Charging Issue On A 2001 Legend Tt

https://www.triumphrat.net/speed-tr...-diagnostics-rectifier-regulator-upgrade.html

 

The alternator voltage is typically below the battery voltage at low rpms on these bikes and won't charge the battery until someplace around 2500 rpm. That's why Triumph specs the alternator at 14.5V at 5500 rpm.

Your battery voltage should be 13.2V with the ignition off and you'll have a slightly lower voltage at an idle.

Roll up the idle slowly while monitoring the battery voltage and it should increase to 13.5 or more by 3000 rpm.

ALSO, wire brush your battery terminals and cable ends until shiny, coat with hi-temp wheel bearing grease and reassemble!

A dirty/oxidized terminal will cause a resistive voltage drop that increases with current, so the harder the alternator tries to charge (higher voltage) the more the voltage will drop before reaching the battery.

A defective battery with excessive internal resistance will cause the same problem as dirty terminals -- but you can't fix it.

 

The R/R is built into the back of the alternator on your TT and there are a few connectors between the alternator and the battery that could do with checking and cleaning, you will need to follow the wiring from the alternator to the first connector ( a double ) where the alternator wiring connects to the main loom

Your R/R is here
http://www.worldoftriumph.com/trium...r?block_01=&block_02=302234-3-2&block_03=9412 Item 16

 

Had another look, your TT feeds from the alternator via the fuseblock, I would check all the fuses and connections are clean and in good condition, replace the fuses if in doubt.

As well as the earth connection from alternator case to chassis or battery negative whichever it is.