1200 Sporty engine problem

My 2000 Sportster 1200 seems to be missing bad. I replaced to manifold seals but it still seems to miss really bad. Occasionally it will work itself out, but then goes right back to acting up. The other symptom is that the speedo will cut in and out as the motor misses. What would cause this?

just a quick one here but check the plugs and wires, coil, and another thought are the 2 in common?, just some thoughts, hope you find it soon

Sporty1986 - Is the bike backfiring or does it act like a dead cyl.?
Ironhorse hit on the electrical problem but need a little more input to help.

Unless you have one seriously bad intake leak it won't affect higher RPM much and generally won't cause this situation...
I would start by doing the basic trouble shooting steps.
Start at the problem and go backwards using your service manual (you have one right?) it is the most important tool you must have to work on your ride.

Bad ground
Bad ignition box
Bad coil
Cracked, broken intermittent short in the ignition circuit.
IIRC the 2k still had the tach trigger sensed off of the firing pulse for the coil. So, if the tach takes a dive it is electrical.

Bad circuit breaker (15 or 30 amp) can cause issues if they are failing. Do the lights flicker when it is acting up?

Sure sounds electical,with the speedo cutting out..you got a wireing diaghram.I would check all connections...starting at the battery..ground might have a bad connection Like CD said...Good Luck

Missing

Can you duplicate the problem by wiggling KEY or wires ???

My sport had a bad ignition key switch and acted very simular to your problem.... Just like turning off key and back on.........

does it also BACKFIRE when you are at cruise speeds while it misses??
How often does it do this ....on occaision are all the time???? Idle only or under way cruising??

The crank sensor might also be bad....