So have you been able to solve your starting problem? I am haveing the same thing happen with my 2006 650i. It actually started better when it was colder out. Now that it is in the 40's it seems that the choke is too much and giveing it some gas is not enough. Last night after cranking on it for an hour and using every possible combination of choke and throttle I finally managed to get it to start. After the raw gas cleared out and it warmed up it ran great. I drove it around for a half hour then parked it in the garage. Now this morning I ran the battery down again and it won't start. It acts like it wants to start and will backfire ocassionally. I pulled the front plug and it is wet with gas. The last time I changed plugs I put in Autolite so I am going to go find some NGK's today and see if that helps. I just ordered the Dynatek CDI unit this morning also because it is supposed to give a hotter spark and fix the timing offset. I was wondering if maybe this offset is contributing to the hard starting on Brute Forces? If anyone has ran into this problem and can tell me what they did to fix it I would be all ears.


<div class="FTQUOTE"><begin quote>Originally posted by: jhb211221

Yes,

That is the only way I can get it to start. I always try to start it choke off first, then go to choke on, and then push the throttle if need be. Here lately the only way I can get it to start is to open the choke, and mash throttle. I spent 1 hour trying to start this damn thing Sunday. We drained the ATV Battery, and another, changed plugs twice, (each time the plugs were damp with fuel) and then resorted to jump starting it from another ATV. We finally got it going, but it did take 1 hour, it was very cold out about 28-30 degrees. Once it started and got warmed up it ran really well all day, and always restarted fine. Once I trailered it home, (about a 30 minute drive) I could not get it to start, gave up and pushed it in the garage.</end quote></div>

 

OK I am still having cold start problems. I decided to remove the carbs and check what the previous owner had in the way of jets. I found a 150 in the front and a 155 in the rear. The mixture screws were only out 2 turns so I set them at 2.5 turns. I checked the needle valves and they don't seem to be stock. They are tapered and have a clip. I thought the stock ones had a straight shaft? The clip was in the 4th groove from the end and had 2 washers on top of that. I thought you were suposed to place the spacers under the clip to hold it up when it was fully seated? Anyway I am going to leave the carb off until I can get the stock needle valves and then start jetting from scratch. Does this sound like I am on the right track?

 

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OK I think I have this thing figured out finally. I bought the stock needle and jets and put them in the carbs and set the mixture screw out 2.5 turns. After I put everything back together it still wouldn't start by cranking with the starter. I then switched to the pull starter and it started on the third pull. [img]i/expressions/face-icon-small-confused.gif[/img]
A couple years back I had 1977 Kawasaki 650Z and it would not start unless you turned the lights off to save juice for the ignition. Evidentally the spark was weak.
I put a Dynatek CDI in the Brute Force and now it starts right up every time! It must be a combination of the hotter spark and over riding the 6 degree offset that Kawasaki builds into the stock CDI.
Perhaps if Kawasaki wouldn't muck up their timing on purpose they wouldn't have such a bad reputation for having hard to start Brute Forces! I almost bought a Grizzly instead of the BF 650i just because they tend to start when you want them to.
Now I have to go back and see if my jetting changes didn't cause a new problem! [img]i/expressions/face-icon-small-frown.gif[/img]

 

OK I finally got things right! The Dynatek CDI didn't fix my starting problem after all but setting the valves did. Seems they were too tight to close all the way at low speed RPMs especially with the automatic compression release. The Brute starts right up now at the first press of the starter button. The Dynatek does make it a lot snappier on the throttle. It will bring the front end up anytime you blip the throttle. I'm just glad to have it running again. If anyone else begins to have starting problems and it has been 500 miles or more since you checked the valves than I would start there.

 

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[img]i/expressions/beer.gif[/img] sorry about that last one.
so, i have 2 bf 650s. 2005,2006. 05 starts great, 06 starts like crap and getting worse since cold weather.(20s-40s). did everything mentioned above before searching for help, surprised about all the others w/ problems. down to adjusting valves. how do i do this????? i'm afraid this is above me. any help would be great, with some guidance i think i can do it.

 

Valves are easy to adjust. Have you downloaded the manual for the 750 Brute Force? The procedure is the same for a 650 as in the 750 manual. Intake valves are set to .15mm and the exhausts are set to .25mm.
1. remove the left side plastic, Battery and tray, and tin tray under the electronics.
2. remove the pull starter housing.
3. remove the plug covering the inspection hole for top-dead-center.
4 remove the rear valve cover being careful not to lose the rubber o-ring.
5 place a large socket over the nut where the pull starter was and rotate the crankshaft counterclockwise while watching the rear valves open and close until you see I-R (which is a sideways T and a R), both the intake and exhaust valves should be closed and the top of the sideways T should be lined up with the notch in the inspection hole to be at Top_Dead_Center. Be aware that the mark comes around twice per firing cycle but it is only at TDC when both valves are closed.
6. Loosen the locking nuts on the intake valves (which are the valves closest to the carbs) and use a screwdriver to turn the adjuster screw until they are a 1/4 turn out from contacting the valve. Hold the screw in place and tighten the locknut. Do that for the other intake valve next to it. You can check the clearance with a guage but for me a 1/4 turn out has always been just right.
7. Do the same for the rear exhaust valves except turn them out 1/2 turn from contact.
8. replace the rear valve cover making sure to keep the o-ring in the groove, a little grease helps.
9. remove the front valve cover and repeat the process watching the valves as you rotate the crankshaft counter clockwise. Look for the valves to all be closed at the same time as the top of the T (of sideways TF) lines up with the notch in the timing inspection hole.
10. set the front valves one at a time, 1/4 turn out for the intakes, and 1/2 turn out for the exhausts.
11. replace the front valve cover, timing hole cover, recoil starter, battery tray and battery, and side cover
12. start and enjoy the improved performance.

 

thanks dude. allready adjusted the valves. starts better than when i first bought it. got the info through another thread. only been a member of this site for a month or less and saved a crapload of cash allready. gotta love america.

 

Need suggestions. After about 2 years of using my 2006 650 BF 4x4, I started having problems starting it. I don't use too much. I have approximately 500 miles on it. Anyway, it was working in a weird manner, until it finally couldn't get it to start. The only way to make it stay on was have it choked at all times. The instant that I would move the lever to the opposite side, it would die. Again, it would start only if choke lever all the way to the left. I know that's not normal operation. When I crank to start it, it attempts to start, but it doesn't. I'm suspecting that it might be the gas filter or the carbs are simply dirty. The manual that came with it is not very helpful when it comes to troubleshooting. I will certainly appreciate any assistance from you all. I want to attempt to figure out the problem on my own before I decide to take it in. Thanks.

 

curious, when you get it running, once it warms up does it run fine? does it start ok then?............. or can't you even get it started at all?