I'm thinking about buying my brother's 86 300 Bayou. He bought it last fall and hadn't driven it at all so I decided to take it out for a test drive today. It was about 20*C outside and the bike ran so hot it was uncomfortable to drive with my right foot resting on the foot peg because of the heat. Even the side cover was so hot that water would sizzle and evaporate off it instantly. Also, once it was warmed up it wanted to idle so high that I'd have to shut it off when I put it in neutral for fear of the engine seizing. Aside from that, it works great.
Does it sound like a carburetor problem? I'm going to tear it down tomorrow and give it a good cleaning. Hopefully that will fix the problem.

 

Hey - I too have the same bike 88 however and experience the exact same problem although I'm yet to consider it a problem - well atleast the heat anyhow.

I'm trying to figure out whats going on with the idle also for me it's not only in nutural but also from time to time in gear it tends to rev out and take off on it's own.. def carb issue I'm going to be plugging into this project this weekend I'm thinking i'm sucking in air from around the intake - as I just had the carb rebuilt so I can't see it being inside my carb

but yes I to have the heat that I ride with my one leg kinds pointing out and the idle issue... be nice to see someone's feedback on this makes me feel a little better knowing it's happening to you also :P

 

Mine stays revved up in gear too, almost like having cruise control on it. I already checked for air leaks around the intake and there are none. Hopefully cleaning the carburetor will fix it.

 

double check with the real carb experts. i think if they run lean it'll raise the idle. i could be wrong. so with the heat, is your exhaust pipe glowing red? if so, richen the mixture, you're too lean! pull the spark plug, what color or discoloration is the electrode at the end? that'll tell you a lot!

 

I just cleaned the carburetor but it still seemed to be the same. However, I was able to adjust the idle lower this time when it was warm and it will still start and idle when it's cold so may have the high idling problem fixed. It was slow to come back to an idle before and now the rpms drop back down quickly like they should. Hopefully the heating problem is gone too but I won't have a chance to find out until the weekend.

 

you removed the jets and cleaned them, right? i mean, i know you said you cleaned the carburetor, but the jets must be removed to give them a thorough proper cleaning. just double checking, please don't get offended. we're trying to help.

 

I took out every part I could possibly remove and cleaned them out with a small wire and compressed air.

 

Just grabbing at straws here, but my Suzuki has 2 recommended spark plugs. 1 that is normal and 1 to use if the quad runs hot. Not sure it applies to your situation though.

 

I'm running the coolest plug I can in it already, a BR9ES.

 

I finally got the old Bayou trail legal this weekend and put about 60 miles on it in 25*C + temperatures and it seems to be working fine and doesn't get much hotter than my brother's Yamaha so I'm not too worried about it running too hot and destroying something anymore. We had it out after dark and the exhaust definitely isn't glowing red. However, it does stall occasionally at higher rpms like it's running out of gas but starts right back up and runs fine. I took the carburetor apart and cleaned it again and pulled the tank and removed the on/off/reserve valve and gave it a good cleaning but it's still doing it.