Backfiring

My 02 yz426f with cam mod is very hard to start in the cold and takes forever. When im kicking it before it finally does start or should i say IF it finally does start, it backfires alot does this mean im jetted too lean? or is the carb dirty or both? thanks

I have to get this resolved before saturday i have a race at earlywine indoor

You are not, by chance, trying to start it with the red hot start knob pulled out, are you?

No i made sure of that

My 02 yz426f with cam mod is very hard to start in the cold and takes forever. When im kicking it before it finally does start or should i say IF it finally does start, it backfires alot does this mean im jetted too lean? or is the carb dirty or both? thanks

I have to get this resolved before saturday i have a race at earlywine indoor

Is the hard starting in the cold just in the cold weather or has it done this since you put the cam in it. Does it start easy in the warm summer weather???

If its just since the weather turned cold its probably lean. Put a 2 size bigger starter jet in it and a larget pilot jet. That should help a lot. Also run a irridium plug in it. Way better starting. Yamaha sells winter formula motor oil. Its thinner and helps the engine start when its cold.

The starter jet is in the bottom next to the main and pilot. Its the short stubby little jet.

Give it a try. It works.

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