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Old 04-08-2012, 10:43 AM   #62714
Beastly Adventurer
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Joined: Sep 2009
Location: SE Denver-ish
Oddometer: 7,260
Originally Posted by shaddix View Post
Hey guys! I looked at my spark plugs today and they were black. So going by this guide it says to run it at full throttle and check to see if they're black or white or tan as a first step to determining jetting needs. Now considering that my plugs are already black, will that mean that if it's too lean at full throttle they won't be white? Do I need to clean the plugs first before I test for lean/rich mixture?

How old is your bike and how many miles? What's your gas mileage, has it gotten worse? If you've had the bike for a while the jetting may be fine. The two o-rings in the carb may be failing causing a rich mixture at all throttle settings. We spend most of our time on the needle circuit, so this would be the one start with. Since the USA bikes don't have an adjustable needle, you can't drop the needle one clip. This means that I'd check the needle for wear (smaller diameter would flow more gas) and check the needle jet for 'ovaling', another wear point on some bikes (larger hole, more fuel).
2004 DR650: 62,605 miles
2013 WR250R

Originally Posted by Threewheelbonnie View Post
"BTW, I don't do style. It's a dirt bike, not some girlie dress-up thing." -
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