Hello, Recently obtained a DT100. Very original looking bike, last registered in 1983. Trying to breath some life into this gem after 37 years of neglect.

No paperwork, lower section of the frame tag is worn, can't figure out exact year/model.
its either a 78 or 79, and letter designation unknown ( dt100 a,b,c,d, etc. )

Kick starter busted, and basically every electrical item was suspect upon further inspection.
-Battery toast ( obviously lol )
- headlight/tail lamp burnt
- diode rectifier melted
- rear tail harness shredded by tire
-no spark, no voltage from ignition source coil
-gauge lights burnt
-ignition coil primary winding shorted
-points and condenser bad, someone stripped one of the main stator assembly screws.

So far i have replaced
-tires and tubes
-headlamp/tail bulbs
-gauge bulbs
-points/condensor
-ignition coil
-diode rectifier

Now gets power at coil + and battery + when kicking, but no headlamp or neutral light
Tail lamp and gauges will light up with key on.

Bike will still not start.... no spark. possible bad new coil. thinking of going CDI ignition, not sure.
looking for a proper wiring diagram, the 76 dt100 diagrams do not match this bike. seems like a transitional year bike.

Also whats the deal with dt100 a b c d etc.?
Thanks

Looks like a nice project... the points are a great system in my experience so I wouldn't give up on them.

Check the VIN in the Tech Library here to confirm the year... might have a manual there too.

In the USA, 1974 was the first year Yamaha called everything a "DT". So 1974 was "a", 75 was "b", 76 was "c" and so on... yours is probably a 1978 (e) or 1979 (f).

^^

Thanks for the heads up. Looking for manuals to purchase, was not sure why the letter designation.
vin is 2f5-3104, ill check the site cross reference

That is a 1978 DT100. it shares the same colors that a Sunshine Red 1978 DT175 has.

Now armed with an accurate wiring diagram I dove into the harness and located a few shorted wires, and flasher relay shorted too.
Hard to spot but all the small kinks are fried sections of loom

Yes mystery solved. Didn’t realize red color was a one year option until directed to the site tech articles. I Attached the findings above for future reference.