Motorcycle Repair: My bike wont start., gas stabilizer, yamaha yzf r6

Question
I have a 1999 Yamaha YZF-R6. After putting 90 miles on one day (it ran great for those 90 miles), I stopped by my moms house and when i got ready to leave, the bike wouldnt start. The next day i replaced the battery (it was weak, but was not the main problem), I also removed the fuel pump relay and cleaned it, and also cleaned the fuel pump itself. While i had the fuel pump and relay out, I tested that they worked properly, and they work as they should. My question is this, after cleaning and repairing the aforementioned parts, what else could lead to this problem? When you hit the starter switch, it turns over but does not start. If you give it full throttle when you are pushing the starter, it will eventually start (after slowly sputtering like it wants to start for a minute or so). Could it be the ignition module? Should i try to clean the carbs out? Another strange thing is when the bike is cold, it will start usually right away (after giving it full throttle like i mentioned before), but after riding it and warming it up to operating temperature, if you stop it and try to start it again it wont start at all. The bike just turned 5000 miles and i live in Wisconsin, doing mostly city and freeway riding (unless im lucky enough to have more than an hour and can get out in the country). Thank you very much for any help you can give me. I really appreciate it.

Answer
Hi Karl,

Very good description/narrative, thanks.

If the MC was stored over the winter, gasoline in the carbs may have varnished. This is very common and gives symptoms as described. This is the number one service repair at dealerships every spring.

Yes. A defective ignition may cause similar problems.

Too much gas stabilizer seems to cause similar problems, as well.

I would remove carburetors and investigate for varnishing. Thoroughly clean and synchronize carbs.

Remove, inspect, clean, and re-install spark plugs.

Send me your emaill addy as requested. I'll return carb cleanin, tuning, and synchronizing info files. Keep me advised of your progress. Send to: mshively1@woh.rr.com

p.s. I've been to Blackhawk Farms Raceway a few times.

Respectfully,
Mark Shively
Dayton, Ohio