Following Son

[ZKDX]

Went riding yesterday with son (XR50), and everytime i would follow behind him for any length of time i would foul a plug. We were riding trails. Is this just because i'm riding a 2-smoke, or am i not got my jetting right yet.-----87 kdx 200,FMF Torque Reeds, stock exhaust, 300main, 30jet, BR9ES. After I fouled two plugs I put in a BR8ES, I didn't foul any more plugs, but i also tried to keep my wrist twisted!

 

[G. Gearloose]

The 9 plug was definately a liability. However I question the 'R' plug, I don't think an 'R' plug was spec'd until at least '95, on US bikes.

 

[atc3434`]

Yeah, I would second the plug being at fault... not quite hot enough. Had a few rides in years past on a 220 with my riding partner and his wife on the TTR125. We had to really putt when we took her out, and the KDX never let a plug go on me. In fact, its still got the original plug in it from the factory... and its a 2000. BR8ES I believe.

 

[ZKDX]

my manual called for a B9ES for u.s. models and a BR9ES for all others. But when i went to local parts store, and asked for the B9---i was looked at like an idiot, and so like an idiot i took the BR9----by the way, we i pulled the fouled plugs they were not so much black fouled like i was expecting, but just wet, they were a little black, but mostly just wet.

 

[G. Gearloose]

thought of something else to check, that era KDX has a bad habbit of the glued-in magneto magnets loosing adhsion, an easy thing to verify.

 

[ZKDX]

dumb question #?: how do i easily verify that?

 

[HOTRODKY428]

GET A CHAMPION,I HAVE BEEN RUNNING THE SAME PLUG FOR 3 YEARS, WITH A RICH MIX.I HAVE HAD 3 NGK'S IN MY LIFE WITH 3 DIFFERANT BIKES. 20 MINUTE RIDE TIME ALL COMBINED,ALL WET FOULED....TRY IT ALL YOU CAN DO IS SAVE MONEY

 

[Bruce]

ZKDKX... have the same problem following son on his PW 80. Had to go to a BR7ES. Helped a lot, but still foul. Every ten minutes or so would have to scream it to clean it out. Now that my wife is thinking of trying dirtbiking, I've got to come up with a more permanent solution.

Hotrodky, what Champion did you buy... I'm sure willing to give it a try.

 

[atc3434`]

Originally posted by HOTRODKY428
GET A CHAMPION,I HAVE BEEN RUNNING THE SAME PLUG FOR 3 YEARS, WITH A RICH MIX.I HAVE HAD 3 NGK'S IN MY LIFE WITH 3 DIFFERANT BIKES. 20 MINUTE RIDE TIME ALL COMBINED,ALL WET FOULED....TRY IT ALL YOU CAN DO IS SAVE MONEY

It may be just me, but there is a reason almost every bike comes with an NGK. :silly:

But it comes down to proper jetting, and how you ride. Honestly, you can have the perfect spark plug, and the perfect jetting, and you will still occasionally foul plugs. Solution... open the throttle, more than once every 5 minutes. :aj: In all serious though, a 2 stroke engine is designed to be revved and have a load on it. Without some rpm and decent load, your combustion temperature isn't going to be hot enough to keep that plug from fouling, not matter how hot a heat range you run. Some of these fella could probably explain this a little better than that, but basically you need some load, and to make some power, to keep everything happy with a 2 stroke. Real good oil (Amsoil) and proper jetting goes a Long ways though... :thumb:

 

[Tom Ludolff]

Youre pilot jet is probably too rich. I can putt around on my '03 KDX 220 forever without fouling. Can't say that for my '01 KX500 though. No matter how lean I jet it and how hot a plug I use, the plug is always black from putting around. MX bikes definitely have to scream, but the KDX are pretty putt-putt friendly.

 

[ZKDX]

i went from a 320 to 300 main...i have a 290 and 280, but i was afraid to drop any leaner just yet....btw: dumb question was is the proper way to do a WOT plug chop...do you need to be a mach1 or can you be in 1st gear WOT and kill it

 

[Roland C]

3rd or 4th gear is good for doing plug chops. Doesn't have to be top gear, but there should be a load on the bike, which first gear doesn't always give you.

 

[Bruce]

pardon my ignorance, what is a plug chop and what does it do... Wide open throttle and hit the kill button????

 

[Tamean]

A plug chop tells you if your main jet is rich, lean or perfect. Only the main jet! Go through the gears (4, 5, and 6th) wide open, nothing below full throttle. Get to the top speed in that gear and hold it for a few seconds. Pull the clutch in and immediately hit the kill switch and hold it, until you stop. A sandy brown plug is spot on. You can be a couple sizes rich on your main and you shouldn't foul plugs, because it's only for full throttle.

