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yx 150 daytona cuts out when hot

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burnzy

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Discussion starter · #1 ·
Hi, my engine seems to run fine in the first 10 mins but after that, at about 3/4 throttle in first gear and sometimes second gear it will cut out for half a second abruptly then come back on, give me a shock as every time it does it the bike wants to wheelie. Tried changing plugs and played with every needle setting, plug chop seems to be fine and other than the cut outs which are random the bike runs very well.

Ideas? So far I'm thinking it's either the CDI or coil.
 
#2 ·
Its been my experience that your getting rich when its hot.. Try droping the main a size or to and see if that helps.. But engines get richer as they get hotter... If it was the coil or cdi it would most likely stay off till the bike cooled down.. :cool:
 
Discussion starter · #4 ·
thanks, I thought it was getting too rich but moving the needle full downwards has no effect, and it's not so much a bog but an outright cut, like no spark. hate random things lik e this..
 
#5 ·
I might be reaching here...



Float level.



If it's only in first and occassionally in 2nd I doubt it's the CDI or coil. I would think it would happen in every gear.



On my bikes, 1st gear 3/4 throttle the bike vibrates like crazy. Lots of harmonics from the motor because it's not under a load usually in 1st gear at 3/4 throttle unless your hill climbing or something. In 3rd or 4th you dont get near the vibration and harmonics.



So if the float level is low and your getting a ton of vibration the fuel could be just going everywhere in the bowl and your carb could be sucking air/starving for a second.



I said I was reaching but if you think about it, it may be a possibility.
 
#7 ·
thats weird my buddy's truck just started doing that 2 days ago too! I thought it was the tranny at first but it shifts perfect just it cuts in and out its weird now im thinking either the spark is cutting in and out of a cylinder or more or the fuel filter is pooched



I dunno on a mini id say it has to be either electrical or fuel related too
 
Discussion starter · #8 ·
might be possible that it's fuel trackstar, or maybe the vibrations are shaking something electrical loose intermittently. it doesn't backfire or anything though. Wierd. Might go around and redo all the connections before getting new cdi/coil. I have checked the float and cleaned the jets.



chasetheface: yx 150 daytona is the new yx150 with the daytona style casing. runs same bore/stroke as the lifan 150s
 
#9 ·
Burnzy the needle wont have an effect if the main is to big. you said it runs good untill it gets hot.. You probably dont have to choke it to start it. And if I put to big of a main in my bike it starts to cut in and out like a rev limiter in the top end of the rev range.. Its doing it only when its HOT is a good clue its jetting related.. Try droping your main if you have say a 120 go to a 115 or a 110 it would probably get better there isnt anything clogging the carb...
 
#10 ·
A while ago my YX160 was doing something similar, I tried adjusting the carb, checked pretty much everything I could.. I decided to swap out the coil to see if it would help, sure enough that's what it was.. I guess they go bad from time to time.. They're pretty cheap to swap out, it's worth a try..
 
#11 ·
i have a yx150 and i went through the same thing...the china stators are junk in those bikes.. i went through 2 different inner rotor kits on it and a china stator with a flywheel and it still burnt the stator out.. i put the honda stator with the flywheel setup on it.works like a charm now and have been riding it for about 4 months now.
 
#12 ·
I have a YX150 also that is doing something similar. My son races it. The bike runs fine for the first couple laps, then it starts to miss, or sputter at high rpm's. It gets worse as the moto goes on. The rich jetting idea is curious to me since the plug is definitely not lean. I have taken the factory inner rotor out and replaced it with a standard outer rotor. It seems to calm the motor down and make it much easier to ride especially for my 12 yr old.
 
#14 ·
just had a similar problem with a pitster lxr with a z155 that had YX ignition matted to it.. the flywheel magnets broke off and the inner ring was coming off..

bike started real hard, and over all the jumps and stutter bumps the motor would cut out (miss)... got complete z155 ignition and when removing YX system i found the flywheel to be broken apart...



hope this helps, and you either have a YX 150 OR a 150 Daytona.. they are very different engines...
 
#16 ·
I re-jetted and replaced the plug my YX150 today. Still an awful sputter. I'm gonna try electronics next.



One question though. Is it possible to connect a coil wrong? Will it run if it's connected incorrectly?
 
#19 ·
I'm running a 100 main(down from a 105), and 25 pilot. At first I thought it was only doing it when it warmed up, but the other day it seemed to do it as soon as I started it up. It ran ok in the lower rpms, but when the throttle was wide open it began to sputter and miss badly. I leaned the jetting out first (it was a bit rich anyway) then a new plug and it still missed, then changed the coil. So far problem solved.
 
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