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BF100 owners with points and condenser

M

mroman59

Member
I found a condenser that can be used for the obsolete one. The original has a capacity of 0.24uF, according to my manual. I called a manufacturer of condensers and they looked up one that had a similar capacity. They have many, but gave me one that is sold in Advanced Auto Parts. It is G610 and has a capacity of 0.21 to 0.25 uF. I dont know which vehicle it was made for but it is manufactured under the name of BWD. Now at this time I don not know if it will fit under the Cam Pully, but if not , it can be mounted outside and run the wire through the case. I believe you will have find a way to ground it properly.
 
Thanks for the tip mroman59! That will likely help quite a few out of a jamb if they can find this thread.

I'm going to write it down in my shop notes so I can pass it on any time someone asks.

GOODONYA!
 
The G610 condenser is small and can fit under the cam pulley, however the bracket attached to it prevents it from fitting. Later I will see about removing the bracket if I can and then use a clamp and screw it down with the mounting screw. For now, I used a straight metal bracket from hardware store, 1/2" by 2", with 2 pre-drilled holes. I drilled out one of the holes the size of the 10 mm bolt that threads into the side of the cylinder/engine block. The bolt I used is the one on the side that has a wire clamp for the wire running from the cam pulley to the coil. I used the other pre-drilled hole of the bracket to mount the condenser. The wire of the condenser is plenty long to reach under the cam pulley and connect to the points. The wire from the condenser sits on top of the rubber holder and below the wire clamp plate. I plan to modify the mounting of the condenser/coil wire at the cam pulley because I am afraid that the cam pulley could rub on the wire as it spins. For now, I am just testing. I used a zip-tie to hold the two wires together and helps to keep the condenser wire down.

I will update this tread and let you know what happens when I test it. I also called Honda to find out if the 30500-ZV8-G01 coil can be used instead of the 30500-881-000, since it is obsolete. The told me No because the one was made for a CDI unit. I asked them for the primary and secondary resistances.

000 = primary 0.56 ohms +/- 10%, secondary 8 K ohms +/- 20%
G01 = primary 0.35 - 0.43 ohms, secondary 23.1 - 34.7 K ohms

I found a man on the internet who put a G01 in place of the 000 and he said his engine runs good. I am trying to contact him to see if it is still running using this coil. I am not sure if Honda gave me the correct values for the G01 because they sent me a shop manual diagram and the photo did not match the coil being sold. I will call and ask them again. Some technicians from other companies are telling me that it could work.

The values for the G01 , is the closest dual spark 6 volt coil that I have come across. Most being made today are for motor cycles that have a higher resistance value. I am trying to find out more to determined if it can be used.

I also found a carburetor and fuel pump that are made by Honda and work, according to a Honda dealer, even though these are not considered replacements by Honda. The dealer said they mounted to the BF100's to verify they can be used. If anyone is interested in that information, just ask and I will get the part numbers.
 
I have some shop notes I wrote down awhile back. I don't recall the details but I have crossed out the spec for the coil secondary (8k ○hms) and replaced it with;

31.5k ○hms for BOTH breaker point AND CDI ignitions.

I also have crossed out 0.58 ○hms for coil primary resistance and have written in;

1.5 ○hms for breaker point coil

And;

0.8 ○hms for CDI

I seem to remember that I did this back when there was some discussion here about this subject. I KNOW that I took these readings with a Fluke 87 dvom from two GOOD running engines I had at the time.

I concluded that the empirical readings were close enough to one another that the coils were both the same.

I wish now I had taken the time to swap them engine to engine to see how they performed and possibly written down any numbers on the housings. Oh well, water under the transom now.

I do think though that, to your endeavors, that the G01 will work for the older engine but point and condenser life may be effected due to a possible higher firing voltage. Just a guess.
 
your 31.5K secondary resistance is close to what was given for the G01, 23.1-34.7 I am still not sure if Honda gave me the correct part values. I will call today.

your 1.5 ohms for the primary is much higher than the G01, so that would be to high to use IMHO. The coil you were taking notes on may not be a good choice since it is so high, however you dont know which coil your were taking notes for. Do I understand correctly?

The G01 coils primary is in close range and lower than the 000, but the secondary resistance is too high.

Which resistance value of the G01 coil are you thinking that will cause condenser and points life to be shortened, primary , secondary or both?

thanks,MR
 
Sadly, my memory isn't keen enough to be sure about which coil was on which engine, breaker points vs. CDI.

One thing I forgot to say earlier is that my shop manual only gives one secondary resistance spec and that was 8k ○hms. I am curious as to where you got the specs for the G01?

As far as my assumptions about the higher resistance coils creating problems with points and/or condenser that's all that is, assumption.
I just assume that the increased resistance, wheather it be in either case, primary or secondary, would create a "hotter" spark due to elevated voltage needed to induce current flow.

I could be all wet here, not being an electrical engineer. And, I recall the wise words of a way smarter guy than me that tuned winning sprint cars for a living...."anybody ever tells you that he knows exactly how magnetos work, is a dang lier"! ;>)
 
LOL

G01 specs : primary is 0.35 - 0.43 , secondary is 23.1 - 37K ohms. I called Honda today to verify these values.

