Hi, Donald and the usual suspects are:
1. Fouled spark plugs.
2. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a preliminary reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
3. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
4. Loose connection at ignition coil or plug between ignition sensor and module.
5. Spark plug cables in bad condition, shorting/leaking, spark plug cable connections loose check for spark leakage in the dark.
6. Faulty ignition coil or electronic control module.
7. Faulty pulse coil.
8. Faulty CKP, CMP, or BAS sensor.
9. Faulty ignition switch.
10. Faulty run/off switch
11. Tilt sensor needs a reset.
12. Security alarm failing to disarm needs reset
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Most Honda bikes of the 1980's had small fuse boxes with 3-4 fuses at the most. Usually 1 for ignition and charging, 1 for Headlight Only, and 1 for All other lights. Overheated and even melted fuse blocks are commonplace in these years due to high current draw and the plastic block which melts and distorts over time, breaking the circuit to the lights. Replace all 3 or 4 circuits of the old fuse block with modern in-line blade-type fuses and this will never happen again. (If the fuses are all good, and the plastic box is not melted or burnt, you may have a bad Ignition Switch, but this is rare)
Sounds like no timing advance. Will seem to go well up to about 55 or 60, but will run flat or even slow down above 60. Follow shop manual procedures for verifying timing advance operation. If you watch the timing mark with a conventional timing light, you will most likely discover the mark will not move when you rev the throttle. If this is the case, you must replace the electronic timing pickup or module. Consult shop manual for the correct procedure.
Corrosion in the electrical contacts and the ground wires and bolts. You will need to take them apart and clean them - use fine emeri paper. Also check the battery plots and cable connectors for oxidation.
Hate to sound like a smart $$s but if you have got to ask then you don't have the tools or mechanical knowledge to do the work. If you feel the rods need replacing I'd strongly suggest ether finding a motorcycle mechanic or purchase another bike. This is not a simple repair and it's costly certainly it will cost more to repair then what you could get another bike for