Overall Performance restoration - 1980 gsx750

[alke46]

On a side note, I just re-read this thread and just out of curiosity, not related to your issues, but have you checked the valve clearances?

Good to know the cap replacement helped.

[CincinnatiKid]

Yep, earlier this summer I checked them and maybe one or two out of 16 needed slight adjustment. Overall it was pretty on.

[CincinnatiKid]

iridium plugs came in yesterday (for the winter time), and of course they are resistor plugs.
so 5k resistor plugs plus 5k plug caps = 10k resistance in the circuit. right about where i started.
engine seems to still run fine, didn't revert back to it's old bullsh1t, so i'm interested if dropping back down to 5k ohm is going to make a noticeable difference.

going to pull out the resistors in the caps, but of course, 2 of the shorter plug caps can't be opened up, so i had to order 2 more of the long ones....

new tires just went on yesterday. found some Avon Roadriders in the stock sizes 19-3.25 and 18-4.00, handles better than the 120/90-18

[posplayr]

Installed new spark plug boots. all are 5 kOhm. the old ones tested 9.3, 9.6, 9.7 and 11.2 kOhm. that 11 seems off. any idea what the plug cap should be?

Did some voltage testing to confirm proper electrical continuity and health:
Battery @ Rest (keyswitch on, lights off) - 13.63v
Battery @ Idle (lights off) - 13.5
Motor running @ 5k - 14.7v

Measured voltage drop between the battery positive and the coil side of each coil's plug to the wiring harness
Coil voltage drop @ idle - .11v
Coil voltage drop @ 5k - .04v
Both coils gave the same reading, as expected.

So unless something occurs under load that isn't happening in the shop, the ignition seems to be in good health.

Those measurements do not follow the Quick Test so they can not be used conclusively to assess the charging system. The bike is charging, but how well is still subject to some level of doubt.