dry carbon fouled plug..

[TheX1992]

my plug is DRY carbon fouled. the book says its like a bad spark or something like to much gas ive had a long day i cant remember exactly. but what i do know is i have gone up AND down with the jets, fixed my boot and cdi wire so its got a clean connection for spark (tested and have plenty), and have pulled enough hair out to fill a 55 gallon drum. how do i fix this?

[cals400ex]

when you look at a plug color, i believe you want to look at the white piece under the electrode. with the fuel additive these days, plug readings are not always the best. if your plug is black and fouling, i bet your rich. however, this may not be on the mainjet, it may be on the pilot or needle. let us know the factory size pilot and main jet and then let us know what you have in there now and we may be able to help.

[TheX1992]

im running b-32 gas. stock main jet size is a 125. i went to a 134 in steps of 2, no difference each way. i put in a 158 main too and that was way to much. stock needle position is in the middle, but i went 1 down. im not sure about the pilot, but i havnt changed it. i have .20 12:1 weisco piston, port n polish head, stock cam, valves, and a supercrap exhaust, k&n filter

[cals400ex]

your best bet would probally get a new spark plug and start over. i would bet you would need around a 130 to 134 main jet. it probally wouldn't hurt to go up one size one the pilot either. the third or fourth position should be correct with the needle. so how did the bike run when you were changing main jets?? also, what octane fuel is that your running?

[TheX1992]

118 octane



it runs like crap

idling it goes up and down
midrange its really doggy
WOT it bogs up and down
changing jets or idle screw made NO difference on how it ran at all

[cals400ex]

118 octane, holy crap!!! thats quite a bit. if changing jets made no difference on how the bike ran at all, then there must be a problem elsewhere. i am assuming your carb is clean and the throttle isn't sticking? also, make sure your throttle cable isn't too tight so your throttle isn't always staying partially open. besides that, i am stumped. sorry if i wasn't much help.

[TheX1992]

its either 110 (watered down turbo blue) or b-32 118....same price, no water lol. carb is fine...accelerator pump is pretty bad though. im just going to get another carb. what are the advantages to a 400ex carb? i cant seem to convince my dad to let me get one. i told him it will bolt right up with a 350x airboot.

[cals400ex]

i would say that with a 400ex's carb you will get more up top but may lose some grunt down low since its bigger. i actually don't have a clue if it fits or not.

[murray]

Get rid of the leaded fuel !! I went through a ton of plugs before I realized that it was the lead additive that was giving me grief... Just use some quality 94 from Shell or 93 from Amoco... Remember, you are running a low compression, air-cooled, low power motor... You won't notice a difference !

[twisted threads]

Originally posted by murray
Get rid of the leaded fuel !! I went through a ton of plugs before I realized that it was the lead additive that was giving me grief... Just use some quality 94 from Shell or 93 from Amoco... Remember, you are running a low compression, air-cooled, low power motor... You won't notice a difference !

I agree! I think its your fuel.

[TheX1992]

can i run 93 octane with a 12:1 piston??? i was told 11:1 is pushing it with premium (93)