TOPIC:

OK, wise ones, I need your help again. I didn't know whether to post this in fuel or electrical issues, because it might be either . . .

After I've ridden as a little as a half mile, my KZ1300 won't immediately start again after I shut it off. It will crank, but not start. Two things will get it to start -- a squirt of starter fluid, or waiting 15 minutes.

I don't think the problem is vapor lock -- my fuel line is short and has no "uphill" sections, and the bike doesn't have to be hot -- just warm. I'm suspecting that either the bike is flooding somehow, or I have an electrical component (coil?) that's going bad.

I wouldn't think one malfunction out of six float valves would keep the engine from starting, but a stuck float/bad valve is a possibility since my crankcase recently filled with gas when I forgot to shut off the petcock . . .

I'm leaning toward an electrical problem. Other than this annoying problem, the bike runs fine.

Your thoughts?

The Starter fluid trick would lead me to believe your struggling with a fuel problem. I wouldn't let the float level issue hang around too long. You're lucky if only your crankcase got filled with gas. Lucien Harpness is changing out a bent connecting rod because his bike got hydraulically locked with gas in the cylinder.

Starting fluid - bad bad bad. It washes the lubricant off of the cylinder walls and then you're metal on metal. I've also seen cars coming into the dealership on the tow truck wreaking of ether and no compression. We managed to save them by squirting oil down the cylinders and flushing out the crank case and a new oil change.
One mechanic had a car come in with the "too much ether problem" and finally got the car started only to have an explosion. The ether in the crankcase exploded and blew the oil pan right off the block.

Sometimes if a vehicle will run on ether but won't stay running it can indicate a weak spark or fouled plugs because ether is so volatile it doesn't take much to light it off. But in your case, once it's fired up it runs so that leads me to believe you're not dealing with a spark issue.

If the problem was a weak electrical component affected by heat, wouldn't even a weak spark ignite the starter fluid (and start the bike) because of its higher volatility?

For now, I'll try shutting off the petcock every time I turn the bike off to see if that helps. The bike was just tuned last summer (the difficult restart problem began a couple months later), so I'm hesitant to pull the carbs for clean/rebuild and end up having to pay for yet another tune/sync.

Can I drop the carb bowls while they're on the bike and check the floats/valves? Sounds tricky -- like I'd need to use a mirror . . .

You should do the wet float test by placing clear tubing on the drain pipe on the bottom of the carb bowls and having the rest of the tube up against the side of the carb bowl. Then open the drain screw.That way you can see where the floats are set. If one of the float needles is passing the float reading will be high and keep creeping up until it's higher than the carb throat.

Thanks -- I'll try that. That is, if spring ever comes -- the garage is way too cold for now. I forgot that there are only three bowls/floats/valves, not six. Maybe if one third of the cylinders are flooded, it would indeed prevent a start . . .

I braved the cold to take a peek at my carbs. They don't have an overflow tube. There's a little tit hanging down from the front of the bowl that looks like it might have been an overflow on previous models, but mine are blanked off -- no hole. Too bad -- an overflow tube probably would have prevented my flooding problems in the first place. Seems like a poor design . . .