I had to go up on the pilot when I jetted cause when you went down hills it would lug and want to(and did) stall out...If youve ever done Jetting you can kinda tell when its Idling sometimes(air screw) and in my case when tackling hills,you can tell on your pilot.... even at stock I think the idle was off just a Tad.....~~ RNGMSTR ~~ I was wondering how you liked your Vortex CDI?Been thinking this will be the next investment, was it worth the $$? Thanks Tina
Okay pretty much a good way to find out if you need to rejet the pilot is after accellerating while deccellerating if there is any type of popping of any sort then you pretty much need to rejet the pilot. People please do not slaughter me if I am wrong but just kindly correct me as I am only a stupid little 19 year old. Hope this helps. I pretty much jacked the info from the Mikuni site
1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ---- the exhaust then pops or backfires.
Difference in power well yes and no. If your pilot jet is'nt right you will foul your plug out sooner (If it's a rich spot). The longer it idles, the blacker the plug becomes. It doe'nt matter if you ride it hard, it does'nt all burn off. Just adds to the black, you need not change your pilot setting. Not unless you have your air screw is more than 3 1/2 turns out. And or only 1 1/2 turn out,then it's time to change the pilot. Up or down on the pilot depends on the alt,temp,ect you live at. Sh#t this could be a long post getting into jetting. But remember that this is a CV carb and it's easy (yea right) to turn the idle screw. To ajust for the different temps, if it's popping on deccellerating turn it in or out, see what works on your mach. But please remember that you can ajust only one circuit at a time. Ajust the pilot 1st than the neddle than the main. If you need more help just ask. I'm out of time. Thanks
I do not have my air screw 3.5 turns out and I required a larger pilot size. Jetting is weird, you could take numerous quads with the same mods and what work perfectly on one isn't always going to work on the rest, they might all end up wanting slightly different set ups, so someone telling you what jet sizes to run will only give you a decent starting point, you may or maynot have to go up or down from that starting point. It get extremly aggrivating sometimes, but stick with it until you get it right and you will be a-lot happier with your machine. By the way, when you are changing the jets, don't look at the floats the wrong way, it seems that with this wonderful carb that it loves to adjust itself a little every now and then just to piss you off.
RNGMSTR ......boy you got thatright!! Jetting is a real beeitch!!!And its dif. from quad to quad Im finding..Had the jetting almost dialed in but was stumped, so I took it in finally after be so fusterated, found it was the pilot and then the other settings were only off by a smidge along with flaot bowl adj. The float helped a buch and going up on the pilot too.....My 400ex was the easiest to dial in and my 300ex and 2 stroke min for my Daugher was the hardest....
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