need help on 300ex running

[jeepin21]

just rebuild my motor with wesico 11:1 piston, web cam with hardened rockers and hd valve springs also have k&n with lid removed and a dynajet kit with a fmf exhaust and a ricks hotshot cdi. put it all together and runs good for around 10 to 15 minutes then seems like (but isnt) hitting the rev limiter when you try to excelerate it will keep geeting worse and worse till it will to it in neutral and you can hold it wide open and wont go seems like above 3000rpm and just ba ba ba just like if it was bouncing off the rev limiter. i have tryed what seems to be everything wide assortment of jets and every clip on the needle, tryed different coils and cdi boxes, tryed running it with reserve on and with gas cap off. i have recheched timing and it is spot on and my valves are adjusted correctly. dont know what to do your suggestions would be a big help.

[jeepin21]

forgot to put if you let it cool down 15 to 20 min will run like a top again till it heats up and starts acting up.

[Sjorge450R]

eh, check the wires going into the right clutch cover. You may have them switched, but it should be doing it all the time. Just try that first.

[2muchquad]

I have seen the stator cause these conditiojns.Try and swap out with a known good one.Make sure your coil is good as well.Electrical problems can cause all kinds of havoc:(

[exman]

check the comnnection from the main wireharness to the front harness,,,gey connector,,just above coil,,on frame rail,,,alot of times when you open it up..look at the hot wire terminal...(red wire),,they are known to burn over time,,and sometimes the give you good contac and sometimes they don't

[jeepin21]

thanks for the tips guys i only have time to work on it on the weekend so i will try the suggestions out then. thanks again

[alexmx22]

if none of that works check the main jet in your carb

[dork]

sounds like a stator or coil.

[jeepin21]

Thanks for all the tips i switched the wires going into the right clutch cover and as you thought yes it made it run bad all the time. It does seem like it was that same sputtering but only when it gets hot. not cold.
Also looked at the gray connector and there was no corrosion or dirt in it.
I have also tryed a wide assortment of main jets
Last thing i guess i have to try is a new stator. Does anyone else think it is a stator ? Not that i dont trust you but its a little pricey and a pain to change but if everyone thinks it that then it is worth a shot. let me know if anyone has any other suggestions. THANKS AGAIN

[jeepin21]

I still need some help

[smr]

Sounds to me more like the CDI. Usually stator or coil will shut the quad down and they are very intermitten.

Swope the cdi with somebody and see if that helps...(it must be one off a 300ex as the 250x is different)

[jeepin21]

i have a ricks hot shot cdi box on it and sweapped it back out with my stock one. still does the same thing

[jeepin21]

any other help would be great

[Lonestar_R]

Sounds like maybe your floating the valves...but since you HD valve springs that shouldn't happen....I could see it with stock valve springs though

[spent21]

hey, i was wondering if you ever found out what was wrong with your bike. i have a 250x that i just built the engine in, and it's doing the same exact thing! the thing about it is i ran the bike to warm it up before draining the oil for the rebuild, and it ran fine! i have run the resistance tests detailed in the service manual, but that is just for the stator, excitor, and the wiring. i'm beginning to believe that it is the cdi.

[dork]

i rebuilt a 350x that did the same thing, ran good before it was parked and after the rebuild it would hit a 'rev limiter' at about 6k. turned out to be the cdi. what year is your 250x?

[spent21]

it is a '92. i asked the same question in a different thread with only 1 response. that guy cleaned every connection and he said it ran fine afterwards. i had to pull the engine back down because of a leak, so i haven't had a chance to test it since cleaning my connections. this is beginning to become a pain in the arse.