I just got this ride the other week it seems to be a very simple machine comparred to my 07 honda rincon. I actually think I like the big bear better for muddin. I am haveing a small issue don't know where to start if I start it up which it runs great starts easy everything seems to be in good working order. If I let it sit still and idle for say 15 20 mins the idle will start to rise higher and higher. If I get on it ride it around for a min and park it it will idle at the correct speed again until it sits idleing for the same amount of time it will start to rise again. What's the deal is it just cause it gets warm sitting still

 

Does engine ever die or stop running? If engine just speeds up BUT doesn't stop than I would clean carb real good, Adjust the mixture correct, check the carb. intake boot for leaks or cracks that could cause an air leak!!!!!

 

No the engine never dies it starts up real easy with just a little throttle and will run all day long normally unless you let it sit and idle for extended time then it slowly will rev up not sporadically but smooth rpms just get higher and higher.

 

I would locate the fuel mixture screw on carb! Most of them on this bike is on the bottom side of carb vertically.Look at carb float bowl[has four screws that holds the bowl to carb, just look for an curved bend in the molding of bowl] if the cap has been removed then the mixture screw is inside of an molded nipple turn out bout 1 and half turns[counter clockwise]. If you can't find it send us an picture with your phone an we will go from there...

 

Why does it sit and idle for 15-20 minutes? You could always shut it off and start it again when you are ready to ride again! The quad is probably heating up just sitting there at idle...does the fan run during that time? I have an 08 400 and it has never just idled up like that, but it never sat and idled more than a couple minutes at max! How many miles on the quad? When was a general service done (valves checked, fluids changed...)? Does the reverse light ever flash when it idles up like that?? That is a sign that it is idling too high...

 

Well it will run slow or idle alot when my wife rides it that is how I first noticed it was we were trail rideing a hilly trail she was going slow and stoped at the bottom till I got to the top and walked down to get here up I noticed it idlesing high I ran it around for a minute and it idled fine it seems to do it when air is not moving across it to keepp it cool. It has around 1200 miles on it the service is freash I just got the quad a couple weeks ago the guy was a amsoil dealer and said he stayed on top of it pretty good. I think maybe a carb vent could be clogged or maybe just the ambient heat is vaporizing the fuel is it possible

 

Does the fan run while it is idling like this? I have never heard of any other quad that does this...the machine is so simple that it seems like if it was going to idle high, it would do it all the time. I don't want to insult or anything but it isn't just the extra noise of the fan running is it? If it isn't affecting the way anything else works, i wouldnt be too concerned about it...but would still be nice yo know what is going on!!

 

No it isn't the fan running but it does kick on when it gets warm I haven't noticed for sure but I have seen the red light blink. It is odd it idles perfect unless you let it sit still for a period of time my dad put 60 miles on it when I first got it no pproblems but he rode it my wife dosent ride very aggresively because she is just learning. I would like to just figure out because it isn't right but who knows.

 

If you have a reputable Yamaha dealer around it may be worth shooting them an email and asking if they know what would be causing it...I know sounds strange that they would help through an email. When I bought my old wolverine years ago I pulled the hubs off to change front wheel bearings and parts just started falling out. It was very hard to get old wheel bearings out without any inside races left. I emailed two dealerships asking what the secret was and both emailed me back later that day yet. May be worth a shot...

As far as the reverse light flashing...that is the indicator that the idle is too high. Mine only flashed when choke was left on too long...and at one point I had a broken speedo cable so speedo was reading zero but quad engine was revving. Bike thought engine was revving but not moving...new speedo cable and all was good! Good luck with getting to the bottom and post back with any findings!!

 

Yeah as soon as I get to the bottom of this I will post it up that's for sure