hi. got an 400 the carb was plug this spring so i clean it all out. ran fine. let it sit for a couple weeks and took it out on the trail for a day. came home it wouldnt shift from high to low. high to n, ect with out shuting it off. found out it was idling at 2400 rpms and not like the 1250 rpms it should so i trun the idle down and now it would run at idle until u get the machine all warmed.

and it will only idle at 1575 rpms and then the next time u run it ur back up to 2400 rpms after u take it out and run it for a couple hours

drain fuel out and put new in
try turning the poilt jet a little and didnt help
clean the cartb again blew threw it all.
diagrams look good

any ideas??

 

Look for vaccum leaks between the carb and motor. Sounds lie you could have something loose or cracked in there.
This manual is for a 2002
Free Cloud Storage - MediaFire
I can't say I have had to fight with a carb on one of these, but hoe this helps
Ken

 

Welcome to the forum kwbkkfarm

Your 2004 AC 400 4x4 fis is powered by the Suzuki 376cc Engine and Suzuki's Duramatic Belt Driven Clutch...

Sounds Just like my 2006 AC 400 auto 4x4 fis it got to the point that the engine wouldn't idle when it warmed up , i had to increase the idle adjustment to keep it running causing the gears to growl when trying put it in gear when the engine was running , i had to start the engine while the quad was in gear and it would lurch forward or reverse when the engine would start ; when mine was new after riding it untill the cooling fan would come on there would be a little pop from the exhaust pipe when i turned the engine off ; the valve clearances were out of specifications (not enough valve clearance/way to tight) and making the engine run hot !

I had to adjust the valves to the correct clearance , the correct clearance for the intake valves are (0.02 in.minimum to 0.04 in. maximum) , Exhaust valves Are ( 0.09 in. minimum to 0.11 in. maximum ) i set the intake valves at 0.04 in. and the exhaust valves at 0.10 in. , after adjustings the valves it ran perfect better than it did when it was new !

There is a website that you can download a free Service and repair manual on pdf formatt , it's a free download i'm not sure if it covers a 2004 ac 400 4x4 auto but the valve specs. will be the same my 2006 has the fuel tank mounted between the frame and rear plastics , if your quad has the tank mounted up front getting to the airbox will need to be removed in order to get to the valve access covers you will have two covers one in front and one in the rear of the top end ; exhaust valves are on the left side and the intake valves are on the right side . (each valve cover has both an intake and exhaust valve)

You'll need a filler gauge a 10mm boxed end wrench to break loose the lock nut and a small pair of vice grips to hold the adjuster when you reti ghten the lock nut , also recheck the valve clearance to ensure that the filler gauge has just a slight drag between the rocker arms and valve stem before reinstalling the valve covers ; i should've given this part first you will need to remove your pull starter off first and remove inspection the plug so you can line up the timing marks then use a wrench or socket and turn the crank shaft bolt over to TDC ( top dead center of the compression stroke ) when your're at TDC of the compression stroke the rocker arms should have a little wiggle when both intake and exhaust valves are in the closed posision .

I always remove the spark plug and stick my finger in the spark plug hole , you'll feel pressure pushing again't your finger when you're on the compression stroke then keep turning the crank case nut untill you lineup the stationary mark with the mark in the inspection hole !

The website that has the service and repair download is www.k&tlawnmowerpartsworld.com , it's been awhile since i've been on the site but i think i have the correct url , if not one of the other members will chime in and correct me ; i hope this is of some help getting the job done !

williebee..........

 

i,ve check for cracks and there doesnt seem to be any. i just did set the valves but i got to get more fuel to beable to run it. lol

thanks to both of you