cant figure this out

[Mofo Racing]

I have a K&N and a sparks pipe. air box lid on.
problem is that I havent rejetted yet but it runs rich. real rich, the plug is black when I take it out. how is it doing this.:confused:

[ny300exrider]

you need to get a bigger main jet because with so much of an increase in air flow you need to up the jetting. pretty much all mods having to do with air flow will make your quad richer

[44oEX]

Originally posted by ny300exrider
you need to get a bigger main jet because with so much of an increase in air flow you need to up the jetting. pretty much all mods having to do with air flow will make your quad richer

ahh no it will make it leaner. more air no fuel.

Your air filter could be dirty. Did you put oil on it?? maybe you put too much. I would start with that.

[Pappy]

your plug may infact be black, but thats not a good way of determining rich at W.O.T. you will need to do some full throttle chops to see if your close. even then its only an educated guess.


is it missing or running poorly?

[ny300exrider]

Originally posted by 44oEX
ahh no it will make it leaner. more air no fuel.

Your air filter could be dirty. Did you put oil on it?? maybe you put too much. I would start with that.
ahh your right, my brain is in the gutter tonight. i have no clue why you would be running rich other than what 440 said check your air filter. if anything you should be pretty lean with stock jets and a pipe/filter.

[Pappy]

Originally posted by ny300exrider
if anything you should be pretty lean with stock jets and a pipe/filter.

most people have thier engines way to fat. ive run stock 400ex's with full systems and no lid with a 155 and a 425 with a fullsystem, k&n and lid with a 152. stock is a 148 so i can see where he would be running fine with his set up as long as the lid remains on. i would recommend a 152 for a margin of safety but if he isnt having problems he should be fine.

[jmpulse]

Originally posted by Mofo Racing
I have a K&N and a sparks pipe. air box lid on.
problem is that I havent rejetted yet but it runs rich. real rich, the plug is black when I take it out. how is it doing this.:confused:

For a quick test, you could run with the airbox lid off, and see if it leans it out some. You probally would also benifit from checking to see if there is any clogs in the exaust, or intake. Is the K&N over oiled? If so, you could be sucking a lot of oil into the motor, thus blacking the plug. Actually I would give this a big guess, K&N are a little touchy to oiling.

Hope that helps

[Mofo Racing]

oh my goodness the great pappy has answered on of my posts
I feel so special, o.k. enough hero worship.

I do put a thick coat of oil on the filter and I do need to rejet it, so I guess I cant complain. Another thing I failed to mention is that I think my battery is gone. If I leave it parked for 2 days I have to charge the battery before the starter will even turn over. but when its ran for a couple minutes, it starts fine.

oh well I guess you know you got it bad when you would rather run to the store and get a new spark plug for 7$ than spend 7$ and wait two weeks for jets.:D

[Pappy]

ummm...a weak battery could be taxing the electrical system causing the coil not to fire as hot at idle and low rpm's causing a weak burn:scary:

lol...thats a rare chance. get some good jetting runs and stop wasting money on $12 of gas to buy a $3 plug:devil:

[buster369]

r u sure its rich and not burnin oil?