[Need help urgently]

So I'm new here, been having issues with my bike for 2.5 weeks (no rides at all, feels like months ) and my parents said I should ask on a yamaha Forum.

Anyway, I recently went out to get some petrol, and about 20m away from the station I lost all power and had to push it, I thought "Oh well, ran out of petrol", Filled up, keys in, started it...

Except it wouldnt start, I tried choke on, choke off, neutral gear, 1st gear+clutch, everything, still no avail. It does start (after a lot of hard work) and If I dont slip the clutch to keep it at 7k or more it stops and doesnt start, even when I do this it's hugely jerky. Its not out of water, or 2 stroke oil, chain is correct tension. Its a TZR 50 Btw.

Any help much appreciated; I'm forgetting what its like to get my leg over.

yes, new spark plug - fwiw, i dont like champions

[Clymer or Haynes?? Thanks.]

Tried to search for this. Prefer actual book-in-hand, rather than download. For 78 XS400 2e.

Is one or other preferred; seems that the Clymer is more year and model specific and am

leaning to that (both even better). Thanks.

i own both clymers and haynes, but the latest project DT250 has me laughing my tail off looking in the haynes - no instructions are offered for testing coils, condensers, etc, because the operation calls for a piece of "specialized equipment", a multimeter!!!!!!(no one is suspected to own such a device)-- (3 USD at harbor freight)

[magneto diagram 1975 DT250]

The source coil for the ignition should be grounded at one end and seperate from the lighting coils. Sme with the lighting coils, grounded at one end.

thanks for the reply, thats what i thought- i have to wonder why Yamaha sent the source coil ground thru the lighting coil before it could get to ground , it sure does look stock ,with the braided cloth insulator on the coil to coil jumper, nonetheless, i found a NOS source coil on ebay , mine is pretty compromised,the clear sprayed on insulation has flaked off the wires in many places , and an area of winding that was hit and shorted , i suppose there is a preferred polarity in the source coil that i will want to adhere to, (stock), when installing the new one, another problem id found was the point wire needs to run alongside the cam , it did, and rubbed against it, and rubbed thru its insulation, (*probobly the biggest, or only, problem in this resurrection), grounding the point wire- i sure will have a nice spark when this is assembled- think ive had this bike 30 years

[magneto diagram 1975 DT250]

just wondering if anyone studied (and made a drawing) of the wiring under the flywheel - one thing i found while looking it over is one wire from the source coil goes to the condenser, and the other one is soldered to a jumper wire to the lighting coil,- is this correct? i need some basic theory -one end of the source coil is grounded and the other end goes to the condenser, ? all 4 of the leads coming out of the lighting coil (which i wont need) are continuous to ground- why is the source coil hooked to the lighting coil? (with the short heat insulated jumper)