Fzr 600 woes

[Lorenzai]

Short and sweet. Bike hadn't been ridden in a few weeks, maybe a month. Last night I started it. It started hard and felt like it was running on 2 cylinders. I kept it choked and let it run until it reached operating temperature and it began to run fine. Revved it a few times and it blew a little bit of moisture and soot from the exhaust and all seemed fine. Today I go out to start it and let it run, and it won't run. It tries but it just won't light off for more than a second. It backfires very very loud sometimes and it even backfired a few seconds after I had stopped cranking it and walked away. I have no idea what's wrong! Any ideas? I'm thinking about pulling the plugs to see if they're black and if its getting fuel. I need to winterize this thing on the double and I can't put antifreeze in it and run it to get it into the block if it won't run. I thought I had plenty of time but its gone from 70s to 40s in a week here.

[Lorenzai]

The plugs were wet with fuel and a small amount of carbon. I cleaned them all up and put them back in. It ran for about 5 seconds on 1 or 2 cylinders and it was dead in the water again. Sometimes I can hear the fuel burning in the exhaust or something. So, I have fuel. I am thinking something ignition has gone sour. I'm going to replace the voltage when I get a chance, but I don't expect any change there.

[DonTZ125]

Sounds like crap in the carbs from bad fuel, or rust in the tank that's shaken loose.

There is no reason you can't drain the rad & engine then refill with coolant. Crank it over for a bit to help burp it; a little bit of air won't cause any difficulties. Really, for a street bike you should be running aluminum-safe antifreeze all year long.

Changing the voltage regulator won't affect anything; you aren't spinning the alternator fast enough. What voltage is your battery holding just sitting there? The ignition on these things is quite hungry, and a marginal battery will spin the crank but not have anything left for the spark plugs.

[Lorenzai]

I tore the carbs all the way down and cleaned them thoroughly with carb clean as well as 120psi air. The rusty fuel tank was replaced as well, with one that has no rust at all. It has a new oversized fuel filter as well. The plugs are getting quite wet and I can smell gas so I know it isn't fuel delivery. The battery WAS at 12.8V before all the attempts to get it started. I tried jumpering it to my car battery (not running) to help give the ignition some extra juice but there is no difference. I'm just kind of at a loss. What goes bad sitting overnight while not running?

[Lorenzai]

I decided to recheck the spark plugs. Back to the basics before I start throwing money at it. They were fouled pretty bad, no doubt from flooding trying to start the motor so much. I put a set of hotter CR8E plugs in it gapped to .032 and it fired right up. It runs better than it did before and I can definitely tell there is more low end torque available. I believe factory recommended plugs are either CR8E or CR9E depending upon your climate and other factors. Hopefully these plugs will resist fouling out better. It's not oil fouling either, it hasnt used any detectable amount of oil in 1300 miles. Here's hoping that's all it needed! Now to get on that VRR swap.