Bike stalls

I purchased a new YZ450F in March of 2004. I have only started it a few times and let it run for a couple of minutes, then turned it off. The bike has now been sitting for 5 months. When I start the bike, it will only run with the choke out. Once I push the choke in, it stalls.

Can anyone give me some advise. This is the first time that I've owned a four-stroke. If you can help, please do so

There is probally dried gas residue in some of the jets. The reason it will only run with the choke out is because it is greatly increasing the amount of gas going to the cylinder, which is making up for the clogged jets.

In simple terms, clean your carb, spraying carb cleaner in every hole. :cry:

Yes clean the carb, it's goo'd up for sure. If you're going to store the bike like that, at least add some sta-bil to the gas and drain the carb dry.

Thank you for the help. I appreciate it.

because it is greatly increasing the amount of gas going to the cylinder, which is making up for the clogged jets.

I agree, it's the clogged jets, but the choke doesn't greatly increase the amount of gas going to the cylinder. It increases the fuel:air ratio by limiting the air coming through (hence the name, choke). Not to ping on you, just a clarification.

I think everyone and their advice is on the right track. The sta-bil can be skipped if you turn the petcock off while it is still running and let it burn what is left in the system. That way no fuel to varnish. Good Luck BTW I always shut off the gas and let it run out, even if I am going to ride it in a few hours. Nobody can twist the throttle and flood my bike if there is no fuel in the bowl.

because it is greatly increasing the amount of gas going to the cylinder, which is making up for the clogged jets.

I agree, it's the clogged jets, but the choke doesn't greatly increase the amount of gas going to the cylinder. It increases the fuel:air ratio by limiting the air coming through (hence the name, choke). Not to ping on you, just a clarification.

Actually in this case the choke is an enriching circuit more than a choke. It does increase the fuel flow and does not restrict the air flow (actually allows more air I believe).

Pardon my lack of experience with this carb, then. So the chocke circuit opens another pathway for the fuel to flow through the carb? I would check the manual, but I'm overseas right now.

Pardon my lack of experience with this carb, then. So the chocke circuit opens another pathway for the fuel to flow through the carb? I would check the manual, but I'm overseas right now.

Yes, that is correct. It is not the traditional style choke with a plate that covers most of the throttle opening.

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