2002 YZ 426....Starting Problems

I was wondering if you might have a sugestion on where to go from here.

My buddy has a 2002 YZ 426. We have checked the carb. all jets and needle are stock. The air screw is out 2.5 turns. If we put a new sparkplug in, the bike starts with one kick and will start all day very easily. Once the bike cools down ( the next day) you can kick it all day long and it won't start. Looks like the plug is fouling....black and all carboned up. Could it still be a carb. prob. We are at a loss. Any suggestion would be appreciated.

Thank you in advance,

Darren Mahler

New orleans, La.

The air screw is out 2.5 turns. If we put a new sparkplug in, the bike starts with one kick and will start all day very easily.

The 4-strokes have a fuel screw not a air screw. I think this is where you problems starts. It sound rich - Turn the fuel screw 1 -1.5 turns out and see where you are at. What plug CR9E or CR8E?

I have a 2002 426 and mine would sometimes not start when it had been sitting overnight. The float was sticking so what u can do is- 1)turn the gas off when your not riding or 2) PULL the hotstart and choke and kick it over for 30 mins thats how i start mine to avoid taking off the carb

He is putting in the CR8E. We didn't know where to start with the "fuel" screw, but thanks for the tip. We will turn the screw in and see if that leans it out a bit. The only reason that it was out so far was that he has a white bros pipe on it and the jets are stock. My thinking was that it would be lean on the low end because of that. But you may be right because of the conditon of the plug.

Thanks for your reply, I appreciate the help.

Hmm thats a thought.....but we took the carb off and cleaned, checked and carefully replaced it. It is very unlikely that the float is sticking because if it was ...wouldn't fuel run out of the overflow line?

As soon as we change the plug the bike starts right up. We just have to find out why the plug keeps fouling.

When it gets cooler, I always have to pump the throtle a a few times before trying to start it, then the bike would fire right up.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now