Cannot ride off till engine warm....10 mins

I don't think Kawasaki would have sold my KZ650 with this problem ?, looking on other sites it seems I am not alone. She starts perfect the plugs are spot on and once warm rides a dream, but from cold I simply cannot ride off till about 10 mins has passed she just won't pull away and just bogs down.....?
Choke seems to work fine she screams away pulling it up and I slowly drop it down over several minutes but seems impossible to ride her till she warmed fully?
What's the solution please ?

One step larger pilot could help.
Steve

Shimming needles may also help. That is if it idles fine, but bogs down when you give it gas.

60/40 test.
Cover half the airbox with duct tape.
Drive
Is it better?
If not then take off the tape.
Then crack the airbox open slightly.
Drive.
Is it better?
At least this will help you narrow down your issue.

Sounds like dirty carbs restricting fuel flow.  A full tear down and clean out of all the internal passages, along with replacing all the various O-rings, will go a long way towards getting your bike running smooth.

wrote:

Sounds like dirty carbs restricting fuel flow.  A full tear down and clean out of all the internal passages, along with replacing all the various O-rings, will go a long way towards getting your bike running smooth.

I agree. Cold engines need more fuel. Hot engines can run on a leaner ratio. I’d be looking at cleaning the carbs. It can never hurt, always time/money well spent. Could be in the enricher (choke) or the pilot circuits. 

Seems like your situation is more severe than mine. My KZ900 will still bog down after a 20-30 second half choke warm up but only takes riding about 3-4 blocks away until its warm and it goes away. I have air pods with air corrector jets installed. Maybe my air correctors need to be tuned or maybe I should lift the needle 1 groove?

If I remember correctly you have a B3 model.  If it was a US market bike then it should have an accelerator pump and was jetted rather lean.  If it was a non US market bike it will not have the pump and is jetted not as lean.  If it is a US bike and the pump is not functioning correctly I can see how it might take longer before it will run correctly as it heats up. 

Yes she’s a B3 I’ll look into the pump I’m very reluctant to pull the carbs on a whim specially as she runs beautifully starts on the button etc. It’s just the pause before riding off lol I’ll do some looking into problem thanks for the advice 
Cheers Simon 

I have been fixing up 1980's motorcycles for the past 10 years, approximately 4/year. Typically the bikes have been sitting for many years and I only pick up bikes that are 100% or nearly 100% stock. I run into this problem often, maybe 1 in 4 bikes. My solutions have been:
Adjust fuel/ air mixture screws and sync carbs for the best idle. Then open mixture screws 1 more turn.
Shim needles 0.020" at a time. Test ride and keep shimming until bog down is gone.
I know this is Jethro engineering and I am compensating for something eth that is not right, but I haven't figured out what that thing is yet.
Worn slide bore? Slide diaphragms stiff from age?

The KZ550 I bought had green gunk in the carbs. I used my smallest jet drill to clean the pilots. It started and ran like a scalded cat. Sold it too soon. 
Steve
 

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