1974 RD250 - Coil Issue?

[BlueR32]

Hi Friends,
Need some of your collective expertise on this one. The motor sits in this project which some of you may remember:
https://www.2strokeworld.net/forum/index.php?topic=3909.77

I've been road-testing lately and I've got this odd behavior when revs hit 6000 and above. The motor just dies. I've been through fuel delivery, carb jets and everything checks out to spec. Timing also in spec. Points, plugs and condensor are all new. Once in a rare while she will rev past 6000 but it's rough and only in lower gears. I'm beginning to suspect coils and/or charging under load. Any ideas?

[m in sc]

if it was a coil or condensor it would drop one cyl, not both. look at wiring and connections. switches, battery connections,  etc

[JKV45]

As noted - check your battery connections and voltage. You should get 12.7V or more before starting.

I've had older bikes that would start and run with a weak battery, but would not rev out.

[BlueR32]

Thanks for the suggestions. I did a temporary direct feed off the battery to the coils and that made a huge difference. She will now rev past 6K in all gears, albeit with a bit of a stumble around 6-7k. So I guess I've got a voltage drop somewhere in the ignition circuit. I plan to do the relay mod so I can get power directly from battery to coils.

I am suspecting the stumble might be fueling: I'm running DG chambers, Uni foam filter and Y-boot. Pilots are 30, mains are 130. One of the needles is pitted. I think I might need larger mains for this setup and replace the pitted needle.

[m in sc]

yeah go up to like 190s and work diwn