New member here. Just bought a used 03 Pairie 650 for $2000. Looked for a long time for a decent machine and found this one to be in decent shape and I really like what I read about the V-Twins. It runs out well, everything works with the exception of it is locked in 4x4. The KEBS/Acuator problem.

Biggest issue is popping back through carb. Done a ton of reasearch on the web on this and here's what I'm thinking. Would like you guys to give me your opinion.

I played with the pilot adjustment and it improved a bit. It will run perfect on about half chocke. This indicates it's running lean.

I pulled the covers and the carbs are very dirty. I plan on tearing them down and cleaning them.

I've read were these carbs were set up lean from the factory. I see where many have added washers to the needles to move them up or installed aftermarket adjustable needles. Thing is this is a low RPM problem which indicates a pilot issue rather than a fuel issue in upper range.

Is is a good idea to put larger pilot jets in?

Any comments would be appreciated. Thanks

 

If you're running at sea level, then larger pilots may be ok if that is what everyone is doing because you may end up buying new ones anyway if they are blocked.

I'm thinking a good cleaning is sufficient. Just make sure you get cleaner, carb spray, whatever to come out all the little orifices and little pin holes that are in the carb throat.

Avoid just putting whole carb in a can of carb cleaner unless you know what you're doing because there may be seals or o-rings hidden from view that get damaged.

 

Until you clean the carbs I wouldn't recommend attempting anything else.

As to being locked in 4x4 have you checked to see if the actuator itself is the problem or if you have a wiring or fuse issue?

 

I am a tech and I found that adjusting the sync of the carbs can help as well as raising the needles and adjusting the fuel screws to achieve the best idle.Only when its a lean problem like stated above.

 

Very interesting post...took me a while to find myself there, but motorcycle and SU carbs on British sports cars years ago finally forced me to check the carb sync...here is what I posted on KawiRiders:

I pulled my carbs this weekend and cleaned them due to a backfiring condition at idle.

Front cylinder carb was dirty. Cleaned both well and ran small hobby drill bits through all holes by hand. These are hobby drills I bought for opening jet sizes on my Honda.

First I was suprised at how much work it was to get these carbs off and on the bench. Wow is all I can say. I suppose next time it will be easier since I did it now.

A few observations. It's crazy hard to get at different screw points. Particularly the clamps on the manifold hoses. Took forever to get them positioned so I could get a screw driver in there.

I put the airbox base on without the air cleaner and cover in place to tune the pilots, set idle etc. Then found that it ran different once the cleaner was in place.

After all the work I still had some spitting back in the front carb. I decided to adjust the vacuum sync and low and behold it was off. I adjusted the sync and the engine came alive. They won't run very good if one carb is pulling more than the other.

I then went back and reset the pilot settings and it runs like a dream now. Idles perfect, no backfiring and quick throttle response.

I will say this about the pilot settings. Number of turns is sort of a misnomer. My manual on the Prairie 650 says 2 1/4 turns. On most engines these recommendations are based on carb tear down and are to get you in the ball park. You can turn the screws in until you get a reduction in idle speed (about 1+ turn out) and then adjust about 1/2 turn out from there to get the point were pilot is "fueling" the carb. Then engine response will tell you if you need more or less fuel to maintain idle and get response from engine. I found a richer setting worked better. Mine are probably at about 3 turns out.

Until I got the carbs sync right the pilot setting really didn't have much effect.

 

Sounds like you got it. Just be careful with the fuel screws,alot of times when you turn your fuel screw out 3 turns or more,The small spring that is on the fuel screw holds tension on it, so it doesn't backout from the engine vibration,heat cycles etc, isn't very long and doesn't hold tension on the screw so it falls out. A little spot of silicone rtv over the screw can keep the screw from falling out and getting lost.

 

Where is the vacuum sync on the 650 prairie?I have a 2002 that is spitting back through the carbs at low-med. RPM.