Plug Fouling

Mike,

Good guess! I did go to VT from 87-92 (BS) and at night from 93-97 (MS)

I am not surprised about the bar fight, probably at the Sundowner.......

I'll keep an eye out for you on Sun. I drive a Dodge Ram 2500, dark blue and have a 3-rail trailer.

I am not sure what class I am going to ride this year. I rode novice the last two years but I think that I am going to try intermediate this year. Maybe vet, but I doubt it. I missed the first two races, so it is going to be hard to finsih well this year.

Currently I am just running regular 91 octane in my '01 426. Seems to do pretty well. I get it at the truck stop at HWY 52 and I25, no ethanol in that gas! That ethanol crap sucks.

MikeO/Hokie... Colo Spgs here...

We put a CR7E in my bud's bike at Aztec on Sunday. It didn't cure

his problem. As a matter of fact, his problem worsened. He asked me

to take his bike out to see &%$#@! was wrong. The first two laps I

thought he'd been smokin' out behind the trailer as the bike was

spot on. As I rode laps 3 and 4, it started getting worse, acting

almost as if the plug was fouling. It was missing everywhere in the

range, blubbering, popping on decel, etc. Thinking it might be getting

a little hot (it was 55F out) we put the 8 back in. Did the same thing.

Weird.

I finally got a chance to check my jetting and I'm running 158M/2C/40P

and my fuel screw wherever it needs to be to run right. As far as

fuel, I'm currently burning some non-ethanol that I brought back from

Texas. I might go the race gas route this year as I hate that oxy

crap.

Good luck and have fun at the HS this (?) weekend. FWIW, the word of those events never makes it to COS.

Merf

Candlkirk,

I had the same exact problem that you're having with my '01. Never fouled a plug while running or while the motor was warm, only after sitting in the garage overnight it mysteriously wouldn't start the next time I tried to take it out until I swapped the plug. The solution for me was to switch brands of gasoline. After going through 3 plugs in 3 rides I switched from Mobil to Chevron. Since changing brands I have not fouled a single plug. I'm even using a plug that had fouled with the Mobil gas which I cleaned up with carb cleaner and it now has probably 6 or more rides on it with no trouble at all. My jetting is 100% stock, even the fuel screw, and I'm at sea level (south florida). This may not be your problem but it's worth a try.

Forgot to mention, when I was fouling plugs with Mobil gas the temps were in the 80's to 90's.

[ December 11, 2001: Message edited by: sirthumpalot ]

Originally posted by Merfman:

MikeO/Hokie... Colo Spgs here...

We put a CR7E in my bud's bike at Aztec on Sunday. It didn't cure

his problem. As a matter of fact, his problem worsened. He asked me

to take his bike out to see &%$#@! was wrong. The first two laps I

thought he'd been smokin' out behind the trailer as the bike was

spot on. As I rode laps 3 and 4, it started getting worse, acting

almost as if the plug was fouling. It was missing everywhere in the

range, blubbering, popping on decel, etc. Thinking it might be getting

a little hot (it was 55F out) we put the 8 back in. Did the same thing.

Weird.

I finally got a chance to check my jetting and I'm running 158M/2C/40P

and my fuel screw wherever it needs to be to run right. As far as

fuel, I'm currently burning some non-ethanol that I brought back from

Texas. I might go the race gas route this year as I hate that oxy

crap.

Good luck and have fun at the HS this (?) weekend. FWIW, the word of those events never makes it to COS.

Merf

What is your bud's jetting? Mine is either exactly like yours, or one leaner on the pilot. (I can't remember right now). When I first got my '01 426 I took it to the track, did 3-4 laps then it started missing, and fouled the plug. It was used (barely) and supposedly the guy who had it before did not know how to ride it very well. Anyway, I went back to the dealer pretty pissed off and got the standard "must be the jetting" blah blah blah.

Well, in this case, they were right. The jetting was so far off it was ridiculous. So, I did a little research and came up with the same combo as you have. Also, check the float bowl height, mine was out of spec, so I fixed that also. Ever since then, I have not had any problems. I have also not been riding in the colder weather, so I guess I will have to wait and see what happens this Sun.

Check out http://vdr.srac.org/ for the HS info.

Originally posted by Merfman:

As I rode laps 3 and 4, it started getting worse, acting almost as if the plug was fouling. It was missing everywhere in the range, blubbering, popping on decel, etc.

crap.

Merf[/QB]

EXACTLY! Thanks Merf. I hope its the gas. I have not fouled a CR7 yet but it did not cure the problem completely like I first thought. You are running the same jetting I was in the summer before I did the BK mod. Now I am running 162/#2/42 (Guys with the BK mod at sea level run a 168). I have tried to go leaner but it doesn't run well.

Hokie, I just made a special trip to I25&Highway 52 because I also heard there was no Ethanol there. Will try it this week, otherwise its race gas. Look for me on Sunday. BTW, I am from VA and went to VT for a quarter.

