So I've neglected to ride my bike except about 2 times a year the past two years. I pulled it out today to fix it up and charge it. Then fired it up to let it run a little while to get the gas through the lines. It's a 2008 GT250R. I put about 11500 miles on it from 2009-2013. Prior to today it's never had an issue after running a while.
So long story short, after it sitting and idolling for a while (15-20 min) with light revs, after 10 mins, I decided to hop on it and go for a ride. I dropped to first, gave throttle and I heard a thud thud thud from about 0-1500 rpm, then it sounds normal. But it wants to stall out in the mentioned range. Fearing the worst, I didn't go anywhere and parked it. If I had gone out for a ride, I didn't know if I could stop and have it keep running. It stalls out if I'm sitting still holding the clutch in 1st. What does everyone think? Valve issue? Cylinder? Being paranoid? I've never heard this before or had it stall out like it is.