TOPIC:

Thanks Neville & Scotch. You both gave me some good things to think about. 


#1. I've messed with the Fast-Idle Cam roller before. I'm not sure I've got it quite right, so I'll try to make sure I've got it set up correctly. 
#2. A better battery and starter makes sense.

P.S. After switching the starter between my good running Kz1300 and my poorly starting Kz1300, the 'hot starting' problem seemed to move to the good running Kz1300. It absolutely didn't want to start when hot, where I never had an issue with it before, so the starter being part of the issue makes a lot of sense.

I had years of hot start issues on mine - if I stopped I would have to wait 20 minutes before it would start.  On examination of the started windings it "looked" like the insulation was breaking down and there were signs of scorching to the body through the card/plastic insulators (it's been a while)

I bit the bullet and bought a "Ricks" started motor - VERY expensive but worth every penny. The power cable attaches in a different position which makes it really awkward to fit but worth the struggle.

old: www.facebook.com/david.field.98/videos/798270944791217/
new: www.facebook.com/david.field.98/videos/506435414627656/

Hi there Zed 13.
Please drop me an email at This email address is being protected from spambots. You need JavaScript enabled to view it.. I would like to catch up seeing you live down the road.
chrs
Bruce

I decided to try the Rick's starter on my 1979 Kz1300, since the old starter clearly had issues. After spending most of the morning trying to get the terminal wire switched around (Rick's is on the back of the starter, the OEM one's are on the front), I finally got a chance to try turning it over with the new starter in place. The bike had been sitting for a couple of days, so I wasn't actually expecting it to fire. I just wanted to make sure the starter was going to turn over at all.

I turned on the gas, pulled the choke up, and hit the start button. Wow!! Amazing!!!  It started up right away. No starting fluid or gas in the air intake needed. I barely hit the start button and it fired!

I'm to tired from all the crawling around to do try much else, but I'll give it a through test later this afternoon. It's supposed to be near 90 F today so I'll try starting it once it's good and hot. I'll let everyone know the results, but so far, so good!!






 

One has to realize that the ignition circuit when using a ballast resistor draws the battery voltage going to the coils down to around 8.7 volts. If the starter on your bike is drawing higher amperage than it should, it will draw the battery voltage down to between 7 and 8 volts. then the ballast resistor does its job and will reduce that 7-8 volts down even further probably to the point that the coils are unable to create a spark.

A strong battery is paramount. A clean power feed to the starter is really important and finally a starter with low draw is important. Marginal battery or starter relay or a starter needing cleaning of the commutator rings  brushes replaced and your into a situation like what you describe. It's a big displacement engine looking for 140 amps to turn over and the ignition circuit is looking for another 8-10 amps. Add in a headlight that comes on for daytime running lights - another 7-8 amps. it all adds up. Then you can also add in a few marginal switches in the circuits turned on and count on another 5-10 amps of inadvertent draw. It's a 40 year old bike and depending on how it was used / stored, it may need more attention to make right.

Glad to hear you're pointed in the right direction.

As it stands currently - using a piece of 1/8" brass tube or a formal Jet (Holley) as a restrictor is a compromise.  StanG was one of the first to make this adaption and he noted that the engine started significantly quicker but there was some choke-lever jockeying required until the idle circuits were charged and delivering fuel, equally.
I've subsequently enlarged the restrictor and have found it to be equally effective in getting choke fuel into the cylinders and the "Jockeying" has been reduced but each engine and how it's set-up overall will dictate how any changes will affect this choke-lever issue and that's where some experimentation is required.
The whole (factory) choke set-up is wonky in my opinion.  To much fuel and air (throttle-plate gap) has the RPM's outrageously high when the roller is on the apex of the cam and reducing the choke has always previously seemed to lead to the engine quitting because of a now disproportionate amount of fuel/air when an attempt to reduce the choke is made.  That's where the "jockeying" comes in.
I have  modified the fast-idle cam profile on my 2 operating sets of carbs.    It's done relatively easily with a Dremel and stone, with the carbs on the bike.  It just requires that the cam be moved over (and retightened) against the choke rod support for access.
But:  I won't advocate this because once the fast-idle cam profile has been changed it will be very difficult if not impossible for most, to return the profile to that of the original if the re-profiling doesn't work.  And: Changing the profile would be considered tedious by most because it requires gradual changes to the apex,  one change at a time - one cold start (one per day) at a time. It required three days / 3 cold starts before I got the profile to a point where the choke management was a lot better. 

One thing for certain: If a choke air restrictor isn't working to your satisfaction.....it's completely reversible with no harm done.