Hey William! I'm a Mr. Bill too.

On the spark I'm not sure how you're finding power with a test light at the plug. They have a magneto ignition and there shouldn't be any electricity present until the motor spins. In fact the ignition is a stand alone circuit. A battery isn't even needed.

You do need to make sure it's not grounded somehow because grounding the mag is how they shut off. Either thru the key or a kill switch.

Under the tank there's a black wire out of the stator harness you can check. If you unplug it and test the "bike" side it should be open to run and grounded when shut off.

Hope that helps, but if it don't, hang in there! We'll find your spark ....

Great, thank you guys for the friendly welcome, this site and forums are by far the best I have come across so far in my motorcycle adventures. Thank you for all the resources, I will try testing those circuits and look for a ground
And report back!
Thanks again!

Howdy everybody! My name is Wes Abshire and I live in Boise, ID. I never was into bikes growing up, but recently I had a coworker offer to GIVE me a bike for free, plus help me fix it up! I kinda figured I better get better informed and learn to ride at that point. The bike he gave me is a 1970 Yamaha CT1 175. Frickin AWESOME bike! At least, I am sure it will be once we get it running.... We have most of the work done now its down to the wiring >:( Its definately been quite the project, but I have learned a ton and its been rewarding watching it move from a rust bucket covered in cobwebs, last started in 1980, into a sleek, freshly painted and reworked... anyway I will post up some pics as soon as I am not using the work computer lol

Hi all,
I am Tracy; I come in peace. I love old dirt bikes for reasons I do not fully understand..I am working on a '75 DT250 powered MX250 dual sport.

The power dynamo ignition is coming this week and I hope to bring it to life this weekend.

The 75 motor is replacing the MX360. Too much motor for me!! I am looking forward to more usable power.

The engine fit right in with only slight mods to the rear mount.

I will post pics when I get a moment.

Cheers,
Tracy

Sorry - I couldn't resist! Live long and prosper . . .

Howdy,
I am new to the Yamaha scene but not to the old bikes. I have had a few cb750s in the past. I just picked up a '74 100. Engine was stuck, but not anymore. As I hope to have this little guy going by the spring so i can take it out and have some fun. Love the site so far.

Have a good one!

AJ

To the site! Nice project!

neat project there!

I have a 1974 DT100A like yours but a lot more ratty.I plan to get started on it sometime in the future.parts still seem easy to come by for these and a lot less expensive than the larger bikes are.

New member, great to be part of this group. I am 57 years old so you know where I was when I was a kid, yes, admiring the bikes at the Yamaha shop and being told not to sit on the bikes. On Any Sunday came around and I was hooked. My father and brother both had Trailmaster 80cc's. Always love the Yamaha Enduros. I currently have a 68 Trailmaster 80, 1970 90 Enduro and a 1970 125 enduro, they are all keepers. I HAVE 2 1973 YAMAHA 125 ATMX's also. I restore bikes and race Vintage MX. Thanks for being here. Shawn

Hello out there! My name is john and I'm a newbie to the site. So far it looks real good but I'm still learning how to use it. I've been riding bikes since 1970. My first was a 350 Honda, then it was enduros and a 360 MX that was the fastest dirt bike I've owned by far! I now have a 1972 dt1e that someone stripped for dirt only, I've been riding out here in cal above 5k feet only, someday I might return it to orig. It looks just like my 74 MX, color and all. Nostalgia time haha. I will try to post some pics of the bike, the 250 dt1 soon. The ignition is unusual with cdi flywheel and points and condensor. Some how it works and runs real strong. I also have some 68 or 69 dt1 250 parts I don't need. Engine and trans both wheels , handle bars . I'm glad to be a member of this forum!