(1988 bmw k100) not 100% sure what happened bike was starting and running fine and then i tried to wire up an aftermarket tail light and now suddenly i have no lights when i turn the key and it won’t even attempt to start, i charged the battery and it’s still doing it. any tips?

put the old light back on ?

You've most likely cross-wired the new tail light and shorted one or more fuses. If the new tail light is LED then it's possible you've fried that as well.

Dai wrote:You've most likely cross-wired the new tail light and shorted one or more fuses. If the new tail light is LED then it's possible you've fried that as well.

i didn’t know cross wiring was an issue, i was testing the different wires by taping them together and trying to use the blinker. it definitely sounds like this is my issue thank you!

Don't let the smoke escape.

Two Wheels Better wrote:Don't let the smoke escape.

what? lol

When asked how a man is meant to drive home with often-failed Lucas electrics, rendering headlamps useless, it was reported that Lucas' reply was,

"A gentleman does not motor about after dark."*
-Joseph Lucas, aka The Prince of Darkness

*I did not verify with Snopes.

rubbish

firstle wrote:rubbish

Yes, Lucas stuff surely is.

there from the beginning when few knew how to maintain dynamos etc let alone carbide , you are ill informed or just plain stupid 

It is honourable you feel the need to defend the company but there is no reason for name calling. 
It is not personal affront. Please restrain yourself.

ok , what personal experience have you with a lucas product i maybe able to help , or are you just spreading something you have been told etc . heres another one for you , elvis is alive and living on the moon

Despite all of the grief that Lucas gets, I owned a high mile beater MG while in college and the Lucas electrics were the one thing that never failed.

The real problem with Lucas electrics on motorcycles was the lack of a dedicated earth wire. There you have a miserable six volts trying to fight its way back through thick greasy headstock bearings with no guarantee of a good earth connection... add poor maintenance and headlight reflectors that have lost most of their reflectivity through age and no wonder that the available lighting was so poor most of the time. 

It's also the reason why I always add a dedicated earth loop to any wiring harnesses I make, whether there was one originally or not.

I never owned a vehicle with Lucas parts, but my son owned an early 70's Spitfire, a brother-in-law owned a couple MGBs and MGAs, and I had a female acquaintance who owned a 1968 MGB in the late 60's.   I watched all of them struggle with starters, generators, ignition coils and voltage regulators, especially voltage regulators that seemed to delight in frying batteries. 

I know my son didn't have a reliable vehicle until he replaced the wiring harness with one he built himself and several of the Lucas components with aftermarket.  Until that point, there were several occasions when I had to tow his non-running car home. 

In fairness, maybe the cars built for the North American market were built with parts manufactured to a lower standard.

no difference in the item just a simple lack of understanding for how things work , its very very common 

delete duplicates

That's almost not fair. Add to my list people who used to abuse the adjusting screws to try to get more voltage out of the regulator than it could safely deliver. Result = burnt-out regulator coils. Lucas' automatic regulator was a distinct improvement over the manual one.

Post WW2 Lucas suffered from the usual problems as did many UK manufacturers in that they had old production lines that were either worn out from heavy use making military stuff or rusty old junk that sat for 6-8 years where as Bosch had new factories because the old ones did not exist any more. The bike manufacturers had similar problems and didn't recover.
I have had several bikes and cars with Lucas electricals and they weren't the best but for the time were mostly OK.

more volts for the 6v or 12v systems , adjusting the cut out incorrectly will result in damage (over charge)  , which year are we talking and on what ? have you a regulator model in mind which has been altered to this extent . i still run 6 and 12 volt systems dynamo , 6volt lights are a lot better now with the led bulbs but i still run filament as i think it suits the bikes better more in keeping . lucas mag/dyno

Sorry Craig - I'm not sure if you're talking to me or Rick?