep in mind a plug chop on a 90 degree day will yield a different result than a 70 degree day. Jetting is in fact seasonal, most do not do it but it is.
SETTING THE AIR/FUEL MIXTURE
To set the air/fuel mixture screw you need to have a warm engine. while the engine is at idle, you want to increase the idle by about 100-200 rpms (which isn't much). Now . . . while counting turns SLOWLY turn the screw in by 1/2 turn increments and allow 3 or 4 seconds in between for the engine to stabilize as best it can. Once you get the screw turned in to lightly seated record the turns for reference only. SLOWLY back that screw back out in the same method as you did turning it in. Please allow that few seconds for the engine to acclimate to your changes. As your turning the screw out notice that the engine RPMs are also increasing. DON'T FORGET to count the turns!!!! Once you get to the highest RPMs turn it a little extra just to be sure; then turn it back. Let the engine stabilize and then turn it back IN an additional 1/4 turn.
PLUG CHOP HOW TO
Before you run the plug chop you will need to first make sure the fuel mixture and or low end throttle are correct the air filter is clean and oiled. You're going to need a few new spark plugs too . 3 or 4 plugs are cheaper than 200 for a rebuild kit. Now grab your plug wrench a rag and go find you at least an 1/8th - 1/4 mile straight that's not illegal. lol You want to ride your quad around for 10 min or so get it nice and hot. (the trip to your riding spot will help warm it up). I usually run down to the opposite end of my work area so when I make my chop run I can stop where my tools are. OK here we go... remove the old plug install the new one. Start your engine and take off you want to run w/o throttle through each gear up to 4th, STAY OFF THE LIMITER IN ALL GEARS!!! once you hit 4th hold it for about 8-10 sec stay in the throttle and hit the red run/stop switch on the bars IMMEDIATELY and SIMULTANEOUSLY pull the clutch and let off the throttle stop your quad and then remove the plug. install your old plug and head back to your shop/shed/house. It helps if you have a vice. you want to lock that new plug in the vice then take a hack saw or die grinder and cut the threads away from the plug exposing the whole porcelain. Now here's the misconception of plug readings. you would think the whole porcelain would need to have that cardboard brown color. . Wrong. you want to see an ring of that color close to the base of the porcelain. If that ring is too light your main jet is too small. of it's too dark it's too big. If you ran this test with the air box lid on and the ring was dark, remove the lid and run it again on the other new plug. Jetting is NEVER cut and dry and NEVER is bike "A" jetted exactly like bike "B" we can only offer a starting point based on past experiences. Your bike is different. Have patients this will take you a while allot of trial and error and new spark plugs. Also keep in mind a plug chop on a 90 degree day will yield a different result than a 70 degree day. Jetting is in fact seasonal, most do not do it but it is.
SETTING THE AIR/FUEL MIXTURE
To set the air/fuel mixture screw you need to have a warm engine. while the engine is at idle, you want to increase the idle by about 100-200 rpms (which isn't much). Now . . . while counting turns SLOWLY turn the screw in by 1/2 turn increments and allow 3 or 4 seconds in between for the engine to stabilize as best it can. Once you get the screw turned in to lightly seated record the turns for reference only. SLOWLY back that screw back out in the same method as you did turning it in. Please allow that few seconds for the engine to acclimate to your changes. As your turning the screw out notice that the engine RPMs are also increasing. DON'T FORGET to count the turns!!!! Once you get to the highest RPMs turn it a little extra just to be sure; then turn it back. Let the engine stabilize and then turn it back IN an additional 1/4 turn.