Hi guys, quick question... My LS650 bobber (RYCA) runs like a dream, or so it seems. After about an hour of riding the bike starts spluttering and it almost seems as if it's losing spark (or fuel) or god knows what. It takes a lot of coaxing to get her home, to the frustration of all my mates. Once cooled down she runs like a dream again. What could be the cause? Coil perhaps? Has anybody experienced the same? Cheers

The stock petcock can cause some wicked confusing symptoms.  Try it on Prime when it acts up and
Pop the gas cap open and close it, then see if it runs right or better,
A full tank with a clogged vent will fail to deliver fuel right sooner than a half tank.
If it's the same behavior at about the same time, I'd be questioning the coil.

But not before I looked at the things here.
Don't let it idle on the sidestand.
Clear the crud from around the spark plug before you pull it.
A Raptor petcock is almost everyone's answer to that turd that comes stock.

Year and miles?