2006 Brute Force 650. The bike ran pretty good when I first brought it home. Since it's gotten colder it really runs like crap. It wants the choke on all the time.. Seems pretty cut and dry.. It's lean, change the jets. Well I did. I went from a 139 front and 142 rear to 142.5 front and 145 rear. It seem to run a little better at idle however now it runs like crap up top, the only place it seems to run better is in the middle. It's still pretty much unacceptable at idle. I'm not sure where to do from here.


Modified stock exhaust
Modified air box
CDI

Other than that the bike is dead stock. I fooled with the pilots too but it did not seem to really do much.

Any suggestions.

 

Well up top it would seem like its too rich. You might try going back down on the 145. Also try adjusting your mixture. Just do a quarter turn at a time. Your going to have to play with it. Getting it right might take time.

 

take it back to your dealer, let him dail it in.

 

I'm no Brute mechanic but there have been similar posts in the Kawi forum. Maybe if you repost this there you will find a specific answer. Seems the prior posts often ended up that a valve adjustment was needed.

 

Is your warranty already expired on that bike? Sounds a little fishy on an atv that new. I'd take it back to the dealer after I got everything back to factory specs.

 

i would doubt the dealer would fix this under warranty if you have modified it. try to put your air box back to stock as i think they run lean from the factory. my bud has an 06 650 and hasnt mentioned any problems w/ his but other friend had an 05 750 and it ran lean to the point of back fireing some times and they put differnt jets in them.

 

i'd guess you have to go bigger yet on the jets. i have the 650i and it has 155 jets in front and rear. i live at about 4500 feet, but if i lived at a lower elevation, i'd have to go bigger yet.

monty

 

I have 145back 150front in it now. It runs better. I am putting a 45 pilot in. That will fix it I have every confidence. It wants fuel.

 

did you do the WD40 or either test to see if its sucking air? I know a lot of people overlook the simple problems

 

My bf750 was doing almost the same thing. I put it in the shop 3 times and it never got better. This last week they installed a moose ignition module and a jet kit. Now it runs great and starts up right away with very little warm up time. The throttle response is even better and seems faster.