Hi all,I cannot figure out where the red/yellow wire coming out of the main switch goes.I connected everything up based on colors, so turn signals, brake lights and high beam works. But low beam doesn't and I think it must be related.  The wiring diagram shows Ry wire from switch going to Ry on left handle switch, but I do not see this because L switch connects to harness under tank via a 4 and 6 pin connector .Sorry for being lazy and asking, its 100F in my garage!

I doubt its to do with low beam.
But more than likely to do with charging when lights are on.
I say that because by memory they're an 'un'--regulated system [this is 1970 remember] [12volt alternator--not brush type generator]. Just rectified & light switch brings in an extra alternator coil to counteract the headlight draw.
I went through this in a way with my ratbike LS2 'rubbish bin bike' which i decided only needed enough charge to keep the battery up for ignition, so experimented pulling alternator wires untill i had 'just' a possitive charge & didn't go up much at revs. Also was thinking less charge so less electrical drag & pony power loss. Worked just great. Ok that's all irrelevant sorry haha.
Then again i'm talking our 'Oceania model' so i might be corrected if yours has electric start & brush generator.

All done by trickery #9 & # 30 rectifier & resistor in the first link. Second link might be usefull too just because.

www.cmsnl.com/yamaha-ls2-1972-usa_model8408/partslist/D-09.html
www.cmsnl.com/yamaha-ls2-1972-usa_model8408/partslist/

This popped up while looking for a wiring diagram.
Be well out of date but could be interesting.
www.aircooledrdclub.com/smf/index.php?topic=28554.0

Yes sir. 
a selenium rectifier, a big resister, and an alternator that has permanent magnet armature, so no brushes or regulator. 
Harness is complete, I think, but no color coded obvious connection.   
Hmmm I am not going to sweat this anymore until I have a crankshaft and know this isn’t going to be a man cave ornament 

Link below to mine if i've linked it right. One at the end of exhaust from the red one. Both pipes were similar
so she went well after that.
I rebored & rebuilt the crank on the blue one.
Found these pics when looking for something unrelated.
I've loaded them on google photos & hopefully linked them.
Was about 10 years ago. Just bikes i shouldn't have sold haha.


photos.app.goo.gl/eNbPUFAVFdk6XipJ8

Michelin PZ2 compound tyres bring back memories .
In the late 70's here in NZ we were allowed PZ2 compounds for Production Racing Classes , but not the PZ4 compound , the Pukka racing bikes were permitted .
Being a bit " Green " back then I had a S 41 PZ2 on the front of my RD 400 . I didn't realise that they could " go off " .
I crashed out of five consecutive meetings before somebody wiser than myself , pointed out the error of my ways .

great pictures RT!
the one with the red and blue front tires touching looks like they are out on a date!
looks like your dog dropped a deuce in that muffler!!!!

Great story Swoop56.
msavitt, yeah i had fun clearing that as was chokka right through & had grown in the port as well.
Didn't want to burn the chrome so found an old fork spring & butchered the end to make a "scratchy thing".
Then i found an adjustable reamer to fit in the end & reverse drilled it by memory--think it had to go reverse to keep the spring tight.
It scratched away all the way through & out the end.
Did it to both sides & poked n scraped down in the muffler & shook it out hoping for the best.
Probably burnt out the baffle though.
Minimal damage welding back together.
Talking burning chrome, [& think i've said it before--but] where i started work we sold Jawas [WHAT i hear ya say] & Czeta scooters & Nzeta scoots that had NZ content, probably wheels can't remember but were a dangerous weapon in theory with the petrol tank out the front.
Anyway, Jawa muffler burning out instruction said despite the chrome going to be blued or worse, your customer will bless you due to the added performance.
Mind you i never had to deal with the likely p$%'d customer What The--did ya do to my muffler.
en.wikipedia.org/wiki/%C4%8Cezeta