i've posted on this subject before and thought i had it whipped until this weekend. took the buggy out trail riding and it started to miss at mid to full throttle. i'll start from the begining.
when it did this a few months ago it turned out to be the coil. since then (within the last 2 months or so) i have replaced the coil, cdi and installed an iridium plug. i am running the same jet that i ran before which is a 150. i've been told that this size is too big in the CV carburetor but it has run fine and the plug is a light brown color which i assume is correct. it missed just slightly during full throttle the first day. the next morning it would fire right up and idle but miss pretty bad at mid to full throttle. i had an extra CDI with me so i put it in and it seemed to fix it but later that day it started again and is still missing only at higher rpm's and just once in a while. now my question. is there any other components than the CDI, coil or plug that would make it miss like that. since i've been running the 150 jet for a while and the plug color is o.k., i assume it's not that. could the float adjustment cause it? i've adjusted the valves and they seem fine. should i be running a performance coil and CDI? could a bad kill switch be the problem. i know when it comes to wiring there are so many variables and it seems to come and go without warning. it has me baffled. any ideas or suggestions i haven't tried???

my old 250 did that , it was the wires that go into the cdi plug, they were not seated good and would come loose. also check the bottom of the intake for cracks

thanks BIGE, i'll check all the connections and the intake. that sounds logical since it ran fine one minute and like poo-poo the next.

with that jet and a good plug color it sounds like its sucking air from somewher. whats your elevation

i'm in canton Ohio. elevation is 1060. I've taken the buggy to eastern ohio and southern ohio and it ran fine at both locations with the 150 jet. the plug is actually on the light side in color so that made me think that the jet wasn't too big or it would be dark from running rich. am i correct in thinking that?
i've checked the intake by spraying starting fluid around it while running and i notice no difference in RPM's. maybe i'll drop down to a 145 and see how it does. after i get the terminals tight on my CDI.

if the plug is a tan color then its fine, just havent heard a jet that big running a stock motor

I have one question for you since you had a hh250. with all the mods i've done, uni, bigger jet, gutted exhaust....i'm running the stock CDI and coil. will those mods make the stock ignition parts wear out any sooner or perform less? should i be running a performance CDI and race coil? i want to get the most out of my buggy but don't want to just start buying upgrades just for the sake of upgrading..if you know what i mean. if the performance CDI and coil will be better in the long run then i'll do it. i can't seem to find a coil with a long enough lead to reach the plug from under the plastic cover though. they are all too short. am i stuck mounting the aftermarket coil somewhere else?

I got the adjustable cdi in my hh250 It seems to run a bit cleaner at top end but thats about it.

Maybe your float is not right so you need the 150 jet just to suck enough fuel. I'm at 135 and I'm rich. Our petcock also likes to stop the fuel from time to time

the upgrades you have done wont make the cdi and coil wear out . the performance coil and cdi make the engine more efficient, they are not something you can feel in the seat of the pants.

the cdi will help it run cleaner thru out the rpm range, the coil will provide a hotter spark to burn more of the air fuel mixture.

I may be wrong, but I don't think there is a performance CDI for the CFMoto right now. There is an adjustable one, but I believe it is for the CN250. I just took that one out and put the stocker back in. It runs better with the stocker. I have a performance coil and it does fit under the plastic cover.