Killing coils?

[Retired 18E]

Greetings all,

Well the earlier problem was solved with a new battery, but now there are bigger fish to fry.

Specifically, it seems she is frying coils for the top two cylinders. At the start of this season the top left was not firing, I picked up a new Banshee coil and this did fix the problem. She was running great. Now suddenly neither of the top cylinders are firing! She still starts, but there is no blue smoke coming from the top two exhaust, in fact it is just cool air pulses.

Maybe I've somehow offended the entire board, I don't know but my last post received zero replies. I wouldn't post something if I didn't think someone could lend some knowledge. So please fellow owners and members, any ideas??

Thank you, Max

[bolly]

check for actual spark on both wires?

carbs splotlessly clean?

autolube pump correctly adjusted?

[2smoke]

Its not you. No one participates anymore.
Unfortunately you are going to have to pull the gas tank back or off.
Then check the plugs for spark. Check wiring connectors are still in place.
Lastly check the coil for continuity.
Maybe the mounting bracket and bolt for security to the frame.
Maybe the plugs are just wet.

[silverstrom]

Are you just assuming it's a coil issue? Have you metered the coil? Have you replaced wires and caps?

If it is electrical and is affecting only part of the system it is likely a connection problem.

Yamaha used the same coils in many bikes and I have plenty of them in use here. I've never seen one fail. Bad connections, wires and caps, yes, but not a bad coil.

And, as Colin has noted, this place is very quiet for some reason.

[Retired 18E]

Thanks for the advice. I went out and checked the coils, and it seems I was wrong and you were right. The primary read ~.5 ohms and the secondary read ~ 10KOhms. I've checked and double checked all the connections, but have not had a chance to start her yet. ( I work the graveyard shift + and sometimes come back just burnt.)

One other lead though, maybe. Mr. Wilson that did my engine rebuild told me to run Br8EG plugs post break-in. But I still have B8HS in. The major difference between the two plugs being that one is obviously a resistor plug, and the resistor plug reaches deeper into the cylinder by 5mm. The "E" is 19mm and the "H" is 14mm. Perhaps I really, really need the right plug here? My step-son and I checked for spark prior to my original post, he said he saw some, but that it was very weak.

Thanks again, any more thoughts are still very appreciated.

Max

[Bengt Weil]

Are you sure Bill suggests using "EG" suffix plugs instead of "HS"? Be sure to double check with him BEFORE installing the "EG" plugs or trying to start it with "EG" plugs.

In NGK language:
"H" = 1/2" reach thread
"E" = 3/4" reach thread

[vma500]

For checking the coil output u need to pull the cap off and put a spare coil in and hold to the chassis to see if they spark well ,plse use gloves when doing that

But cold exhaust air rings a bel in my head ,airleak on intake or reeds not closing well !

[silverstrom]

Using the non-resistor plugs will also cause electrical interference. Bet that when you start using the proper BR9HS plugs the bike runs better.

[2smoke]

Using the non-resistor plugs will also cause electrical interference. Bet that when you start using the proper BR9HS plugs the bike runs better.

Yes BR9HS
Use what yamaha says.

Not much to add till you pull your plugs.
Except, dont check your coil with the method above!! lol.

[Twinsport]

... Bet that when you start using the proper BR9HS plugs the bike runs better...

But make sure that you dont run resistor plugs and resistor caps.

/Steen

[silverstrom]

But make sure that you dont run resistor plugs and resistor caps.

/Steen

Why not?

At a minimum you need resistor plugs or resistor caps, but ideally you should use both.

[Retired 18E]

Thank you all for your assistance. I emailed that question to Bill prior to my original post as I could not locate the instructions he sent me with my rebuilt engine. But that's what he said in reply "BR8EG" which I noted was going to go deeper into the cylinder. It seems the collective wisdom is to go with the BR9HS. Fine by me, I'd just like to get those top two cylinders firing again.


Max

[WVWRZ500N]

Max,

Sorry I lead you the wrong way on the plugs the other day. My mind is on this Pike's Peak motor and the BR8EG is what we use in it.

The plug I recommended post break in is the B8HV.

At a minimum you must have either a resistor cap OR resistor plug. If you double up it is of no concern but you must have at least one resistor to eliminate electrical 'noise' in the system.

Clean ALL electrical connections from the ignition switch to the coils. I've had CDI connections that kept individual cylinders from firing.

Again, sorry for the misinformation.

Regards,
Bill Wilson
Wilson Performance
Lee's Summit, MO
http://www.wilsonperformance.net" onclick="window.open(this.href);return false;
Member RZ500 Owners Group #573
816-377-3185
WVWRZ500N@aol.com

[Twinsport]

...Why not?

At a minimum you need resistor plugs or resistor caps, but ideally you should use both.

Energy is lost every time you run the current through a resistor. Therefore ideally you want no resistor. That might however introduce electrical noise into some of the electronic circuits that we have, and for that reason we use either resistor plug or resistor cap. Having both resistors yields maximum loss of ignition energy. This energy is what you want the most of with fouled or wet plugs, as enough energy transmitted to the plug creates a spark, even under difficult circumstances. This is why you would want as little resistance as possible, while still keeping electrical interference under control.

/Steen

[silverstrom]

I have resistor plugs and caps in all of my bikes and have never had any issues. The people I know have both and haven't had any problems. NGK only uses a 5K ohm resistor in their plugs and caps. Any healthy ignition system is easily able to deal with this. If adding an extra 5K is causing enough current loss to affect your ignition system, well, then you have a bigger problem somewhere else.