08 YZ450F plug


5 replies to this topic
  • 08YZ450Derek

Posted March 21, 2009 - 03:30 PM

#1

What is the plug supposed to look like on a properly jetted 450? Since the weather warming up, my plug color is off white color, with no residue. Its very clean with 2 hours on the plug.
Am I too lean? Jetting is stock, only mod is a ride eng. fuel screw. What jetting should I be running at 500ft, 70-80 degree weather? Only have a RS-2 slip on for mods. Thanks!!

  • jjj109

Posted March 21, 2009 - 06:46 PM

#2

What is the plug supposed to look like on a properly jetted 450? Since the weather warming up, my plug color is off white color, with no residue. Its very clean with 2 hours on the plug.
Am I too lean? Jetting is stock, only mod is a ride eng. fuel screw. What jetting should I be running at 500ft, 70-80 degree weather? Only have a RS-2 slip on for mods. Thanks!!


it sounds like your running a lil lean. 1 up on the main jet and 1 down on the clip for the needle

  • grayracer513

Posted March 21, 2009 - 08:08 PM

#3

If you are running unleaded gas, the plug should look about as you described it; smoky white. It is the lead in leaded fuel that gives color to plugs. With unleaded reading plugs provides no meaningful information.

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  • 08YZ450Derek

Posted March 21, 2009 - 08:26 PM

#4

Thanks Greyracer, It runs good at the track. I just pull the plug after every ride and replace them. I do save them to compare, but its looking all smoky white and clean. No residue (soot) and the bike runs great, just have to adjust the screw to weather differences. Always a pleasure to get good feedback for my Q's. Thanks again!:thumbsup:

  • grayracer513

Posted March 21, 2009 - 08:51 PM

#5

I just pull the plug after every ride and replace them.

Wow. First four stroke?

I change my plug whenever I can't remember when I put the last one in. Seems to be something like once a year. The last one I replaced looked new.

As far as jetting goes, look through this:

http://www.thumperta...699#post2881699

  • 08YZ450Derek

Posted March 22, 2009 - 07:53 AM

#6

Yeah, first 4 stroke. Maybe I should leave the plug alone, the bike starts 1st or 2nd kick cold right now. Hot its like 1 kick, w/ hot start. It sounds like my jetting should be okay, the bike pulls good on the track. I do have to clutch it in the corners to keep the power in the meaty area though. Feels soft off the bottom (compared to my 98 KX250) even added a 50T rear.
Otherwise I am trying to stay off the clutch so much. First practice I was revving it out, and the clutch was fading. So I stopped doing that and now I try to roll on the power and let it build. Love this bike though, suspension works really great and I am 220lbs! I might need to play with the clickers, I have it set up MXA specs. Any thoughts?





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