need advice on sputtering engine
1997 Vulcan 1500 classic. Checked the air filter and crossover for blockages and proper sealing, also checked the spark plugs for corrosion/wetness. the plugs had slight dusting/buildup on them and so I brushed them off and put them back in.
The bike starts fine and idles normally. If I give it throttle while idling, it's fine, makes no strange noises.
Most of the time when I ride its fine, no problems and I can go 100mph for miles with no problem BUT sometimes it starts to sputter/stall around 70mph. If I give it throttle at that point, there is no power and the bike starts to slow down.
After slowing, I can resume riding normally until 65-70mph where it will happen again. When I let go of the throttle, it backfires quite a bit (more than normal).
WHAT IS HAPPENING??!