Ignition coils

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PaulGreen
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Ignition coils

#1 Post by PaulGreen » Wed Dec 05, 2018 4:52 pm

Hi,
The upper ignition coil isn't giving a spark and my multimeter shows it out of spec.

Gen Yam replacements are still available for £120 but there are alternative non-gen ones available for around £30.
I'm struggling to see why a pattern part would be inferior, can anybody help me please?

The lower genuine Yam coil is still ok, but the pattern replacement upper has failed. Looking for opinions on pattern vs genuine.

Thanks,
Paul.

PaulGreen
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Re: Ignition coils

#2 Post by PaulGreen » Wed Dec 05, 2018 4:55 pm

Just found what I was looking for further down the page.....

silverstrom
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Re: Ignition coils

#3 Post by silverstrom » Thu Dec 06, 2018 1:05 am

You mean the last sentence, where you answered your own question? :mrgreen:

And for what it's worth, the same coil is used on the TZR250, TDR250, RD350 YPVS 1986 and up, and others.

PaulGreen
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Re: Ignition coils

#4 Post by PaulGreen » Thu Dec 06, 2018 10:26 am

I realise that I kind of answered my own question a bit.

I'm not trying to do this on the cheap but I don't like spending extra money unnecessarily. Having a pattern coil fail like this isn't really a fair test as the bike's been stood for a few years.
I guess what I'm really wondering about is does having "Yamaha" printed on the side make it worth 4 times as much? Or make it 4 times more reliable?
I recently bought my boy some new football boots and he assures me that he plays better now that his boots have an "Adidas" name on them.....

Cheers,
Paul.

PaulGreen
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Re: Ignition coils

#5 Post by PaulGreen » Fri Dec 14, 2018 2:06 pm

Ok, I went for a pattern part and the resistances are out of spec according to the manual. In fact they are exactly the same as the pattern part that i thought had failed.
I now can't find where I saw the gen Yam coils!

I've seen reference to Banshee coils working but I'm a bit dubious as the two that I now have that don't work were labelled specifically RD500LC.
I've asked one supplier - RDLCcrazy - for the resistances before I buy yet unsuitable item.

Is anybody else using Banshee coils on their 500?

Thanks,
Paul.

PaulGreen
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Re: Ignition coils

#6 Post by PaulGreen » Fri Dec 14, 2018 4:43 pm

Found this part number 3LC-82310-01, for a 350 ypvs. Could somebody confirm that it's ok please?

Thanks,
Paul.

silverstrom
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Re: Ignition coils

#7 Post by silverstrom » Fri Dec 14, 2018 4:52 pm

Pattern coils are meant to work for the YPVS 350 and TZR250 as well as the RD500. The resistance checks will be close to all of those, but perhaps not necessarily the same as the manual, which is only valid for Yamaha coils.

What exactly is the issue? Do you have no ignition at all with one coil? If that is the case, swap the coils and see what happens.

Keep in mind that the resistance checks in the Yamaha manual will be with the high tension leads installed. If you are testing without the leads installed you will get different values. Plug caps off, but high tension leads attached to the coil.

As I have already mentioned, the same coil is used for many bikes, including the RD500, TZR250, YPVS 350 1986 and up, etc. There are differences in the required resistance values in the manuals because the bikes have different length high tension leads.

For a coil not to function properly the resistance would have to be very obviously out of tolerance. It would be so obvious there would be do doubt.

I have never seen a Yamaha coil fail. The high tension leads yes, but never a coil as used on the bikes mentioned above, and I have had many here. Any issues are typically related to poor ground/earthing.

silverstrom
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Re: Ignition coils

#8 Post by silverstrom » Fri Dec 14, 2018 4:55 pm

PaulGreen wrote: Fri Dec 14, 2018 4:43 pm Found this part number 3LC-82310-01, for a 350 ypvs. Could somebody confirm that it's ok please?

Thanks,
Paul.

That's a Banshee part #.

If you want 1986 + RD350 YPVS it's 1UA-82310-50. 1983,1984 and 1985 RD350 coils are a completely different unit and will not work.

Those part numbers include the high tension leads and caps.

Feel free to PM me if you need help with this.

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Re: Ignition coils

#9 Post by PaulGreen » Fri Dec 14, 2018 5:12 pm

Thanks silverstrom,
The issue with the upper coil is that it sparks rarely, and when it does it's a very weak spark. This would explain why the bike runs on 2.5 cylinders.
When I put the good coil on the upper cylinders then I got a good spark, tomorrow I'll try yo start the bike with the coils swapped and see if it runs on the rear cylinders.
All resistance checks I've done have been directly across the spade connectors or across the bare ends of the HT leads and have given consistent results. I have 3 spare coils, one of which is clearly no good, two others are out of the Yam spec giving 4 ohms , from memory, I have eliminated the plug caps as an issue.
I've ordered an in line spark tester that you mentioned on another thread - I didn't know they existed!

I intend running a tap through the mounting point to ensure the threads are clean and giving a good earth, although I'm sure this wouldn't be a problem anyway. I'll also inspect the wiring harness around there, it's very cramped so I'm going to ensure that I'm not making/breaking a poor connection when I'm moving things around in there.

Thanks again,
Paul.

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Re: Ignition coils

#10 Post by PaulGreen » Sat Dec 15, 2018 1:49 pm

Well Ive ruled out the ign coils, swapped the two over tonight and kicked it over and still running on the fronts.
When I kicked it over with all plugs removed the sparks from the uppers seemed stronger and more consistent. And it did run on all four for a short while.

I'm not missing anything obvious here am I? there's no other system on the bike that distinctly separates the motor across front and rear?

Carbs off again next I guess.

Cheers,
Paul.

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Re: Ignition coils

#11 Post by silverstrom » Sat Dec 15, 2018 4:44 pm

Perhaps it's time to do a compression test on the rear cylinders.

Perhaps the gap on your pick-up coil is too large?

Maybe an ignition timing issue?

The RZ500 motor is basically two separate motors geared together.

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Jeff B
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Re: Ignition coils

#12 Post by Jeff B » Mon Dec 17, 2018 3:21 pm

Bad ground can mess with ignition. I had that problem. The symptoms were a little different though.

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phildu31
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Re: Ignition coils

#13 Post by phildu31 » Wed Dec 26, 2018 9:18 pm

Just seen your post.
Still issues with rear coil ?
If yse, can you test your CDI on another bike or test another CDI on your bike ?
Each coil is powered by a different circuit in the CDI.

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Re: Ignition coils

#14 Post by silverstrom » Wed Dec 26, 2018 10:37 pm

phildu31 wrote: Wed Dec 26, 2018 9:18 pm Each coil is powered by a different circuit in the CDI.
That I did not know Philippe.

That could be very useful here. That would have been good to know 10 days ago. It would really suck if he has been doing all that work, pulling cylinders, etc, for a defective CDI.

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phildu31
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Re: Ignition coils

#15 Post by phildu31 » Thu Dec 27, 2018 7:45 am

To be precise, I never opened a CDI box but I suspect there are different output transistors for the 2 coils.
So the 2 orange output wires in the CDI.
I never heard of any CDI failure on a 500, contrary to the YPVS box.
But that is a track to not discard.
A test that could be done is to swap these 2 orange coil output wires on the CDI, maybe this can be done in the round connector otherwise it would require some cut and weld.
With this swap if motor runs on the rear cylinders then the CDI is defective.
Otherwise it will only prove that the CDI is ok.

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