so i've been having all the same problems everyone else has been. I took my quad to the shop three times, and they said they fixed it, but it still ran like crap; even worse after the second trip. So I had some buddies work on it, and they got it to sort of run, but it still is hard to start and won't idle, so I was curious how to check the timing and where I can get an instructional manual. Any ideas??

 

I had the same problems with my 2006 650 brute force. It used to start with a little throttle just fine and run all day but i noticed that the valves were out of adjustment just by the noise they were making. I brought it to the dealer for an adjustment and thats when the trouble started. It wasn't that hard to start but it wouldn't stay going and every time it shut off it took longer to get it going again. On the third trip they finally cleaned and adjusted the carbs and readjusted the valves for the third time and it works like a top. however... i'm noticing that it is wanting to shut off before it is fully warm. but that could have something to do with the cold damp weather here in Newfoundland... it likes to get down around -30 celcius with the wind sometimes and i'm using it for plowing snow.

 

It' almost certainly one of the idle jets plugged - which is very common if you use ethanol gas. Remove the carburetor bowl and unscrew the idle jet (long skinny brass jet with tiny hole through middle and crossholes). Using a single wire from a wire brush rod out the hole. If it's bad, you may have to soak it or even replace it. Push through the crossholes, too. Adjust the valves while you're at it since you will have removed most of the stuff in the way. Replace the plugs. If the carb bowls have trash in them you'll need to thoroughly clean the whole fuel system. ATV engines are super sensitive to fuel quality - only clean, non-ethanol! These motors will start on the first turn and are not cold natured when everything is right.

 

I just discovered this revived old thread. Mine takes a while to warm up and then runs fine. I choke it to get it started and once it starts, I turn the choke off and give it light throttle a few seconds at time until it warms up. It purrs like a kitten once it warms up. From some of the posts I have read, I'll stick to the old saying of if it ain't broke, don't fix it. Yes, you can't start it up and drive off immediately like an efi model but I've experienced that with every carb atv I've ever owned. First start of the day just takes some patience. Give it about a minute and a half to warm up and you're good to go.

 

I have a 2007 650 BF that I bought in March. I rode it 3 time and it ran great. The last time
We stopped about halfway thru our ride and it didn't want to start for nothing but it finally
did. Ran great the rest of my ride that evening. I parked that night and the next I was gonna
ride it wouldn't start!! Actually it hasn't started since. I took the carb apart and cleaned,
changed the plugs had a couple buddies look at it. The last guy said it was blowing when
it should be sucking when he checked the compression! I'm at my witts end with it...please help!!

 

First thing with a non starting engine is check for sparks. If you have good sparks and new plugs and it still won't start, re-check the carbs, make sure you can see through the jets, and it is all too easy to re-assemble them wrong if unfamiliar with them. Next check compression, if low on one cylinder it could be valve adjustment, low on both, probably either wear, though this doesn't come on suddenly, or a partial seizure. Either way, adjust the valves and, if that doesn't bring compression up, strip the top end of the engine to find the fault. If compression is OK, check valve timing in case it has jumped a tooth or two. If it has you will need to find out why, stretched chain, or faulty tensioner.