02 Bird 37,900 miles. Serges at a constant throttle setting. Idles fine. Seems to run fine when throttle is applied. Have replaced spark plugs, air filter and run a can of Sea Foam thur. Nothing helped. In neutral applying the throttle to increase revs, bike does not sound smooth. Bike does not back fire. Old plugs with 37,900 miles on them didn't look too bad. This problem seems to have delevoped overnight. What next Doc?
Thanks for any help,
John