Bike died

martin_csr wrote:

I would swap in new fuses as a just in case. Assuming you have the stock-type glass fuses, sometimes a fuse can appear good but the fuse wire between the end caps can be separated from one of the caps. I've never seen this, but apparently it's a thing.

ps: be sure to use the correct size fuses. i.e., correct amps. the stock fuse box may have a label or it could be embossed with the info.
 

Definitely a thing.  The fuseable link in the OEM 20A glass fuses of Z1's was attached to the fuse end caps using solder.  Those fuses run hot and, repeated thermal cycling would crack the solder joint(s), leading to intermittent or sudden loss of power.  We've replaced the 20A glass fuses in all our Z1's with modern blade fuses using fuse holders and crimped bullet connectors that look clean installed, tuck into the same space as the OEM fuse holder, are far more electrically sound and, easily reversible, as the bullet connectors make no harness butchering is necessary.

Good Ridin'
slmjim & Z1BEBE

Thanks guys , got it home yesterday and found battery totally dead, strange as it was fine earlier so did flicking lights on kill it perhaps?
fuses all good .

A battery can fail internally quite suddenly, producing full no-load voltage (DMM) but near-zero current when loaded.  We've seen it multiple times.

Many years ago, early eighties ~ mid nineties (before the interwebs, AGM and LiIon batteries) an article appeared in Sportbike Magazine re: SBFS (Sudden Battery Failure Syndrome).  We've looked for the article a few times since then since & haven't been able to find it.  The article addressed the situation in which an apparently healthy wet cell battery will be fine one moment, then inoperative the next. We've seen it ourselves a few times, specifically with YB14LA-2 and YB14A-2 batteries (Z1's and '91 - '03 CB750 Nighthawk's respectively), always with batteries only 1 ~ 2 yrs. old.. Testing with a DMM will show battery voltage but, load testing reveals a battery that makes plenty of no-load voltage but cannot produce any significant amount of current under load.  The problem identified in the magazine article was a buss connector between cells that would crack open.  It was identified in the article as existing in U.S.-produced Yuasa batteries sold under a variety of brand names (Interstate, Diehard and others).  Our experience was, battery would be fine, then turn on lights or attempt to crank, there'd be a 'SNAP' from under the seat, then dead bike.  Full batt voltage on a DMM, no current / fractional voltage under load.  Weird...

Since then, we've studiously avoided any bike battery  made in the U.S.  We've never had any problems with Japanese, Taiwanese or Vietmanese wet cell batteries, all of which die a predictable, gradual death at 4 ~5 yrs. of age.

What we think we've learned is, the only battery test one can count on is a load test.

Good Ridin'
slmjim & Z1BEBE

Completely agree Jim, testing a battery "off load" is like "free running" a starter motor off the engine - doesn't really tell you anything about it's serviceability   and if anything sends you down a rabbit hole looking for problems elsewhere