Turned on ignition on yuasa batt pressed horn got a donk. Been on optimiser for a year. Multimeter connected 6.1 to 4.8 when horn button pressed. Indicators as well wont flash. Awaiting motobatt delivery and will report back. Do I need to charge the glass mat battery? 

No simon "  it should be plug and play,   i cant get a moto-batt for the twinshock models,  as the battery is housed in the oil tank, [ below seat]

i have one,[ 6volt]   moto bat,   i use it for testing electrics on DT,  as it hold up long time,,,,[  thats  not" me  luv you long time " ] 

Ta bh. Me so....   I like the film too

Horny donk

 

The donk has gone and bike is Horny again. Indicators JUST ABOUT flash with ignition on and bike not running. Volts drop to 6.1 during load. Batt was fully charged when delivered. 6.49 volts. Acid depleted below min in cells 2 and 3 on old batt. 

That sounds normal,  it will get better with use,  would you believe , i have an MF  6volt    on my Dt400 ,  [there tiny too ]  its lasted 2.5 years, and its been flat [ non charging]  a few times,  it just keeps coming back ,

My first glassmat. I know there is a voltage drop somewhere poss ig switch earth etc. Loom is brand new. As the oil light dims on flash.  

most likely dirty contacts in the ignition switch Simon, if you jumper a feed to the flasher relay brown (at a guess) it will prove that

Will do. Ignition is original with yamaha key so quite possible