Question about 2004 Honda CRF 450 R

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2004 CRF450R Ok so the bike back fires like crazy when i start. Now for the last three years this bike has been perfect. It has a white brothers pipe, I have jetted the bike for the pipe this is all old news. The bike has been sitting for a year. The last time it has been ridden is 1 year ago. So i took the carb off and went through it, cleaned all the jets and went through it throughly. I checked the valve clearances they were perfect, checked the timing it was perfect. I oamed the coil it was .4 and tolerance is .1 - .3 I am not sure if this is the problem. So for fun I changed my main jet to a 180 and turned my pilot screw out 3 turns, it ran better for 3 minutes and went back to the same to blowing flames out of the exhaust.

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Could be as simple as a new spark plug needed.


Posted on Jan 23, 2009

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