Triumphrat

I have a 1993 trophy 1200 with21250miles on the clock the battery goes flat after about 5 days use of commuting to work ,I have fitted anew battery but still the same .put a volt meter across the battery it shows 12.75v at tickover is this normal?

stevent

No, should be 13.5 ~14. My guess would be either your alternator or voltage regulator is bad.

__________________
stevent....."May the Goddess turn the hearts of those who hate us, if not their hearts then turn their ankles so we'll know them by their limping..."

Timtiger

You may also have something simple like a bad earth.

To check the alternator output (rather than the voltage across the battery terminal, trace the wires from the alternator and test here. You can put the voltmeter probes into the 2 pin connector. See what the voltage is at idle and also at 2-3,000RPM. Test this with the 2 pin plug connected. DO NOT disconnect this 2 pin connector. If you do this when the motor is running, you may fry the $800 stator!

If the voltages are different, you may have a wiring, earth, fuse problem.
Hate to deliver bad news, but there have been a few reports of bad alternators in this forum. I have had one myself on my 955 Tiger.

Good luck.