I have an Eiger here, not sure on year. I believe 03 or 04. I have an issue with an intermittent rough/ low idle, and a midrange stumble. It had a really funny low idle at first and the idle adjustment **** had zero affect on the idle. I could go all the way up or down with no change. I pulled the carb and cleaned it out 3 times now, adjusted the choke, replaced spark plug, cleaned and oiled air filter, fuel screw is at about 1.5 turns out, checked compression, checked valve clearances, did a leak down test, and checked generator output and battery condition. Everything checks out. Seems to do this with the fuel valve in run or pri position. It also will have a stumble at about a quarter throttle, runs out fine. If I run the quad in that 1/4 throttle and come to a stop it will stall out. I pulled the needle hoping to find it was adjustable, but it isn't. I don't know ehat else to check. Funny thing is I did all the checks, put it back together and it seems to idle fine, but still has that stumble. Old spark plug was pretty black, and if I hit the choke on the quad dies right away.

 

These model are known to have an bad flywheel,the old wheel has glued on magnets and when the magnets come unglued they will move or rotate which will cause an change in timing.Should have machined flywheel with magnets machine in flywheel.

 

I have read a lot on the poor quality flywheels, if a magnet comes unglued wouldn't it not run at all?

 

I am deeply sceptical about the loose magnet theory. I have had an Eiger with this fault, and it wrecked the stator, as I guess the magnet was attracted to the stator, next magnet hit it, it then jammed between stator coils and other magnets, looked like a bomb had gone off with magnet shrapnel everywhere.

If the plug is a bit sooty, you are probably running rich, seeing as you have been altering the idle mixture screw, this could be the problem. The choke cable can get too short, strange I know, but the outer rusts and has this effect. Also the handlebars can rust under the lever, preventing it from working properly.

A weird fault I had recently was a sooty plug and poor performance when hot. Turned out to be someone had left the tap on PRIME and filled the sump with fuel. It had then stood for a while, any fuel in airbox had drained out, (it is usually full of fuel when someone does this.) As it had an oil change a week before the symptoms started, it was a while, and three carb cleanings, before I checked the oil and found the sump full of fuel/oil mix.

 

Yes it will run in the early stages of magnets coming loose...I have had about 20 of this atv with this problem..Some would run with no power but idle, some would run an backfire when accel.,Some wouldnt run but would fire,some would lock down engine when magnet came loose and lock into stator,some would run rich it all depends on all many magnets have came loose.I just finished one last week no power above mid range,,vatted carb and installed new repair kit and had to teardown an replaced flywheel it only had 1 magnet that came loose.

 

You also may want to check to see if fuel cut off value[petcock] assy to see if the vaccum line on the back side has fuel in it if it wet when remove line for fuel value then the diapham inside is bad an letting fuel into intake before the carb an you wouldnt be able to adj. out,if bad then put an aftermarket value without the vaccum diapham in it..If remove the line an its dry inside after you run atv afew minutes then my guess would be bad flywheel just opinion from what you have already have done so far.

 

Thanks for the assistance so far. I haven't pulled the flywheel yet, I think is going to be the next move. I pulled the carb and cleaned it again, adjusted float level, checked the petcock, and adjusted the fuel screw everywhere from 0 turns out to at least 3 with no change. Now it does idle fine, but about 1/4 throttle it starts stumbling, if I rev it hard it runs fine and comes back to idle fine, but if I hit that range and it starts stumbling and I let off throttle it will stall out everytime. I "could" live with it, but it stumbles right it that speed I like to have for moving it around. Will pull the flywheel and report what I find.

 

You wont have to pull flywheel to check just the left engine cover an d after you do that you can see flywheel magnets..Thanks for the update and good luck an get back with us

 

Didn't get a chance to see the flywheel. I didn't realize the whole engine side cover had to come off. I called the owner of the quad and he said the flywheel and stator had been replaced a couple years ago. To his recollection it was replaced with oem Suzuki parts. I am assuming they found fault in their product and the new oem part would have been an updated one. He is going to pick it up and try it out.

 

He came and picked it up, said he would give it a shot. Funny thing is, his buddy dropped one off almost identical to it, maybe a year or two newer, and it does the exact same thing. Stumble a bit off idle. Says it has always done it, weird.