2001 426 PLUG FOULING



9 replies to this topic
  • THUMPERPWR

Posted October 21, 2001 - 12:34 PM

#1

MY BROTHER IN LAW KEEPS FOULING PLUGS, 12 OF THEM! THE DEALER FIXED THE THROTTLE POSITIONING SENSOR & RE JETTED THE CARB , ITS STILL FOULING! HELP! [THUMP ON !]

  • sirthumpalot

Posted October 21, 2001 - 02:59 PM

#2

is it foulding while he's riding, or only during starting? If only during starting, is it only during the first cold start of the day or during any start? Also is he following the starting routine properly?

  • THUMPERPWR

Posted October 21, 2001 - 04:00 PM

#3

its fouling after i ride it all day. try to start it before next ride and it will not start! i am doing all the starting procedures just like they say to.i have put a 158 main jet and a 40 pilot jet and still fouling every other time i ride it!!! basically i must change the plug every time i want to ride it, and i am about to shoot it!!!please help!!

  • DTRS

Posted October 21, 2001 - 06:21 PM

#4

MY 01 WAS FOULING PLUGS TO, WHEN I WAS USING THE NGK CR8E AND I CHANGED TO THE CR7E, BINGO THAT SOLVED MY PROBLEM BEFORE I DID THIS I GOT TWO RIDES A PLUG HOPE THIS HELPS YOU GOOD LUCK.

  • Ramrod

Posted October 22, 2001 - 03:12 AM

#5

My 01'426 fouled about 8 plugs when new. I played with the jetting a lot, but found that the stock jetting was best. Mine did the same thing, a new plug for every ride ... my eigth plug must have been a good one, because I've been riding on it ever since with no problems. After it quit fouling, 3 rides later I did the bk mod (which didn't seem to change much in my case) and I still have no problems.

Some other guys I know with 426's said theirs gave them trouble too in the beginning, and maybe after 5 - 6 good long rides it gets better?

How many times have you ridden your bike?
Do you have the starting routine down?

Good luck and be patient! You'll get it!

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  • forloop

Posted October 22, 2001 - 06:04 AM

#6

If you do a search you will see that there was several of us having this problem. BK passed some info a long about carbon build up on the exhaust valve. Me and jaybird switched to racing fuel and the problem went away. I run a 50/50 mixture race gas and pump gas.



------------------
Rick
01 YZ426F #85 Vet C

  • sirthumpalot

Posted October 22, 2001 - 07:25 AM

#7

My '01 started having this same exact problem but it went away when I switched from Mobil brand gas to Chevron brand gas. The bike seems to run much better too (and my truck pings less with this gas as well, Mobil in my area must be poor quality gas). The jetting is 100% stock and I'm at sea level (S. Florida). Before you shoot anything try switching brands of gas.

Also instead of replacing the plug, just shoot it with some carb cleaner and that should fix it right up. This saved me from buying a few plugs before I switched brands of gas.

  • lou

Posted October 24, 2001 - 02:57 AM

#8

It amazes me how Yamaha let this problem slip through the cracks......a good manufacture would've had a recall! If your new to this sight, do a search on "Plug Fouling" you'll be amazed . My bike had this same problem(intermittenly).I replaced my CDI with a 2000 CDI and have not fouled a plug since.

  • John_H

Posted October 24, 2001 - 05:27 AM

#9

The gas thing catches my attention. My jetting seems right and 2001WR runs/starts great. Then all of the sudden it won't start (fouled plug). Only happened twice in 1000 miles. The first time I'd stopped to ride up to engineer pass in CO which is about 12,000+ feet, but the bike started okay after that for a short ride, then fouled plug. I figured it was the altitude. Second time fouled just out of the blue though. Not really a problem if I have the tools to pull the plug, but makes me wonder what's the actual cause. Likely a combination of things.

  • sirthumpalot

Posted October 24, 2001 - 06:06 AM

#10

I reasoned that it was the gas because of this. When I first got the bike I would always buy gas at the station near the track (not a big name station). I did not have any fouling problems at all. Then I started getting gas at a Mobil station near my house before I started the trip to the track. This is also when my plug fouling started (absolutely no changes to the bike, not even the fuel screw). I then got suspicious and started getting gas at the chevron across the street from the mobil station and the plug fouling went away completely (been on the same plug for many weeks now). Again no other changes. I only ride at one track, I've made absolutely no changes to the motor and the weather here hasn't changed that much. It's possible that it could be something other than the gas, but I'm 95% sure that the gas was a major contributing factor. It would be interesting to see if someone else could duplicate this. I hope that this helps!





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