My Bike Is A Spark Plug Eater!

38 replies to this topic
  • 02YZ426

Posted April 10, 2005 - 02:50 PM


I can't stop this bike from eating up spark plugs &%$#@!? Its an 2002 426 and its been doing this since new. In fact it did it right at the dealership before I even brought it home. Usually if the bike starts up right away, then its good for the day, other times it will fire a second then die with a wet plug. I can clean it all I want, but in the end it will need a new plug. Its using a new plug at the start of every second ride. But the if the bike starts, it runs amazing. Any ideas? Here is whats done to the engine:

White Brothers E-Series pipe
HotCams auto-decomp camshaft
Electrex USA Lighting Coil

Other than that the engine is bone stock. Carb has stock jetting and has never been monkied with. What could be going on here? Thanks Guys. :naughty:

  • sleeman

Posted April 10, 2005 - 02:59 PM


Did you have the lighting coil installed when you bought the bike?

  • 02YZ426

Posted April 10, 2005 - 03:04 PM


No...The coil was just installed, so that shouldn't have anything to do with it. I think it could be carb related but I'm not sure. My dealer told me that these bike come from the factory set lean, but I cant see it, since the plug is always getting wet.

  • sleeman

Posted April 10, 2005 - 03:06 PM


Seems that its getting too much gas.

  • Jetsprint2

Posted April 10, 2005 - 03:42 PM


Way to rich. Lean it out and monitor the bike as you go (read the plug and listen for popping on decelleration for signs of being too lean). :naughty:

  • wr450fyamaha

Posted April 10, 2005 - 03:51 PM


yup, open up the air box or put a smaller jet in!!!

  • 02YZ426

Posted April 10, 2005 - 04:05 PM


See, thats the thing. It is popping on the decel right now, so wouldn't that mean I am too lean as it is? This is why I am confused about the whole thing. I was just out in the garage and I opened up the fuel screw to 2 turns out and that stopped the popping. So I cant see it being too rich. :naughty:

  • sleeman

Posted April 10, 2005 - 04:10 PM


Pilot jet.

  • Satch0922

Posted April 10, 2005 - 04:38 PM


you can be too rich on the main and still have popping on decel (fuel screw)

Rejet, check the AP squirt duration (even the 02's were too long from the factory.......not as bad as previous years but too long none the less).

  • Dolce_Grappa

Posted April 10, 2005 - 04:45 PM


Assuming you're not twisting the throttle, have you done the BK carb mod? My took some tuning after I changed the duration. When did you buy the bike? It could also be your float level or it's needle not sealing.
As already stated try leaner PJ.

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  • 02YZ426

Posted April 10, 2005 - 04:51 PM


Assuming you're not twisting the throttle, have you done the BK carb mod? My took some tuning after I changed the duration. When did you buy the bike? It could also be your float level or it's needle not sealing.
As already stated try leaner PJ.

Whats the BK carb mod do for the bike? So should I go leaner 1 size on the pilot then? or the main?

  • elburro

Posted April 10, 2005 - 05:59 PM


You might check with white bros. and see what jetting they reccomend for the pipe.

  • new2blu

Posted April 10, 2005 - 06:13 PM


I have had a similiar problem and am now trying an autolite spark plug instead of a NGK. I read somewhere that the NGK insulator is "porous" and fuel fouls. The Autolite plug # is 4303 and is about $2.50 at NAPA. I haven't had a chance to ride lately but will post once I do.

  • MXDAD65

Posted April 11, 2005 - 10:48 AM


I am having the same problem with my 04 450

  • Yak

Posted April 11, 2005 - 11:56 AM


My 2002 is sensitive to different brands of gas. I know that If I use Citgo from the 7-11, Im ok for a while. If I use the AM/PM brand im bound to foul on that same ride.

Try some VP 4-stroke gas and see if that clears up the problem. At least then you can rule out larger problems.

  • Chad76

Posted April 11, 2005 - 03:44 PM


Yeah, I have heard the same. It could be the type of gas you are using. Dont know what you call your gas over there but here in Australia most people run a premium unleaded. However I was told by a service guy to run standard unleaded, especially if you are mainly riding in the bush and not on a track. He said the premium tends to foul the plugs quicker especially if your doing more riding in the bush for you dont tend to have it opened up as much.

  • 02YZ426

Posted April 11, 2005 - 03:52 PM


I always run premium fuel but its only 93 octane. I think the the manual calls for a 95 but you cant get that high unless you by race gas. The highest I can get from the pump is 94 from Sunoco but I avoid using it because it contains ethonal. I wonder if I should start adding some octane boost to my fuel?

  • r1ray

Posted April 12, 2005 - 04:00 AM


My 02' did the same thing since new as well. I used an ega machine and found that it was running way too rich. The exhaust gas analyzer read the bike was way rich on bottom and in the middle, so I dropped the needle one clip and turned my pilot in. I think its at 1 and 1/4 out. Been running killer ever since. I wish I had extra cash to buy an ega machine. Hope this helps. :naughty:

  • 02YZ426

Posted April 12, 2005 - 01:31 PM


Sounds like its worth trying. Thanks :naughty:

  • desertfox89

Posted April 12, 2005 - 02:41 PM


i agree with them your running to rich i had the same problem with mine it took awhile but Finlay got it dialed in .what elevation are you riding in and temp and whats your carb settings right now i ride at 3000 to 7000 elevation and when i bought the bike from the dealer it was set for sealevel they didn't bother changing it for me . I'm running 155 m, needle #3 pos, and just went to 40 pilot jet. with about 1.5 turns out on the pilot screw seems to run and start better for me after many spark plugs finaly happy

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