I have a 06 ds650 with 11.1 piston,K&N and tip, when starting the bike if it don't start on the frist couple of revolutions it back fire thru the carb and eating up the sprage clutch, i've tried modified carbs but no change, the mods have be on the bike for about a year, most of the time its start on the frist revlution but if it don't there goes more money. Has anyone had these issues and is there a fix?

 

There have been reports that some of the aftermarket igitions can cause this and yes it is hard on the sprage.

 

How old is your battery.
May need new battery or keep battery charged up.
Clean ground to frame.
Run a ground wire from motor to ground on frame.

OMR

 

I'll try the battery, it still has the stock igition.