Won't idle over bumps?

[kc 300EX]

Ok, I don't know how else to explain it. I have an 03' KFX 400. Wiseco 440 kit, Hotcams, FMF jet kit, Big Gun slip on, +1000 Rev box....

Quad starts, idles and runs beautifully, except while I'm riding, and I pull in the clutch, it will stall unless I keep the revs way up.

Also, if it's idling and Im just sitting on it not moving, and I shake it (jump up and down on it) it will stall.

What gives?

[GPracer2500]

Carb float? Check it's set to spec.

[1987 trx350x]

sounds like your idle is too low or to lean. either turn the idle up, or enrichen the mixure screw or both. idle rpm should be between 1200 to 1500 rpm. theres also something in the float boat called a baffle. it contains a small amout of fuel in one spot for jumps, whoops, etc. this could be missing or broken.

[zeppelin]

i think its your clutch.

[kc 300EX]

It has nothing to do with the clutch. If the quad is in neutral idling and I shake it, it will stall.

I tried turning the idle up, even with it way up it had no effect on the problem.

I guess tomorrow Ill try the air/fuel screw..

Any other suggestions?

[jeremy_283]

my 400ex all of a sudden started dying after i had a load on the engine and then let off the throttle....... i think oil was getting past my rings...... got my cylinder bored and honed to the next size up and no more problems

[Iliketogofast]

I thought clutch initially but now you say that when you shake it at idle it stalls. Has to be the carburetor.

[kc 300EX]

So this is nice.

You're out riding, or maybe just getting out of the garage, you're stuck, need to move your quad by hand, you get off, pick it up by the grab bar, it stalls....

Every time...

[Aceman]

That definitely sounds like a float problem. Jumping up/down or picking it up by the grab bar would affect the fuel level in the bowl. Check your float.

[JOEX]

Loose wire or bad connection somewhere?

Might be a long shot:ermm:

[humblesquirel21]

my 300 would do that kinda crap bu ti was never willing to put any money into my stock carb cause iw as saving for an edlebrocl
but for what its worth once my stocker was gone the problems disapeared.

[Toadz400]

Take the bowl off and make sure everything is clean and the float isn't sticking. Make sure your fuel mixture screw is set right also.

[kc 300EX]

I took my carb apart, looked very clean, but I cleaned everything with carb cleaner anyways, blew it through all the openings and all the jets.

Checked the fuel mixture screw, its set at 3.5 turns out just like the directions from my jetk it say..

I'm completely stumped

[1fst400]

you dident check the float level tho. that may be out of spec.

[kc 300EX]

How do I check/adjust the float level?

[GPracer2500]

Originally posted by kc 300EX
How do I check/adjust the float level?

It's sorta hard to explain. This link should help: http://www.cycoactive.com/mc/trail_tips/tip_float_level.html

I normaly adjust the float level with the carb off the bike/quad--clearence is sometimes an issue. Move the float until the needle valve just touches the valve seat. I just turn the carb on its side and gently shake it a little to get the float to find it's "closed" or up position. If you just push it up with your fingers, be sure that your not compressing the spring in the needle valve--that will throw off your measurement. Measure the distance from the bottom of the float to the carb body (the interface where the float bowl screws on to the carb body). To adjust the level you bend the little metal tang that connects the float to the needle valve.

I don't know what the float level spec is for your quad. If you don't have a service manual (and no one chimes in with the correct spec) then try calling a local service department for the info.

I sure sounds like your float level is set too high. Lets say the factory spec is 18mm (a guess) then yours might be set at 12mm. The lower the number the higher the float rides in the float bowl before shutting off the fuel flow.

Again, it'd much easier to just show you in person than trying to describe it with words, but hopefully the above will help.

[kc 300EX]

That was actually a great explaination and it makes a lot of sense. I have a manual, tomorrow night I'll check to see how far out of spec it is. Hopefully this will solve my problem.

Thank you very much for the information!

[4TraxRider]

Casey, you try putting your petcock on PRI? Mine did that when I had a pin hole in my vaccum line. Got it replaced and its fine now, when and if it ever gets running again.