Hey all, new to the Yamaha enduro world. I recently picked up a dt250 engine, vin dt1-06692 (should be a 61”?)

I will be using the engine for a small project so it will not be going back into a dt250 frame. I’m just trying to figure out how to get the ignition wired up to run mx250 style, no lights, no battery. I bought an ignition coil that said it would work on a dt250, although it is Chinese made.

how would a guy go about wiring up this engine to run? I have four wires coming out of the left side of the engine, one white, one yellow, one green and one black. Using a test light I have power coming out of the black and the yellow wires when the engine is turned over. When I look at a wiring diagram for a 61 dt250 I see the black wire should be hooked to the coil. When I connect the black wire to the coil… nothing happens. I took the flywheel off, cleaned and adjusted the points, and still nothing. I have experience with small engines but not with points ignition, so any information is helpful.

Welcome from NZ. I guess you mean 1968 DT1but all the mags are the same on points ignition. Just black to the coil. Coil earths to the frame. Could check the points are contacting with an ohm meter on the lowest setting. The variation on an annologue style meter is very little so look close & just move the flywheel forward & back over the opening moment & move it slowly not fast. Not much needle movement but you'll see it. I have a points meter from old which give a big movement but anyway--my DT1 seems to just keep going & not touched the points for a lifetime. It's possible but unlikely the source coil is toast. If ya get desperate ask me how i used a lighting coil wire once to get something running but not a long term solution. If you have a drill with enough grunt you could remove the plug--or both plugs if has two, then spin it up anti clockwise & see if a visible small spark at the points in the dark. Set the plug gap about 20 thou, dont go car plug gap which i've seen up to 44 thou on NGK11=11x4=44thou i think haha. Best of luck. ps one more thing, on the old DT1 there's a short black coming off the long black. Don't earth that as its only for--whatever ya like--kill swith--points checking ohm meter etc, just don't earth it. I know Chinese coils get a bad wrap but i've not had any problems-so far. If it reads something small on the primary & something big on the secondary it should be good.

Greetings from Tennessee 

Yes 68”, have no idea why I put 61”.

Anyways I have the black hooked to the coil. Currently I have the ignition coil vise-gripped the the engine cause it’s on the table at the moment. With the coil grounded to the engine I turn the engine over, by hand or with a drill I don’t get power at the black wire anymore, as soon as I take the coil off the block I get power at the black wire again. No sparks at the points either way…

Now i've written an essay ill add up a bit more up here. I think i'd look for other causes before trying my experiment below.

Ok, i probably shouldn't tell you my stupid ideas but if you think the source coil is faulty, iused one of the lighting coil wires but was on a little 100 with only one lighting coil. I experimented & ended up with te lowest output. Yellow is your highest so use one of the others but you should get an instant visible result from the yellow with wild spark at the points. With mine i snipped the ignition source where it joined to the condenser then simply fed a random lighting over to the black up top where the mag loom ends--where your black ends that you're running to the plug coil. That just fed back down to the points & condenser & you're still joining it--black with a lighting--both into the plug coil wire. I'm not sure how it would play out if you simply snipped nothing & poked a lighting into th black up top. Doubt you'd cause any damage at turn iover speed just to try. Was many years ago i did this--in desperation to prove a point--faulty ign source it was!!. Also on those the ign source earth into one lighting coil. Mine has no lighting coils so just earthed the source seperate with terminal to a coil screw or stator plate. Think i'd try a few things first though--nothing shorting the points. Has someone fitted points wires under the insulating washers instead of on top. Honda single wire mag coils have the condenser as part of the plug coil which is all good too.

Gotta use the right puller for the flywheel too, which is 27x1 left hand thread.
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Flywheel must be tightened good & tight as shear of crank keys otherwise.
When using puller remove any washers--spring & thick flat if there so puller gets a full hold as is a fine thread & easily compromised.
Back the puller bolt well out so you dont get a false impression of when it fully home in the thread.
I shouldn't ask i know sorry & just cvering bases but you have it spinning anti clock by drill. Probably spark both ways anyway.
I've seen an almost invisible sliver of something steel the magnets got hold of & deposited it across the points terminal bolt shorting it to earth--well saw that about 50 years ago at work--can't remener yesterday though haha.

Yes turning counter clockwise. I’m starting to get a little bit confused… I have my multimeter hooked up, could the points seem to be shorted to ground? When I put one lead on the blue wire going from the points to the condensor, and the other lead to ground I’m getting a dead short with the points open or closed

If you saw voltage at all on black, points can't be shorted.

You need to use a meter with Rx1 ohms scale.  Very small change in resistance when points open.  

Reading should be perfect 0 ohms with points closed and about 1 to 2 ohms with points open.

Cleaning the point contacts is always a good idea.  

Lots of problems with brand new generic Chinese coils...  (only RT325 seems to have had good luck with them. LOL)

Emgo makes a coil for about $15 that myself and others have had good luck with.

Am I correct in assuming that if it was a bad coil I would still have a spark at the points?