Coil question

[Czakky]

Seems the old girl (71' R5) is losing power. Last summer she ran better on 145 mains, I tried 150s and it ran the same. I went through the ignition, checked points, timing etc.

Two things I've noticed. When shooting the right cylinder with a timing gun it seems like it wasn't firing as consistently as the left...? Not sure if that's possible but I tried again when the bike is cold and it seemed better. As I type this I'm remembering that the points were absolutely not arcing at all, which I'm not sure I've ever seen perfect points like that. Not sure what that says.
The other thing is with fresh plugs it runs great.

So I'm looking at the coils, particularly the right side. Do coils get weak with age when hot? Or are they a worky, no worky type deal?

Thanks for any help

[m in sc]

they go with age. replace both, and the condensors with new

[Frank B]

It's been said that the stock style replacement coils from Economy Cycle are really good and provide a strong spark.

https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/electrical-ignitions-lighting/ignition/replacement-ignition-coil-kit-rdr5yds67-coils-caps-wires-for-rdr5yds67/

[Organicjedi]

Bad coils can act up when hot too.

[Czakky]

Thanks for the replies.

Points and condensers are new last year. The coils are what look like silver Emgos from previous owner. I'll put my order in with economy.

[Frank B]

Ditch those emgo coils, high failure rate with those..

[SUPERTUNE]

Yes, I've have the same issues before. Coils will go with age and heat.
Your on the right track.
Chuck

[Czakky]

 

[Plasticman]

+1 on replacing the condenser first, then the coils.  I've had two condensers quite and only one cylinder failed, not both.

Rob

[Czakky]

As far as condensers go I replaced those last winter, although this winter I had a pretty (for me) in depth overhaul on an old Guzzi and wouldn't you know two bad brand new condensers... Put the 40+ year old condensers on and she's never missed a beat. Your mind goes to some dark places when you spend that much time bringing an old machine back to life and after a few hundred miles it starts running like crap.

So to recap my issue, a loss of some power and the points look like they run clean (no sparking/arcing). They are gapped and timing was checked dynamically.

Either way new coils on the way from Economy Cycle.

[quocle603]

I had issues with my coil. Searched all around for this issue, checked my fuel, petcock, timing, condensors, points...turns out that I just needed new coils. It was a nightmare to fish around for because I thought it was a fuel issues at first, then thought my timing had slip, but it was just the OEM coils.

Changed them out and never looked back. A good way to know in the future is that if your bike runs well at cold start and your bike only starts to fire on one side when it hot. I also noticed that when it was higher RPMs, my bike would not fail but once I got to the lower rpm, there wasn't enough juice to ignite the fuel. GOOD LUCK!

[Czakky]

If the mailman beats the thunderstorm by enough time I might be able to report how the new coils perform shortly.

[m in sc]

piece of advice. on t he new coils, put a dab of silicone on the metal connections on the body of the coil to insulate them. 

[Czakky]

I didn't catch your post M, but I had the same idea anyway.

She runs a bit better now. Just the same as it did last summer. Thanks for verifying my hunch. 

The only mod I made over the winter was adding clear oil injector lines. They have been solid every time I looked at em. Except today, the right side is getting an air gap of about an inch long. I'm going to have to see about the check valve in the pump....

[2t Fan]

which is the most powerful coils available for points set up?

can we use DYNATEK 5 OHM DC10-1 coils on points/TCI RD ignition?