4th gen vfr 750. clock draining battery.

After overcoming multiple issues with this bike, upgraded to mosfet, engine replaced due to dead cylinder, numerous bulbs out etc. etc. fireblade shock mod, rear hub freed. CBR600 front brake conversion. I went to take it out today after sitting for a week and Yes! the battery was flat. parasitic drain shows 580ma with clock circuit showing as culprit when clock fuse removed,(drops to 0.002ma). apparently the only thing on this circuit is the clock but it works and keeps time perfect. Disconnected mosfet.. no difference, disconnected other fuses with no effect all showing as ok. clock circuit is defo culprit. Can these dash PCB's be bad or go wonky??

 

My 95 can sit for weeks/months and not seem to affect the battery at all.

My ST1100 clock seems to draw more, but I have zero issues over any kind of reasonable time (multiple weeks into months).

Yes, PCB dashes can, and certainly do, go bad and cause problems. Especially on bikes that have not had a "good" life so far.

 

580ma is way, way too high. Should be in 10-12ma range max. Is it only clock itself? Or is something else sucking up extra?

Troubleshoot circuits that's fed by clock fuse. Disconnect power-input at clock itself and see if drain stops completely, or continues...

 

Clock fuse removed and parasitic draw drops top 0.002ma. R/R disconnected during test too. No other accessories on the bike .

 

The wiring diagram certainly only shows the clock on fuse F feeding a red/green wire. That wire runs through a green 10P block which also connects to other things in the instruments, so it could be useful to disconnect that block and see if the drain also stops. If it doesn't then your drain may be somewhere along the length of the red/green wire.

 

Problem is downstream of fuse, not right at fuse itself. Might be scratch in that power-line to clock that's shorting against frame or other wires. Need to narrow down where along wiring between fuse and clock drain is occurirng.

1. disconnect power-input as close to clock circuit as possible.
2. measure drain with only clock itself disconnected, what's drain now?
3. IF drain drops to 2ma when power disconnected at clock itself, then short is inside clock. Only repair possible is new known-good clock module.