Motorcycle Repair: Hyosung 250, vacuum leak, sport bikes

Question
Hi,
I Have a 2004 Hyosung Alphasport 250  and it keeps cutting off while of driving down the road... The bike will start to jerk a little like its pulling and then when I stop or pull the clutch it will cut off. Could you please advise me in what might be wrong? And is it true that sport bikes only run on premium gas?

Answer
Mike, I don't have any references for your bike, as far as parts goes. If it has a vacuum operated petcock, it could have a bad diaphragm, which makes a vacuum leak and shuts down fuel flow at the same time. I don't know if your bike has that setup or not, but they are not that uncommon.

Engines stop due to:
Piston seizure from lack of oil
Lack of fuel being delivered to the carburetors
Intermittent spark due to CDI ignition issues

Your owner's manual should list the type of fuel required for your machine, but I doubt that it needs anything more than 87 octane in a bike like that.

http://www.hyosungmotorsusa.com/company_info/contactus.asp for parts, service and technical questions.

Bill Silver