Do I need new coils?

[Guest]

Pretty sure I do. The primary resistance is good at 4.1 Ohms but the secondary are both open. Bike idles OK put poor rough acceleration and two of my plugs are black. Are new oem coils still available? or do I need to put something else on. I would like to keep it as stock as possible.

[BigD_83]

OEM coils can be had, but at a premium...mightn't be the coils failing, either. More likely to be the plug caps, or leads. If you need them, Dyna Green (3 Ohm) coils are a fraction of the cost, but might require reworking the mounting bracket a bit. You can't see them, so not being stock is probably less of a concern.

Which two plugs are black? 1/4 or 2/3? Each of those combinations runs off one coil

[RGM]

Took apart the plug caps, the 2-3 have these longer spring in them (bottom 2 ones in the pic) that when I took them apart I wasn't able to tell if the little disk was still holding the spring pulled out properly. The little white cylinder all measure about 11K ohms, I guess that what they used before resistance plugs? I am pretty sure it was 2-3 that were black, know it wasn't 4 should of been more careful taking the plugs out. So hooking the volt meter to ends of both HT leads I get 12K Ohms. I always use to measure coils between the HT lead and ground but maybe with this design that's not how it is supposed to be done?

[RGM]

Well finally got my engine running right. It was a combination of the plug caps and points. Now on to my brakes!

[RGM]

Decided to go for a rip up the Duffy. Bike ran awesome for 20km then started craping out. Itwas 2-3 again. I had changed the points as they were burnt and checked the capacitor which measured ok so I left it. I ha a new cap with me so changed it out as the points were sparking and she ran good again. The cap must of failed when warmed up