Yesterday the wife and I rode about 100 miles or so. She filled her tank just prior to returning home, maybe 2 miles from the gas station. This morning she cranks up the bike and it starts just fine. But the 'check engine' light comes on on the tach and the display momentarily read 'check engine' then alternated between the trip odometer and the check engine symbol. I had her drive down the block and it kept stalling. So in the garage it went. Later today a friend said that it may be 'vapor lock' and to take off the gas cap to let it breath. When we got home about 4 hours later, we did just that and all is okay. So is it 'vapor lock' or improper fueling or what could it be so we can avoid it in the future?