# Reviving a 2003 Prairie 650



## Sarge69 (Oct 3, 2013)

I am restoring this old Kaw to good riding shape.
Fresh fuel oil and filters
Starts and idles very good
New Dynatek cdi unit
No flashing lights
both carb slides open correctly with throttle advance
However it is a little slow to rev up when warm. It will finally rev high but just is not right. The exhaust sound is not powerful and just doesn't sound right. Both cylinders are running and carbs synced with vacuum gauges.
Moving the choke lever to about half on makes it run a lot better and sound better. This tells me it is probably running lean. Where should I start looking for this problem ?
Thanks Bunches Sarge in North Texas


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## NMKawierider (Apr 11, 2009)

As with all Kawasaki's, start with the valves. Get all those set properly first.


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## Sarge69 (Oct 3, 2013)

Just finished doing as u advised and set all valves by the book,no change. With the airbox and hoses disconnected could this cause a vacuum opening and allow the engine to run lean ?


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## johnny ukelele (Oct 12, 2016)

You have to run with air filter in and lid on or you will be getting too much air...causing it to be lean...did you dismount carbs from the bike??


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## Sarge69 (Oct 3, 2013)

*2003 P650 refurb*

Johnny,
No I did not remove the carbs from the engine.
It just starts and idles great. Then when u advance the throttle it stumbles and coughs and maybe revs up slowly and without normal power. Moving the choke to about halfway on will improve things very much for the rev problems but ruin the good idle.
Thanks, Sarge


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## NMKawierider (Apr 11, 2009)

Sounds lean. Just need to find out why.


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## johnny ukelele (Oct 12, 2016)

Yes, I agree...sounds lean....so, that means, not enough fuel, or too much air,or both...you say that you are reviving the bike...how long did the bike sit up, not in service...sounds to me like the carbs need a good cleaning...do you have the service manual for the bike sarge? Its really not a hard job, but ya do need to take your time with the entire job...I was jetting mine last weekend, and must have taken mine off around 7 times to change jets...I can take em off, change jets, and back on, in about 45 minutes....BUT....lets start with the easy things first...did you put a new set of spark plugs in the bike....properly gapped....blow holes out with compressor...make sure they are clean before ya pull the plugs....otherwise all the dirt will fall into your motor after you pull the plugs out.....

---------- Post added at 08:55 PM ---------- Previous post was at 08:43 PM ----------

Sarge...the choke on these bikes, actually isn't a choke...per say....
It is actually an enrichener....when you move the lever on the handlebars, it actually pulls a cable, that splits into two cables, and pulls a plunger in each carburetor, which opens a circuit in each carb to give them a little more fuel...thats why it is helping the bike run better above idle...
Ask any questions...I do not mind explaining anything you don't understand
...

Sincerely.....johnny

---------- Post added at 09:03 PM ---------- Previous post was at 08:55 PM ----------

Here is a pic of my carbs with the bowls off last weekend...


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## johnny ukelele (Oct 12, 2016)

Oh...I forgot to ask about your tool collection also...sometime I take it for granted that everybody has a phillips screwdriver that is two feet long...


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## Sarge69 (Oct 3, 2013)

*Thanks Johnny*

If the carbs are enriched by fuel and not chocked by a butterfly plate why cany I just run her with the choke on ?
#2 Instead of a pesky tiny washer to raise the needle why not take .040 off the bottom of the needle ?


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## NMKawierider (Apr 11, 2009)

1. The choke is a port straight to the bowel so its raw fuel to the intake port.
2. Shortening the needle won't change the needle taper above so fuel to air ratio won't change as the CV slide advances. You want to advance the needle to port so it get more fuel with the same air.


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## johnny ukelele (Oct 12, 2016)

Ok...here goes...I always try to do the easiest things first....but go at it, as you feel comfortable...do you know how long ago it was when it did run good, and what has changed since then....or how long did it set up??

List of things to check...

Spark plugs (gas fouled from too much enrichener?)
Spark plugs gapped correctly
Airbox snorkel (make sure there is not a dirt dobber nest restricting or blocking the snorkel)
Rubber intake manifolds cracked (spray brake cleaner or carb cleaner at intakes while motor is running, listen for change in motor....)
Cracks in spark plug wires (run at night and look for sparks flying)

I will keep adding things as I think of more....


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