Won't cold start 19/20, runs perfect otherwise

My 77 Z650B1 UK Import takes several hours to start when it is cold (this includes time to recharge the battery and try again).

I have been racking my brain on this one - reading and re-reading the Factory Service Manual.

Bike has Kerker 4-1, Points Ignition, B7ES plugs with 5kohm caps, no-name Pods. Carbs had both pilot and air screws, so when the bike did start, I tuned them all for maximum idle - it was a pain. However, once tuned, it ran like a dream, passing all the tests:
- once warm - idles smoothly with no choke
- runs from idle to 1/4 throttle perfectly
- 1/4 throttle to 1/2 throttle response is perfect
- 1/2 throttle to full throttle is downright frightening
- ALl plugs are always perfectly tan
- starts warm without choke, 1st kick.

I rebuilt the carbs and have taken them apart a few times to clean out the starter circuit and pilot circuits. Mains are 115, pilots 17.5, needles at clip #4 (second from bottom).

So it all sounds so perfect, I can't figure out why she doesn't want to start when cold. I am running without lights for max voltage, kicking like crazy.

The only possibility is the battery, which was unused but charged monthly for the past year. My latest crazy idea is that full choke is too much for it, and I am flooding it without realizing it. It is presently about 40 degrees F here. (5-7degC)

Other crazy ideas?

Inline, this is a shot in the dark. If the throttles are not fully closed this negates the chokes which are just enricher valves are'nt they. Try turning your idle screw down a touch and making sure your throttle is dead closed before cranking.

almost sounds like one or two choke wells are plugged. have you blown carb cleaner through them to be sure?

fixer5000 wrote:

almost sounds like one or two choke wells are plugged. have you blown carb cleaner through them to be sure?

This is what I was thinking also. But do yourself a favor, save your pennies and ditch the points for a Dyna S. After installing mine, the bike starts 10 times faster and easier!! It's running almost before my finger is off the start button! Also do the WG coil mod (if not already done) and think about a Battery Tender which works awesome.

Thanks for the suggestions, I found the 2 wires to the kill switch had some insulation cut due to the holes in the handlebar where the wires go in. An intermittent short there blew fuses (fortunately not while riding) before I tracked it down, but may have also affected the power to the ignition and starting system.

We'll see if this is the culprit after an overnight soak.