Long story short. I bought an 81 750 a month ago. 18k miles, 100% stock. Bike ran fair, but wouldn't rev past 5500 and idled a little erratic. New plugs, valve check (.004 to .006, all within spec), adjusted timing chains, rebuilt carbs, bench sync.
Bike ran noticeably better, but popped out left exhaust at idle and surging at cruising rpms. Synced carbs on bike, symptoms got worse.
Pulled the plugs. Number one is very very lean, number 2 is very fat, and 3 and 4 look acceptable.
Did a compression test and found this:
Cyl 1: 75
Cyl 2: 25
Cyl 3: 50
Cyl 4: 50
Brand new compression tester. How could it even run with numbers that low?
Bike ran noticeably better, but popped out left exhaust at idle and surging at cruising rpms. Synced carbs on bike, symptoms got worse.
Pulled the plugs. Number one is very very lean, number 2 is very fat, and 3 and 4 look acceptable.
Did a compression test and found this:
Cyl 1: 75
Cyl 2: 25
Cyl 3: 50
Cyl 4: 50
Brand new compression tester. How could it even run with numbers that low?
Last edited: