I need to know the ignition source coil resistance spec and the part number for the source coil. I looked all over this site and could not find this info, any idea where to find this?

from Salisbury, UK.

These should be in documents in the Tech Library (see top toolbar) - to get you started there are a couple of links below!

yamaha-enduros.com/index.php/parts-lists...-rt-2-3-parts-manual

yamaha-enduros.com/index.php/workshop/se...360cc-service-manual

The ignition source coil 'in the mag' for DT3 says 0.508 ohms. That's the black wire but you'd have to de-activate points & condenser. But the blardy stupid thing is DT2 says 1.53 ohms. RT3 goes 0.508. RT2 goes 1.53. Confused--i am. Take ya pic. points source coils never play up --Nearly Never--unless damaged by someone sticking a flywheel holding tool too deep in there. 3 of my bikes shouldn't even run looking in the mag but so far they've never faltered. Tell us ya story please. My readings are straight from the yamaha bible we used in the yamaha workshop where i worked back then.

I got the parts list and shop manual ok, but nowhere does it show the color of the source coil exiting from the mag. I have not opened mine yet but plan to jump a line from the source coil directly alone to the main coil to see if I can get it to spark. It lost spark shortly after i had removed the gas tank and wonder if somehow I have shorted the source coil wire on its path to the main coil.
My 1973 DT3 enduro has few miles on it. I am 83 years old and used it only to go around the farm occasionally. This forum seems to be the best source of info I have! Anyone know the wire color?

Black wire.

Common thing is there is a short black "jumper wire" in the harness coming out of the stator on many models. It has a nice female bullet connector that looks like it should connect to something... and black so it must be ground, right?

Wrong, it just hangs there. Used to make it easier to connect a meter to points wire when setting timing. Grounding that wire will kill spark dead.

Just grab the black at the top of the mag loom & go straight to the plug coil. Be sure the throttle is fully closing as no easy way stopping it. 83, wow i'm 74 & now feel i'm just a boy haha. Welcome if ya new. What part of the world?.

Oh, & what MarkT said above, incase the short black branching off the main mag black 'if it's there' has been earthed. I know black sounds like earth but not in the case of the mag. On the other hand Black of the Main Loom is earth & main loom will be earthed to the plug coil mounting bracket. Yamaha's eh!!--who'd hav em.

I am in Union, Mo. just outside StLouis. The bike is at my neighbors place and I have not seen the mag wire bundle, I hope I can find the black source coil wire and run from it to the main coil to get spark. If not, I guess the source coil is dead or the points, condenser, main switch, are at fault somewhere. He put a new main coil on the bike already and no spark then. I made up a tool to replace the plug and show a spark if there is one.
I cannot read the wiring diagram on the owners manual, not knowing if the dark lines are hot or ground and if they connect when crossing or not. Also, what are F and H at the top left of the diagram? Also what are the Ground and Common circuits mentioned in the color chart? They sure make it hard to locate the mag output wires and their colors. You guys here are the best info I have found!

My head hurts following diagrams. The mag loom end will be easy to find then just black from that to the plug coil. Only one wire into the plug coil. Don't loose the old plug coil, they rarely fail & often get blamed when its something else. if ya neighbor's been in the mag then i'd have another look. If not then give the points a scratch if you can get at them & also check they have some gap 15 thou max but anything should see it run. If you have an analogue ohms meter set on the lowest & onto the mag black then as the points contact or part you'll see a very slight but definite variation in the needle. Needle will move a little & hold until you move the flywheel back & same deal--move & hold. Just proves they're contacting that's all. Otherwise pull the flywheel for a look see. Flywheel puller is about the most common one around & cheap as chips. 27mm left hand thread 27x1 pitch fine thread. If you go that way then remove any washers behind the nut so the puller will screw right home. Back the center bolt way out so it doesn't strike the crank & you then think the pullers fully home as they can easily pull that fine thread out of the flywheel. Anyway--nuf said for now. I'm In NZ by the way. Assembled & worked on those from new plus raced one 'DT2'. But of course the mag never gave any trouble back then. Have a happy day--i hope.
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