A few questions

[sprtrx300ex]

ok I was wondering if it is possible to run a K&N filter without rejetting. If so do i need to turn the mixture screw really lean? Also, I know the spark plug is supposed to be brown. To get it brown i have to have between rich and lean right. I can't seem to get it brown only grey.

THANKS!

[RiPPiNiTuP7]

The only way where its a possibility to not rejet is if you leave the lid on....but even then, you still might have to rejet.

[sprtrx300ex]

I planned on keeping the lid on.

[Texan32]

DO NOT put alot of faith in a plug check. We hae talked about this here before. With all the different addatives they are putting in gasoline these days, the color on the plug really can't be trusted!

[ChadEXer]

Thats one good thing about running VP C series race gas!!! You can always tell how your bike is running!!! Yellow is lean,,,green is way to lean,,,grey is just right,,,dark grey or brown is too rich!!!!

[Doibugu2]

My motor is all stock, and I don't have a slip on. When I installed the K&N, I did not reget. I also left my lid on. I did eventually rejet, and I actually went down in size of my main jet. I was actually running a little fat. You should be okay though.

[sprtrx300ex]

do i need to turn the mixture screw leaner to take care of the richness, or can that ruin my motor.

[Texan32]

ok, we need to review fundamentals.
Stock motor with nothing changed= correct jetting
motor with K&N filter, no jet change and lid on=SLIGHTLY LEAN
motor with K&N, no jet change and no lid=LEAN
motor with K&N, pipe and no jet change=REALLY LEAN
...the only way you are going to have a RICH problem is if you rejet to a overly large jet! If ANYTHING (if you don't rejet) you should richen up you fuel mixture screw setting on the bottom of ther carb.

[sprtrx300ex]

I was running my K&N filter with outerwears precharger, looked at the plug and it was black. Everything else is stock. I took off the K&N, and put stock filter back on. I look at the plug now and it is white. I turned the screw to the left to make it richer. Then it was black. Ever since i've tried to get it close to brown but I can't its either white or black.
I thought
black= rich
white=lean

[Texan32]

ok, i'm kinda stumped. I have never heard of a K&N causing a richer mixture. You are correct about the plug.

[sprtrx300ex]

ok. I put the K&N back on, rode for 20min, and checked the plug. It looks like this:

[Doibugu2]

Texan,

I heard everyone before saying that Honda sets the quad up to run lean. Maybe that has changed? I am only at 800 elev. When I did reget I noticed it run a little nicer. I know what your saying from your 1st post, but does Honda put the same jets in no matter where the quad is sold? I mean does honda put different jets in for colorado dealers vs. chicago dealers? That is a huge diff in elevation. That may explain why I was running rich.

[sprtrx300ex]

ok. I put the K&N back on, rode for 20min, and checked the plug. It looks like this:

[spliffy]

WAY LEAN!! :eek:

[Texan32]

Doi....
I think you might have taken my post a little too literal. The main point i was trying to make is that when it comes from the factory, its "supposed" to be good to go. If you don't touch it, you should never have to adjust it. See what i'm getting at?! i do understand what you are trying to say though. I don't live in a high elevation area. So, i can't say weither or not they send different jetting options. If you live in a higher elevation, you would think that maybe the dealer would rejet the carb. But then again, maybe not. Running rich really won't do harm. It will just cause the plug to foul up quicker...and bug a little in extreeme cases. I'm not going to claim to be an expert by ANY means, so please, take my advise only for what its worth...an average guy's experiences.

sprtrx
it looks to me that it is running a little lean. Maybe its just the pic, but it def. doesn't look rich....like i said...thats just what the pic seems to say

edit...also check the gap....could be the angle of the pic, but it seems a little small

[sprtrx300ex]

It is a NGK plug. I believe they are pre-gapped.

[Jay300ex]

I am taking an engine course in school and the first unit we did was spark plugs. so heres a couple of things, when you buy plugs pre gaped its only to a a few thousands of the spec, so you should still check it. when you examine the plug colors you look at the ceramic insulator not the ground electrode or center electrode, though they can tell since the ceramic is white anyway, if your running lean its hard to tell sometimes, and as it was said before the additives in the gas might make the colors vary. that plug pic does look a bit lean, and lean is bad you would end up burning the piston and rings, such and such but im sure you all know that stuff =)


jay

[sprtrx300ex]

I put the stock filter back on. I can't seem to get the plug to change colors! It stays the same as it is in the picture. I tried riching it up a lot, no change. I tried leaning it up, still no change. I tried a new plug same color. WHY! Just to make sure,it your on the side of the engine where the spark plug is, Then turning the mixture screw left is rich and right is lean correct?

[Texan32]

yes, right is lean, left is rich. This just goes to show you that you can't trust the plug. Here's what i would do. Put you in a new plug. Put on your K&N. Leave the lid on (thats how you wanted to run it right?). Set the mixture screw to the factory setting. Go for a ride. Nail the throttle. Once its open, let off. If it pops on de-acceleration, you need to richen up the mixture. If it deosn't, i would let it alone and go have fun riding!:D

[sprtrx300ex]

Thanks for all of your help. Ok i don't know where the stock setting is and i dont have a tool that can get it seated. Does anybody have a pic of the factory position?

[Jekyl_22]

I'm positive that my 400ex has to be way out of tune... I have bored it out to 440cc, 11:1 compression, K&N Filter, and I run it without the airbox lid. Its probably running way lean? Obviously I don't know much about jetting... some help???:confused:

[sprtrx300ex]

can anyone describe the factory setting for a 300ex? I live in Virgiana so it might be off.

[Doibugu2]

Tex,

I get what your saying. I wasn't questioning what you were saying, but actually just talking out load.

[sprtrx300ex]

ok,will it make a popping noise when it is rich or only when it is lean? I revved it up at an idle and let off, and it popped once or twice, but doesn't do it every time I rev it.