Hi guys,
I'm new to the site and desperate for some advice. It seems most of you are pretty knowledgable, so any tips you could give me would be greatly appreciated. I have a '99 arctic cat 500 4x4, which I purchased new. It has beeen a great bike and overall I really have no complaints. It's been sitting up since last hunting season when it was parked in descent running condition. When I went to pull it out of the shed the other day for the first time in months, I ran into some problems though. To make a long story short, I've installed a new batt., plug wire connector, plug, fuel supply line, changed the fluids, cleaned the carb., cleaned the air filter, and ran some fuel system cleaner in with the new fuel. But I still have a problem that I cannot seem to figure out. The bike idles fine and runs good through first and second gear, but as soon as I shift to third and the load on the engine becomes greater, it misfires and bogs down terribly. I've done everything I know of to remedy this situation with no luck fixing the problem. I don't think it's the coil because it's not a constant thing (in idle and through 1st and 2nd). One of my friends said something about valve gap, but I'm not so sure. This problem is a first with the bike and I don't think the source of it is anything major. I just don't want to take it to the dealer and spend big $ to fix a simple issue. Thanks in advance. Please help!

 

Only thing I can think of is the valves. They do need to be adjusted from time to time. You can do this yourself if you have about an hour or two.

That is all I can think of. [img]i/expressions/face-icon-small-sad.gif[/img]

 

i agree it is probably a valve that needs to be adjusted or is sticking. we just had that happen to an old motorcycle someone brought us that they couldn't get running and turns out it was the intake valve sticking so we set it and it purrrrs like a kitten now. i can't remember the clearence though i am sure someone else can give you what that should be. and did you also make sure your carb is set correctly? that happened before with my dirtbike to i was running it to rich and i leaned that baby out a lil bit and back to doing wheelies in 4th gear.

 

Well, I cleaned the carb for the 2nd time yesterday. Took the jets out and everything. I don't really know of any other major settings on the carb itself other than the idle adjustment. It's just a factory Mikuni carb, though. Is there another one I'm missing? Anyway, it's still doing the exact same thing and I'm just about ready to put it in the shop and let someone smarter than me figure it out. Thanks for the advice guys. I really appreciate it.

 

isnt there a low idle sqrew and a fast idle sqrew?? i've never had this problem on any of my fourwheelers but i know my ski-doo's have that problem somtimes, its not getting enough gas at higher rpms, when it is idleing try giving it a good shot of gas and see if it bogs out if it does i believe it would be the fast idle sqrew, i am not sure if it is the same with fourwheeler carbs.

 

might sound dumb, but have you changed the spark plug? same kind of thing happened with mine and that fixed it.

 

Thanks guys,
Yes, as I said in my first posting, I changed the plug. It's at the mechanic's shop now. Still waiting to hear what the problem was. Thanks for all the advice. Y'all take care.[img]i/expressions/face-icon-small-happy.gif[/img]

 

you probably didn't get your main jet set correctly then. it would be a small one that uses a standard screwdriver to adjust. you don't have to take the carb apart to set it. i think if i remember correctly it should be about 1 3/4 to 2 1/4 turns out. from being all the way in.

 

Well, it's a new one on me, but the problem was the voltage regulator. It seems if it starts going out, then you get misfires when the motor is under a heavier strain, i.e., higher gear ratios like 3rd on up. Anyway thanks for the attempts to help fix the problem guys. It's duck season and you can find me on the lake! Be safe.[img]i/expressions/face-icon-small-wink.gif[/img]

 

Back in the shop again! Has to have a whole new wiring harness do to corrosion from the voltage regulator overcharging. If it ain't one thing, it's another!