Well, where do I start without offending and sounding know it all smart-ass while I really know nothing beyond real life experience.
The cold, hot, whatever, KZ1300 start problems have been a prominent theme. Here is what I found. The KZ is a fuel ethanol free era bike. Most likely, a leaded fuel era. What does it mean? Negative effects of ethanol lingering in every crevice of the fuel system using current pumps, especially the very sensitive crucial parts in the carburetor. Led also 'lubricates' parts, but let's just forget it now. But anyone would wonder why racing fuels are full of friendly led? Well, at least the two strokes.
The 1980's. Honda Goldwing GL1100, 1983. Then the KZ1300 1982. Fair to say same era? Whatever carburetor and fuel delivery particulars, I'd safely assume all made successfully in their own might for the same gasoline - by coincidence ethanol free. A pure gasoline, right?
So, I ran on regular 87 octane with up to 10%, sometimes 15, gas. On the Honda. Ran great. But not long enough. Started with coughing eventually, ended with running on 2 or 3 cylinders and a hell of a rattle and shake when starting it! Just awful. Up to the point where I couldn't start it. I bought a new carburetor rack, obviously. But before changing the hardware, I filled the tank with ethanol free gasoline. Instant improvement. It took about 2 months maybe before those annoyances of rattling and disturbing start ups went away. Sunshine, hot traffic, zero and negative temperatures, whatever - NEVER had a start up problem, NEVER misfire, NEVER running on any but all four cylinders.
Now, fast forward one year of happy riding and crisp throttle response - EVERY time. I filled up the tank with the regular 10% ethanol containing 87 Octane, or whatever the actual ethanol containing gasoline. One tank! The engine spoke back to me right away. Not Happy!!! Less power, rpm's went up by 10%, irregular idle, trouble with smooth start up. Let it sit for a couple days. Start up: running on 3 only cylinders again. Difficult to eventually having it smooth - just rough idle and sometimes one, sometimes two cylinders missing!!! Noticeable less power on the road. Fast forward again a few days, and another fill up with 87 ethanol gas. Just started up the engine. Running on two, 2 (!!!!!) cylinders, then 3, then 4, then 3, and so it goes. 15 minutes of gasoline smell, shaking, roughness, and stalling engine!!!! Coincidence? I say.... - NOT!!!!
I don't want to go on too much about this, as my mind is clearly made up. With all due respect to the more knowledgeable than me and professional, while it might be a half assed good solution, I religiously believe ethanol completely free fuel is the only way to have these bikes run correct. My KZ starts at the very press of the button - after sitting for a week in a cold outside garage. No hesitation. In the meantime, the Goldwing is still fucked despite filling it with ethanol free at 3/4 empty. It will take time, but I know - never putting ethanol containing gasoline in this bike will get it back the way I got used to on the road again.
Gasoline is flipping expensive here in Vancouver, BC. Especially the ethanol free. I just paid $30.71 for a 17.36 liter fill up. That's what used to be filling up a frigging car!!!
Sick. But what can I do? I am the owner and keeper of this bike, and the bike deserves all the best care from me it needs. No cheeping out on delaying oil changes, and this ridiculously expensive gasoline - cheaper than having a couple of kids. So let it be. No 360 gas treatments, no gimmicks. Nothing will go inside the tank of this bike except ethanol free fuel. Unless absolutely no choice. Ditto.