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Discussion Starter #1
Quick question, I have an 89 1100, will coils from a 2002 1100 work? I'm hesitant on the cheap new coils on ebay, the new oem ones are really expensive, and I'm hesitant one buying used ones that are 30 years old. Looking at the pictures they physically look the same, just didnt know of there was anything else I should be concerned about.
 

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I looked at some on ebay just for curiosity, and they look the same, if you can measure the resistance of the primary that should narrow it down. It looks like the number on the case is the same, so maybe perfect match.
 

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Discussion Starter #4
Looking at part numbers on the fiche the are the same up to 99, then the part number is different 2000 to 07. I'm wondering too if anyone has tried it. The one I'm looking at is on ebay so I cant really measure the resistance. They do look identical.
 

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If it helps with hunting the correct coils down the ones from the '98 to '03 750 ACE are also 30510-MM8-003.

If I was betting with your money, I'd bet that the 30510-MCC-003 is an interchangeable part and just a running production change over time.
 

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Discussion Starter #6
I found a cross reference for everything that part number fits and I'm going to take a chance on a set off a 2010 vtx1300. If this works I'll post up the reference I found as this really opened up the possibilities.
 

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If it helps with hunting the correct coils down the ones from the '98 to '03 750 ACE are also 30510-MM8-003.

If I was betting with your money, I'd bet that the 30510-MCC-003 is an interchangeable part and just a running production change over time.
Funny, I just checked mine today, Primary - 2.3 ohms, Secondary - 23 Kohms, Spark plug wires - 5.5 Kohms. FYI
Mother
 

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Many times they are the same basic parts but the bike model changes makes the spark wires longer, or the bracket different, and so they change numbers for that newer model.
 

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Discussion Starter #9
So I looked at the fiche for the 2010 VTX1300 and it actually uses one of each. I still haven't been able to figure out the difference other than the color, the MCC one is green and the MM8 is black. In the part description below there is an obvious price difference and the one my bike takes per Honda is the one that has (TEC) at the end. I actually have 2 sets of 1300 coils coming I got really cheap so I will end up with 2 of each part number. When they get here I am going to compare the ohm readings and see if there is any difference. It seems to me that since they still manufacture them and they are still currently used (1 of each part number) on the 2019 VTX1300 there has to be some sort of reason, plus the price difference.

So far it looks like 1987-2000 the 1100's use 2 of the MM8 coils. 2001-07 they use 2 of the MCC coils. The VTX1300 uses 2 of the MCC coils 2003-09 and 1 of each 2010 and later. I will update as I figure more out. The coils should be here next week.

COIL, IGNITION 30510-MCC-003 $57.99

COIL, IGNITION (TEC) 30510-MM8-003 $72.30
 

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I would think they are both made by TEC as the -003 part of the number is the same.
At least based on my understanding of the usual Honda part number breakdown.

It will be interesting to see what difference you find in the parts.
 

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I was going on the manufacturer case number MP10 and they are the same. Maybe a newer production run with different color plastic cases. ???
 

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Discussion Starter #12 (Edited)
Ok got the coils in today, not going to get a chance tonight to put them on. But I took some basic resistance readings. The coils on my bike measured 2.5 - 2.6 ohms on the primary side and about 23k ohms on the secondary side. Both are in spec. Both the new coils I got measured 2.5 - 2.6 on the primary side and vetween 22k and 22.5k on the secondary side. My wires measured 4.4k to 4.6k with the boot. The wires that came with the coils measured between 4.2k and 5.3k. I dont know what the spec is on the wire resistance. At least going by the resistance measurements the coils appear to be about the same.

Also here are some pictures, other than the color they physically seem to be the same. My old coils are in the right.
 

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The resistance is still in the ballpark on the end caps. They don't have a tight range. Just need approx 5000 ohms to suppress the RFI from the spark. They are just a carbon slug inside the plastic tube.

The wires may be solid like on my old bike. Should have 0 resistance but look for green corrosion in the ends where they screw on all the parts.
 

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If there was going to be a dwell time compatibility problem it would show up as a primary resistance difference.
I'm thinking the suggestion of color difference might be it!

There are all kinds of stories on replacement plug wires, but AFAIK all originals are 7mm copper core and combined with the stock ends it's the best choice.
 

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I would like to experiment one day and take out the resistance end caps. Since these are a dual plug system firing the same time, and each plug has a .035 gap, that is a total of .070 gap. Huge and needs all the power it can get.

Back in the 1980s Oldsmobile set their hot HEI ignition plugs to .080" for a while. They had runability issues so went down to .060". That .080 gap looked unreal.
 

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I would like to experiment one day and take out the resistance end caps. Since these are a dual plug system firing the same time, and each plug has a .035 gap, that is a total of .070 gap. Huge and needs all the power it can get....
The resistors in the end caps also provide current limiting, removing them would definitely provide a hotter (more current) spark. I'm not sure how it would affect the windings of the coil.
I don't think the spark gaps are additive like that though. But now that you mentioned it, I have been wondering about that also. Since I have an extra set of brand new coils I can sacrifice for the test so I may try that as my next project. I'm not really concerned about RFI though... Uh oh, I have another project...thanks.
Mother
 

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I am still trying to figure this ignition system myself.
Not exactly like the waste spark on a car since they fire 2 different cylinders.
But these fire 2 plugs in one cylinder, and fire each revolution since there is only 1 signal arm that goes by the pulse generators each crank revolution. I do believe that contributes to the pop on decel many of us have. Fire on the exhaust stoke .
So weird that with the dual fire system one plug fires forward, and the other reverse, from ground electrode to center electrode.



Here is another diagram on our engines=
 

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Well , firing on the exhaust and having it ignite indicates unburnt fuel in the chamber. As I indicated in my HSR42 post, that decel pop is now gone in mine. I always thought it was because of having 3 valves. "So weird that with the dual fire system one plug fires forward, and the other reverse, from ground electrode to center electrode."... I have never noticed that. My only thought would be that one plug is on one end of the secondary and the other plug is on the other end of the secondary which would be opposite in polarity, ie 180 degrees out.
Mother
 

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Worry about RFI, it can confuse the world the ICM lives in and I suppose possible cause damage.

The older VT750s and the ones from the VT750 ACE on are I believe quite a bit different when it comes to ignition.

The ACE ICM is pretty smart it has one pickup and counts pulses and fires from 2 nubs on a 9 nub reluctor ring the geometry of which is shared by a bunch of unrelated Honda bikes.
For the 750 it chooses pulses from nubs 7 & 9, on a un-offset crank VT1100 8 & 9 and a inline 2 or 4 CBR or CB nubs 3 & 9, all dictated by cylinder angle and crank layout.
This is why the Stock ICMs are bike model specific even if the reluctor layouts are not.

The twin plugs on the shared coil seems to work fine in the Shadow application and is obviously cheaper to produce while getting most of the benefits of a twin plug head.

There are twin plug Ducati bikes that fire two plugs with a similar coil setup that have shown slight increases in power on the dyno after conversion to one coil per plug.
I fear there is no simple way to do this for a Shadow without ditching the ICM for an aftermarket unit.
Then the temptation might be to go to a coil on plug setup eliminating the high voltage plug wires entirely, if one could stuff the coils into the allotted space
 
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