My son is complaining that his Z-400 takes 5 or so minutes to warm up. It is February in New Mexico, which is rather cold,,,not cold like you poor schmucks up north, but not warm like neighboring Arizona. Anybody else's Z take a while to warm up?

 

nope mine warms up pretty fast

 

If it's hard to start and he has to leave the choke on for a long time, you may want to turn the idle fuel screw out 1/8 of a turn (maybe up to 1/4 of a turn).

tip: If he's able to cold start the ATV without the choke, you've turned the screw too much.

 

Corpsie is right on the money. And I thought I was the only one that did this.

 

Mine was running way lean when I picked it up new at the dealer. It would require choke and a lomg time to warm up. After a month or so I took apart the carb and found the slow jet partialy clogged. After I cleaned it, No more problems.