Carburetor bowl gasket wore through due to use of ethanol fuel drying out the gasket. Note: Manual does state that 10% ethanol is the MAX you can run. You are now taking into account that the pumps are being honest when they say contains at least 10%. That at least means that it could be higher than 10%. Solution: run Stabil Marine formula (dark blue stuff, not the red) or sea foam ethanol treatment. Those products at each fill up, as well as running the fuel out of the carbs when you are done riding, has prevented this from happening again. This leak started around the "teens" thousands of miles. No issues since, and over 21000 now. Only other complaint is the seat takes some time to break in.
Pipes did blue, but you must figure, I bought it in California, moved to east coast, sitting in traffic jams. The bluing was not fuel related, and was the result of no air cooling the pipes when you are sitting in a backup on I-95 waiting for someone to move (and you can't lane split over here...boo) And it has over 21000 miles on it in less than 3 years.
Great ride. Maintenance schedule employed: 600 mile check up, 4000 and 6000 mile service. Nothing later until 14-16000 miles when I had major tune up done (includes valve clearance check/adjustment - recommended at maintenance interval in manual) Everything else has only been oil changes. Change the oil filter out at every 6K miles, with an oil swap (drain and fill, no filter change) every 1500 miles.
Aftermarket parts are not too hard to come by if you know where to look and do not buy the first thing found. Cobra pipes were less than 500, carb jets were less than a hundred, and a K&N high flow air filter for about 50. If I keep it under 70 mph, I can squeeze almost 54 mpg.
I would not worry too much about oil types, yamalube 4 is what manual states, but Rotella T 15W40 or motorcycle specific oil will do fine.
If you need the bike to move, roll the throttle. It'll get you going, promise. Even before the upgrades, it would hold its own on the freeways. If speed is your thing, the electric ignition tops out at roughly 115 mph. Highway cruising, 65, 70, or 80, it can do it. I have made runs from VA Beach to Baltimore doing 85 all the way and no problems. The bike has plenty of power to handle a 6th gear, but there is only 5. Either way, you almost don't need it, although it would be nice to have. The bike will seem to get angry at you in between 70-75, but smooths out nicely after 75.
Handling wise, I have dragged the floorboards more times than I can count, because it does not feel as if if you are struggling to pitch the bike. High speed maneuvering can be a bit tricky; she gets locked in a line and does not want to swerve quickly, but a firm handed approach will slide the bike easily. Slow speed, I passed the MSF experienced rider's course dreaded figure 8 box on first try.
This bike has never disappointed me, nor left me stranded. It was made to ride. So ride it. I would recommend pipes after purchase, it kinda sounds like an angry sewing machine with stock pipes on it.
Honestly, for 9 thousand bucks and pretty much nothing but oil changes, this sled doesn't owe me a red penny. Great bike.