With the 01 model..which is what I have...the BK mod did wonders for me! I bought mine in Oct of 00'..it was still nice out for the first month and a 1/2 that I owned it..when it got cooler I started having issues w/starting. The plug would be all black and suity..just nasty. Since the BK mod my jetting is stock 42 pilot/1 richer clip position on stock needle, 168 or 165 main depending on temps for the day and 1.5out on the fuel screw. My plugs are nice tan/white and very clean looking..no build up. We rode this past Saturday, it was 35-37 degrees at start up time. I give it two full priming twists of the throttle and it fired 3rd kick..KCHusky did the BK at the same time..we did them together actually..he is jetting similar except w/a 45 pilot and race fuel..his started first kick..niether of us have changed plugs since September. Might want to give the BK a try. Also, before starting, drain the float bowl, then let it refill w/fresh stuff..mine has always seemed to start funky w/gas that has sat in the bowl very long. Hope you guys get em' dialed. Jason

Hokie,

Kevin's jetting is the same as mine, right down to the number of

discs in the E-series pipe. I didn't think it was jetting since it

ran fine the first 2 laps. I'm pretty baffled. He had to bug-out

before we could really figure out what was going on.

BTW, I mentioned that my tranny broke... funny how a $0.45

spring can stop a $6000 mo-sickle but I'm glad that's all it was.

Merfman, if you figure it out you are a GOD! Several of us have had this problem for over a year. I have a new CDI and carb on my bike from last winter, which seemed to fix it. The bike ran great all summer. I thought the gremlin was gone. Cold weather brought it back. Then I thought the CR7 fixed it. It helped alot, but this past sunday it was happening again, just not as bad (the bike has not actually stopped dead yet). I am pretty mechanically inclined, and have not sorted it out. Neither have two dealers. The problem is intermittent, so sometimes you change something and you think its fixed, but then it shows up again later. I hope its the gas, but I went that route last winter without sucess...

I see a CRF in my future.

My inside sources say that they can fix the problem with a

session on the EGA. I just *might* have to find out this year.

It's just that paying about $120 to get my bike "jetted right"

(when it runs like a scalded dog) sticks in my craw.

I can buy lots of plugs for $120 and I can now change one in

under 10 minutes.

Merfman: Mine was on the EGA five times last winter. CO was adjusted for 1 1/2 percent, if I remeber right. Didn't help in the least. ITS NOT THE JETTING!

Mike O, thanks for the input! FWIW, I didn't think it was the

jetting either, there are just too many things that change at once

for it to be a simple problem. I'm just glad I didn't get one that

fouls plugs while riding. One of the guys I occasionally ride

with at Aztec had one that would foul just about any time.

Fouled over a triple. Cost him a broken leg, arm and various

contusions. He's now on a YZ250.

I saw you're headed for a CRF eh? Best of luck!

Yeah, thanks Merfman. If you are curious about this problem look up the thread "fouled plugs=foul mouth" from last winter. Its as long as a Russian novel. There were alot of guys with the problem, and many did seem to be from high altitude.

I am going to try race gas (again), but I am pretty fed up with this YZF. I really thought I had it with the CR7 plugs. Its better but still not good.

I have a WR250F that never misses a beat, and I will keep it so I will still be riding blue in the RMEC series next year. But this plug fouling YZ426F is getting to be too frustrating-and risky. Sunday it sputtered on me like it was going to cut out while I was doubling a long whoop section. A good friend of mine broke his hand by endoing on his 426 in that same section.

So its going to be replaced, I need a reliable bike for the HS series that runs no matter what the temp outside. But what do I do with this YZF? I can't sell it and not tell people it has a gremlin.

Mike,

I read about 99% of last winter's thread and I have enough firsthand

experience to point me to a laundry list of gremlins. IMHO, *one*

thing can't cause this many similar, but different, problems. On one

hand you have bikes that:

a) foul while riding no matter what the temp

:) run fine on a new plug but won't start the next day (mine) when the

weather gets colder.

c) run fine in warmer temps but are all over the board once the

temps cool off.

On the other hand you have bikes that don't miss a beat. Pretty

confusing. My biggest complaint is that I wish Yamaha would

ante-up and say "Yep, we got a problem" and help us fix the damned

things. Somebody is gonna get killed on one when it fouls a plug over

an obstacle and they're gonna get sued.

What to do about your bike? Man, that's a tough one. Maybe

sell it to someone in Florida who won't care if it fouls plugs when the

weather drops below 35?

Let me know if you decide to race Turkey in March. Unless something

happens, I'll be there and I'd like to meet ya...

Merfman, I agree with everything you said. We should get together and ride sometime. I ride at Rampart and Taylor park/Crested Butte alot.

I have a HS this weekend at Berthoud. I am going to bring my WR250F just in case my YZ426 doesn't run during practice. The course is pretty wide open, and mostly motocross tracks, so I may get my butt kicked with the WRs soft suspension and lower power. There are a few obstacles I do with the YZ that I know I won't try with the WR. Should be interesting.

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