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2006 CRF450R fouling plugs HELP!

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My buddy put a brand new WB Carbon Pro II on his 2005 CRF450R and almost immediately fouled out the spark plug. Went from a stock 168 main jet down to a 158 main jet and problem still exists, new plug fouls after two rides with a heavy blacked-out carbonized plug. Fuel/air screw adjustment did not help either. We are thinking maybe pilot jet needs to be leaner.

Anbody willing to help us out on this please?

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What else was done when you did the pipe. Clean the carb? Anything? Make sure the choke is seating for one thing to check. Then start looking at the float level. Even with the jetting being stock it wouldnt suddenly belch smoke with a pipe change...something else is going on...

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If its fouling plugs its probably too rich... My friend leaned the jet on his YZF and it no longer fouls plugs, he was fouling them every ride.

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Actually, it's an '06. WB recommends a 158 main jet (168 stock) and lowering the clip (richer) 1 step.

When I put the pipe on I changed the main to a 162. The bike had a hesitation in the powerband when I rolled on the throttle. I'm not talking about throttle response. The power would start to come on, then dip, then come back.

So I tried changing the clip richer as recommended. This got rid of the hesitation but the plug was covered with black soot and eventually fouled.

I've gone to a 158 main and that does not help. So now I'm thinking it's the clip position. I'm going back to stock and if I'm still getting the hesitation, I'll try getting rid of it with the fuel screw.

Does that sound like the best plan? Anyone else jetted an 06 with the CPII?

Thanks! Mark

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Actually, it's an '06. WB recommends a 158 main jet (168 stock) and lowering the clip (richer) 1 step.

When I put the pipe on I changed the main to a 162. The bike had a hesitation in the powerband when I rolled on the throttle. I'm not talking about throttle response. The power would start to come on, then dip, then come back.

So I tried changing the clip richer as recommended. This got rid of the hesitation but the plug was covered with black soot and eventually fouled.

I've gone to a 158 main and that does not help. So now I'm thinking it's the clip position. I'm going back to stock and if I'm still getting the hesitation, I'll try getting rid of it with the fuel screw.

Does that sound like the best plan? Anyone else jetted an 06 with the CPII?

Thanks! Mark

boy in Georgia this time of year i would sure not be raising the needle richer with the junk pump fuel you guys got over there ( it is odd to foul a crf but oh well ---anything is possible )

i would go back to stock needle position and glass bead the plug clean and do some top end runs and see what main jet it really wants in it and start over,---righ now i am ending up 1 clip leaner on the stock needles :ride:

that one clip richer in the needle could vary well be hurting you :thumbsup:

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boy in Georgia this time of year i would sure not be raising the needle richer with the junk pump fuel you guys got over there ( it is odd to foul a crf but oh well ---anything is possible )

i would go back to stock needle position and glass bead the plug clean and do some top end runs and see what main jet it really wants in it and start over,---righ now i am ending up 1 clip leaner on the stock needles :applause:

that one clip richer in the needle could vary well be hurting you :ride:

Agreed. In Geogia it's gotta be hot and humid. All the more reason to go leaner. The humidity can kill good jetting. Lean is mean, Baby! :thumbsup:

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Turn the choke off.

I road for about 5 mintues the other day and my bike starting cutting out. I had just removed the battery so i figured the positive was bouching off the frame. I pulled over and took off the seat and i was like damnit. Its not the terminal. I was about ready to get a tow back tot he truck and my buddy asked if the choke was on. I reached down and i was like shi$. It fired right up. You got to remember to turn that thing off

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