2005 YZ450 only runs with choke on?

I looked at a YZ 450 tonight that appears to be in really good shape but for some reason it really didn't want to run unless the choke was on. The owner said the bike has sat since last July without being run but that it had Stabil in the gas when it was parked. Has fresh gas in it now but it still only runs with the choke on. Now it was about 35 degrees out so I'm wondering if that had something to do with it? I really can't beat it for the price but I don't want to have a major issue trying to get it running correctly. Could it just be the temperature now or maybe the carb just needs a cleaning? Thanks for any help.

I looked at a YZ 450 tonight that appears to be in really good shape but for some reason it really didn't want to run unless the choke was on. The owner said the bike has sat since last July without being run but that it had Stabil in the gas when it was parked. Has fresh gas in it now but it still only runs with the choke on. Now it was about 35 degrees out so I'm wondering if that had something to do with it? I really can't beat it for the price but I don't want to have a major issue trying to get it running correctly. Could it just be the temperature now or maybe the carb just needs a cleaning? Thanks for any help.

clean the carb and pay extra attention to the pilot circuit.

its old so clean the carp and check the valves

its old so clean the carp and check the valves

worlds-largest-carp.jpg

Sorry, I just couldn't resist.

Thanks guys, if I buy it tomorrow I'll make sure to clean the carp first.

now thats funny.First laugh i've had tonight

+1,

debris plugged pilot jet.

I have a very similar story. I just bought an 04 yz 450 back in Dec. and it did the same thing, as soon as you took it off choke it died. I cleaned the carb and it didn't help ended up being the valves,wasn't very expensive and now it runs like a raped ape good luck

I have a very similar story. I just bought an 04 yz 450 back in Dec. and it did the same thing, as soon as you took it off choke it died. I cleaned the carb and it didn't help ended up being the valves,wasn't very expensive and now it runs like a raped ape good luck

Were the valves out of adjustment or not sealing properly?:thumbsup:

Were the valves out of adjustment or not sealing properly?:thumbsup:

What he said? Just the valve lash or did it need a complete valve job?

I have a very similar story. I just bought an 04 yz 450 back in Dec. and it did the same thing, as soon as you took it off choke it died. I cleaned the carb and it didn't help ended up being the valves,wasn't very expensive and now it runs like a raped ape good luck

This simply doesn't make any sense.

Three out of five of the valves were to tight, after we shimmed them up it run's great.

At least it was a simple adjustment. I'll be starting with the carb and see what happens.

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