Before you do a plug chop or any jetting, make sure you float is properly set. A high float will make everything rich.
When your putting around, the pilot and air screw are being used alot. If they're rich, there's your culprit to fouls. Also if you foul while going down long down hills, since there's no throttle, usually.

The plug should have nothing to do with fouling. I run a B9, and have never fouled, although, my bikes jetting is spot on.

Read both of these to learn to jet your bike, and say good bye to fouling.

http://justkdx.dirtrider.net/carbtuning.html

http://justkdx.dirtrider.net/floatlevel.html


Hope this helps,
Tamean

 

[ZKDX]

Since my bike has been sitting since sunday, it has been steadily dripping fuel, this isn't a new problem, but my attempts to correct to far have been few and ineffective. trying to measure that .08 with the fuel tube gauge coming out of the carb is a bit tricky, and since my floats are not attached to the tang hard to use any other method, i believe tonight i will try the trial and error. CAN any harm be done if i get the tang level to low, thus not filling the bowl completely with fuel?

 

[JasonWho]

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[ZKDX]

only reason i'm running a 30 pilot: new too jetting, just trying to get it lined out, but i have to assume my floats are no okay, since fuel is dripping from vent hoses while she sits in my garage right now.

 

[srhill]

Is your petcock turned off?

If your bike is leaning to the side on the kick stand it's probably gonna leak a little gas out the vent tubes. If I am parked for more than a cople of minutes I turn my petcock off.

JasonWho, what part of Bama do you inhabit? Me, Northwest corner.

 

[ZKDX]

petcock is off-although i've heard how particular the position is, i don't leave the bike on the stand i have it on mx crate, so it's not leaning.

 

[srhill]

Hmmmm.

The petcocks are sensitive. You may have a float highth issue that needs to be corrected but if the petcock is off it shouldn't leak much gas. I would start by pulling off the fuel supply line with something handy to catch the gas in and of course in a well ventilated area and find out where off on the petcock is.

 

[ZKDX]

i've done that. I've also taken apart the petcock put in new o-rings and still seems to drip no matter where it is at....will it just dripping be the cause of my vent line dripping....maybe i need to order a new petcock? (oh god!, that means i have to go to my dealer!, he's an idiot!)

 

[canyncarvr]

A too-high float level isn't going to make it drip...unless it is SO far off that with the floats jammed all the way to the carb body the needle still isn't being closed.

That's unlikely.

I don't see any reference in this thread to the input needle/seat.

Howcome?

That's the FIRST place to look given: gas off, bike not leaning, still drips.

Consider...with the needle/seat working properly why would it matter if the petcock leaked or not? It wouldn't. IF the bike is leaning to the extent the overflow is 'satisfied' before the needle/seat is closed, then you'll certainly have a bike that pees.

Again.......that's not the issue here. You mention the bike is on a crate and upright.

IF the needle/seat is bad it won't matter WHAT your float level is set to. It doesn't matter!

Back to what jim said...replace the needle. When you do that, use a cotton swab with a strip of wet-n-dry paper (4-600) wrapped over the tip and burnish the seat. In most cases, the seat is NOT a replaceable part...don't know about your carb in particular.

I've used this method to resolve peeing, leaking bike carbs many times. Also, btw, to clear up fuel starvation problems related to the needle sticking in the seat due to a ridged needle and/or gummy/corroded seat.

Skip the petcock (and the idiot dealer). Call sudco or carbparts and get an inlet needle AND a seat if yours is replaceable (it is if yours is a holley! ;) )

If your needle tip happens to be brass (as opposed to viton. Doubt it is brass), dress both surfaces with wet-n-dry, and that will probably take care of the seepage problem.

 

[ZKDX]

so if i read correctly i cause is probably my carb not shutting the fuel supply off to itself, regardless of whether the petcock is leaking? thanks canyn..i'll try that route, i have inspected the needle before, but it has been awhile, and as far as i know that could be the original from 87'

 

[JasonWho]

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[HOTRODKY428]

HEY CALL ME CRAZY BUT A USED CHAMPION IN MY BIKE HAS BEEN RUNNING FOR YEARS..I WILL GET THE # 'S OFF OF IT BUT ALL I KNOW IT WAS A USED PLUG..WITH AN EXPOSED KERNAL.....86 DODGE 318....WHEN I PUT IT IN IT WAS AN EMERGANCY...PUSH IT....IT FIRED AND HASENT STOPPED...ITS ABOUT .015 LONGER THAN A STOCK PLUG..BUT IT DOES NOT HIT...I WILL MAKE MY BEST GUESS THAT IT WILL FIRE ... NO MATTER WHAT....I WILL POST PLUG TYPE ASAP 1991 KDX