Gas in crankcase

[frozengoose]

I have been doing the "long winter's nap" on bikes out in California for years. Here's what I do:
Putt to the local gas station
Put in 2 oz Stabil
Fill er up
Putt back
Close non leaking fuel shutoff 
Drain carbs
Put on center stand
Put block under engine to keep front tire off the concrete.
Put wrench on negative battery cable and unhook it.
Put my worries on the doorstep..
It's sat as long as a year this way without issue
 

Thanks, that sounds like a good routine. This is the first time I've had this problem and I've ridden bikes since the sixties. My usual practice was to fill'er up on the last ride, then shut the petcocks off when I got back home and let'er idle 'til it dies. Park it on the center stand and put on a battery tender. Never bothered with gas stabilizer and never had a problem with starting in the spring. I lived in the midwest (Ill and Mich) before Alaska, so the bikes were parked for a good long time every year. But, as they say, sometimes shit happens. That's the big disadvantage of running older bikes, parts wear out without warning, often at the most inconvenient time. At least it didn't leak out on the floor and burn the garage down. Right now I've got the old Triumph and an old 4 wheeler in pieces on the garage floor. So will add the 650 to that mess. Eventually they'll all get back together. As long as the T's running, I can direct my feet to the sunny side of the street!

[Darren Williams]

As I scanned the posts, didn't see where anyone mentioned the float seats may be fine, and the culprit in the carbs could be a bad float that filled and sank, thus opening he needles off the seats. If that is the case, it needs to be fixed sooner rather than later, as that has worse effect than a slow leaking needle valve, IMHO.

If someone already mentioned this, my apologies.

[redrider90]

Be grateful you checked the crankcase before firing it up. I had (now I do) no petcock on my riding lawn mower. I went to start it one day and it hesitated then fired off. 10 seconds later the the rod came through the side of the crankcase. The gas tank was empty and I had hydraulic fractured the engine. I had used the mower just a week before. As for gas I top off my 6 gallon Mille tank, add stabile and run it for a few minutes and then shut the petcocks off and run it till it quits on its own.  I use the tank as storage for my generator as ice storms in N.C. have left me without joules more the a couple of times. In the spring I still have good gas and run it off and also use it on the lawn mower. 6 month old gas is not bad even without stabile. Now the country is moving to 15% ethanol.
An easy check on the petcocks is remove the gas hoses and turn them off and see what comes out. Maybe you just had one petcock slightly open?

[Chuck in Indiana]

As I scanned the post, didn't see where anyone mentioned the float seats may be fine, and the culprit in the cards could be a bad float that filled and sank, thus opening he needles off the seats. If that is the case, it needs to be fixed sooner rather than later, as that has worse effect than a slow leaking needle valve, IMHO.

If someone already mentioned this, my apologies.

That happened to me with an antique airplane one day. I knew that airplane burned 6 gallons per hour. Dorcia and I were on a long cross country flight back home, and should have had plenty of fuel to arrive. 
The float had sunk, and it burned 7 1/2 gallons per hour. I saw the fuel gauges getting near empty, but (ahem) knew I had enough as we came over the field. It quit. I looked at Dorcia and said, "not to worry, we still have a half hour of fuel in the other tank." Turned the selector valve, the engine roared to life.. then quit again. Said, "I guess we'll land, now."  Made an abbreviated pattern and a normal "emergency" landing. We pushed the airplane back to the hanger, a tough job..

[frozengoose]

As I scanned the posts, didn't see where anyone mentioned the float seats may be fine, and the culprit in the carbs could be a bad float that filled and sank, thus opening he needles off the seats. If that is the case, it needs to be fixed sooner rather than later, as that has worse effect than a slow leaking needle valve, IMHO.

If someone already mentioned this, my apologies.

Will check everything once I get the carbs apart. Not too familiar with DelOrtos, but have had Amals apart many times, so expect they're not too much different. It's kind of interesting that the 850T, which is ten years older, hasn't had this problem, but maybe that's coming soon? The 650 has twice as many miles, so maybe that's the cause, more than the age. Thanks for all the comments.