Engine runing like chit please help

[Sick0]

My engine went from running strong to running like crap. Last week the motor went from running strong to sputtering. Its only does it with I'm half to full throttle. It doesn't matter what RPM i'm in. It runs fine when the cold but then starts to chop up again. I don't think its the engine its due to the fact its problem reacts to throttle postion instead of Rpms. I've check the spark plug and I get diffrent readings. but nothing that bad. I'm starting to thing its the cdi box or something. These are the I have checked.

I change the oil, cleaned the air filter, tryed to rejet, put diffrent (stock) carb on with jetting I've used before that ran good, installed a diffrent pipe, changed spark plug, check fuel line, change fuel brands. What do you think it could be,

[Sick0]

I adjust them all the time. sorry I did adjust them too.

[Sick0]

Is it possible to have a crack intake boot would that do that.

[cals400ex]

yep, check the intake boot to make sure its on tight and doesn't have any cracks.

[Sick0]

I'm pretty sure I figure it out. It looks like I blown thw head gasket. Probly after installing the 440 kit the headstud didn't hold.

[400ex#18]

choon, choon, choon...You never have your quad running...After you left the pits the other day, i got 2 flats, and my clutch gasket blew, None of us are having good luck...Well i hope you have your quad running for the next race, or have one to run in the next race!!! :blah:

[Sick0]

Well I torn down the whole engine and every thing looks good but the head gasket. I worry the stud had tore out or the head or piston was f-up. I should be there ready.

I think i blow gasket in the 4stroke race. I felt something go wrong in the motor in that race. The quad power was diffrent the rest of the day and has been runn worst ever day I ran after wards.

[400ex#18]

well that is good news i guess...At least you will be at the next race, and get to race jolly finally this year.:blah: Well i had an extra gasket for the clutch and i am putting it in in the morning and pos. riding if your not working which you prolly will be, stop down at the pitts or give me a call first to see if i'm going?

[Sick0]

I'm working but i thinks its going to rain all day. I will probly out of work early tomarrow but I will be working on the quad.

[400ex#18]

Ok...well maybe i'll stop by. If it is raining out hard, then i prolly won't go, but i need the practice, so who knows...where will you be working on it? At kenney's, or your house?

[Sick0]

I have a new place. My grandmother letting use her garage. Which sweet. I can work on it any time I want, and it like the first real place to work on the 4wheeler. its better than the steet or my bed room.

[400ex#18]

LoL...that is cool though...If you want to give me a call so i know where it is and maybe i can learn more chit, by seeing how you do it. Just give me a call sometime tomorrow if you want, and if i am not around leave one...But i have soccer at 3- about 6

[Sick0]

Pm your number I lose it again.

Soccer player:)