Need some help. I have a 70 Bonny. Stock motor new,stock carbs, new also. everything on the bike is new. Boyer Mk111 ignition with 6 volt coils. My problem is this. When I have a fully charged battery,14 volts, this thing runs fantastic. However after running for about150 miles she starts to falter and just keeps getting worse until I charge the battery again. EVERYTHING, and I mean everything checks out as OK. Went through the wiring,the charging everything. The only thing that I can come up withis the possibility that the battery is too small. I have an 11 amp battery in it. If I leave the bike sit for about a week the battery voltage drops to around 11.5 volts and the bike runs like crap. Any suggestions from you guys would be very helpful.I have checked out the wiring numerous times by myself and by an old Triumph mech. Everything fine.