Coil question

SUPERTUNE · June 01, 2019, 08:55:17 PM

Yes, pretty much that's available for old points ignitions unless you want to go the old car coil route.
I still have the Dyna S pickups and run the DC3-1 3 ohm coils.

Czakky · June 02, 2019, 10:10:25 AM

So this is wandering off topic. But it went from minor to major it appears.

Went for a ride yesterday and after priming my oil pump to fill that one inch air gap on the oil lines off I went. Running as good as she ever has then after about four miles I tried to whack open the throttle in a high gear. It bogs out like it's not getting gas, I look at my fuel lines everything looks fine. Now I'm bee lining home at a low throttle and things get worse and she dies. My oil lines are halfway empty.... plenty of oil in the tank. I rebuilt this pump a little over a year ago and it has at least 1500 miles on it since being rebuilt. Phone my wife and she delivers a bottle of oil. I drain the float bowls and mix my tank at 32:1 or better. On with the fuel tap and kick, kick, kick, nothing. Keep in mind the bike has sat for at least twenty minutes at this point and was only warm.
It finally starts and runs good for a few miles then dies right before my drive way. Now it sits and I'm a bit gutted.
When it died the first time I kicked it a couple times and it definitely didn't feel tight. FWIW.
Did she seize? Twice? Why would this happen after new coils?

Barrie · June 02, 2019, 12:45:02 PM

What is the bike?

SoCal250 · June 02, 2019, 02:19:10 PM

Quote from: Barrie on June 02, 2019, 12:45:02 PM
What is the bike?

Quote from: Czakky on May 29, 2019, 09:19:51 PM
Seems the old girl (71' R5) is losing power.

Organicjedi · June 02, 2019, 02:23:46 PM

Going back to the basics here- how do the plugs look?

Bad coils can foul plugs. Did you change them when you changed the coils?

Did you eliminate the ballast resistor? Your new coils won't need it - not sure if R5s had that or not.

SoCal250 · June 02, 2019, 02:35:15 PM

Quote from: Czakky on June 02, 2019, 10:10:25 AM
Did she seize? Twice? Why would this happen after new coils?

Have you pulled the headpipes and looked at the pistons through the exhaust port? A sieze will be evident there. If it did sieze I don't think your coil issue is related. It sounds like you may have had an oil or fuel starvation issue. Since the exact problem really isn't known you will want to start checking things to determine exactly what happened, and then once you know the issue (siezure, weak/bad ignition, etc.), then try to determine why it happened. Hopefully it's something minor like an ignition issue that's easy to resolve and not a siezure.

Check the plugs as mentioned above. Also, when was the last time the timing was set/checked? You may want to verify it's still correct, especially if you see anything abnormal on the piston skirts.

Czakky · June 02, 2019, 05:01:47 PM

@barrie. I modified my avatar

@organicjedi. I did not change the plugs I was going to do that but never got around to it.
I thought that R5s didn't need an additional ballast resistor...?

@socal250. I can pull the head pipes out again. I just did a leak test a couple weeks ago when I was first having running issues.
Timing was checked at the same time.

I will check plugs soon. I think I have to not look at her for a while.

Thanks for the help guys.

Czakky · June 02, 2019, 07:50:29 PM

So the oil pump is definitely not pumping. Which is awesome!

That doesn't explain why it died/seized the second time with a tank full of pre-mix. Unless pre-mix effects jetting that much.

Plugs didn't look oil fouled. Left was a bit wet, but it started up and idled.

I still have more investigating to do, but what should I do with an engine that seized? Will it kill the bottom end? Did it already? I don't hear any piston slap.

SoCal250 · June 02, 2019, 10:59:26 PM

Quote from: Czakky on June 02, 2019, 07:50:29 PM
So the oil pump is definitely not pumping. Which is awesome! That doesn't explain why it died/seized the second time with a tank full of pre-mix. Unless pre-mix effects jetting that much.

Plugs didn't look oil fouled. Left was a bit wet, but it started up and idled.

I still have more investigating to do, but what should I do with an engine that seized? Will it kill the bottom end? Did it already? I don't hear any piston slap.

Ouch, sorry to hear that! :(

Sounds like you found the problem. No oil = no lubrication = VERY bad. This results in excessive heat, and metal vs. metal direct contact. This causes a seizure.

Why it siezed again after you stopped and let it cool off?...
Once it's seized, a subsequent siezure is likely since the conditions are the same (or nearly the same) and the piston skirts and cylinder walls have been scuffed. Your switch to pre-mix was likely too late to do much good since the majority of the damage was already done.

It's time to pull the barrels to check the extent of the the damage.

Jspooner · June 02, 2019, 11:12:22 PM

Quote from: Czakky on June 02, 2019, 07:50:29 PM
Unless pre-mix effects jetting that much.

Premix requires richer jetting, I'm not sure how much richer but oil displaces fuel, so more oil means less fuel which mean its going to run leaner. But as Russ said, the damage was probably already done. As far as how much damage, well, that depends on how long you ran it. Sounds like quite a ways so you should split the cases and check out the crank, etc.

SoCal250 · June 02, 2019, 11:33:53 PM

Quote from: Jspooner on June 02, 2019, 11:12:22 PM
Quote from: Czakky on June 02, 2019, 07:50:29 PM
Unless pre-mix effects jetting that much.

Premix requires richer jetting, I'm not sure how much richer but oil displaces fuel, so more oil means less fuel which mean its going to run leaner. But as Russ said, the damage was probably already done. As far as how much damage, well, that depends on how long you ran it. Sounds like quite a ways so you should split the cases and check out the crank, etc.

Good point. Going to pre-mix leaned up the mixture on a possibly already damaged engine.

quocle603 · June 04, 2019, 06:18:23 AM

Pull off the top end, inspect the damage. If it's not too bad, then hone it out and get new a piston and rings. If it is bad, then just get a whole new top end. Might as well change out your gaskets while you're at it. Good luck!

Czakky · June 04, 2019, 10:27:38 AM

That's pretty much the plan Quocle. How well does a crank survive an oil related seizure usually?

Jspooner · June 04, 2019, 10:38:52 AM

Quote from: Czakky on June 04, 2019, 10:27:38 AM
That's pretty much the plan Quocle. How well does a crank survive an oil related seizure usually?

Its a gamble, normally the pistons would seize first and then that's usually then end of it and the crank would/could/should survive, but it sounds like you kept riding it so who knows, I would not take that gamble, I would just split the motor and check out the crank........better safe than sorry.

SUPERTUNE · June 04, 2019, 10:50:12 AM

Quote from: Czakky on June 04, 2019, 10:27:38 AM
That's pretty much the plan Quocle. How well does a crank survive an oil related seizure usually?

Take the top end off first and post or send me pics, unless you burned a hole all the way through the piston... yes, do a full teardown.
Minor seizures don't hurt the crank. fix topend and put back on.
Chuck

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