One thing I forgot to ask them about the G01 was is it a 6 volt or 12 volt system. If it is 12 volt than that will increase those values when putting it on the BF100 6 volt system.
 
I think you're mixing up the charge system with the ignition system. The charging system was an option that uses a coil under the flywheel to supply ac voltage to a bridge type rectifier to convert to dc volts. The coil is designed to put out ac volts at full throttle that tops out at around 13 volts dc on the output side of the rectifier.

I don't know of a 6 volt charge system. The only ones I've come across have been 12v.

The ignition coil uses a separate coil of its own and thus the two systems don't connect to each other at all.

The ignition coil has one lead grounded so it only produces half cycle current flowing to the CDI through a diode. So, it is a "pulsating" dc voltage that increases with engine speed. I don't remember exactly but I believe the volts can go well above 60vdc inside the CDI....maybe higher. I can't find a specification for that in my manual. I know I have measured it before but never wrote it down.

I know hondadude knows exactly what it is. Maybe he'll chime in.
 
Last edited:
Sorry if I confused you. On my ignition coil (30500-881-004), located outside of the flywheel, 6 volts is stamped on the side. I asked technicians and the said that means that it is a 6 volt system. So I was looking for dual 6 volt coils that would meet those primary and secondary resistance values given to me by Honda.

After searching, I did find several coils advertised as 6 volt (verses 12 volt) being sold by none of them had the resistance values that matched. I found some 12 volt dual spark ignition coils, technicians were telling me that even though the resistance values would match, it would give me a higher value than what theirs is rated at and therefore could cause damage to the points and what else I dont know.

I am familiar with the charging coil under the flywheel and I did check the output using my volt meter one day, while the engine was running and though I can remember the reading, the battery was reading at or above 13 volts.

Since technicians were telling me that there are 6 volt and 12 volt ignition coils, I was inquiring about which one the 30500-ZV8-G01 was. Now since I was talking to ignitions about a coils they were advertising with spark plug wires I do believe they were giving me information about those and not about a charging coil. With that said, I dont know which the G01 is at this time and when I asked a seller of this coil, the stated there was no 6 or 12 volt stamped on the side of it like my 004 had.

At this point, I am not sure what the difference between a 6 volt vs a 12 volt if the resistance values are the equivalent. There is no battery used for starting and no alternator for charging the battery. The technician made me feel that a 12 volt coil resistance values would result in a higher voltage even though the resistance values are the same. Some are telling me different.

Regarless the G01 resistance values dont match the 004 for the secondary. One tech told me this is OK as long as both coils are made for the same systems (i.e. 6 v or 12 volt). So the question remains, is the G01 a 6 volt or 12 volt or does that not matter.

If anyone can shed more light on this subject please chime in.
 
I have done some cross reference checks for you If it was my motor i would use the 30500 zv8 GOI and connect the black wire to earth .
 
Tegweni, thanks for this information. I do know what the resistance values are for the 30500-ZV8-G01 and since the primary resistance is in range it should work. Its the secondary resistance value that is too high and technicians are saying that could cause a problem down the road. Specifically, I think they were saying it could damage the points. This point I am not sure about. Also, I do not know if this coil was made for a 6 volt system or a 12 volt. I am not sure if my system is 6 volt or 12 volt either, I just know that the coil in the motor has a 6 v on it. I also know that there are dual spark coils sold that are advertised for either 6 volt or 12 volt systems and the technicians say that you cant put a 12 volt in a 6 volt system, even if it has the same resistance, also because it can cause damage to the points. This information was given to me by various technicians that I spoke to of manufacturers of coils.

With that said, if the 30500-ZV8-G0I will work, the question is which black wire are you speaking of? There are three black wires that are mounted to the terminal of this coil, i.e. the 1) kill switch, 2) points & condenser and 3) wire leading underneath the flywheel which should be the primary coil.

If you are speaking of a black wire (negative) on the coil there is none according to the photos of those sold. Its appearance is exactly like my coil (30500-881-004. there are two spark plug wires, high tension terminal for the wires descried above and the high tension terminal where the mounting screws go through.

When you say you did some cross reference checks, what were those. According to Honda, this coil can not be used or should not be used.

Thanks,
MR
 
jgmo said:
I think you're mixing up the charge system with the ignition system. The charging system was an option that uses a coil under the flywheel to supply ac voltage to a bridge type rectifier to convert to dc volts. The coil is designed to put out ac volts at full throttle that tops out at around 13 volts dc on the output side of the rectifier.

I don't know of a 6 volt charge system. The only ones I've come across have been 12v.

The ignition coil uses a separate coil of its own and thus the two systems don't connect to each other at all.
Click to expand...

I have been reading info on the internet regarding 6 volt and 12 volt and I understand regarding the charging system. So since this is not a batter start engine, then the use of a 12 volt coil should not matter as long as you are not trying to charge a battery, correct? Or does it. Every time I read about the difference regarding charging, they then switch to conversation about damage to points if you use a 12 volt in place. this I do not understand if your coil, made for a 12 volt system has the same resistance values as the coil made for a 6 volt system.

I did find some site talking about 6 volt to 12 volt change overs and the need for a ballast resister. Again, this seems only relevant if you are charging a battery and running accessories.

Now since the charging coil and the rectifier are involved here, does that mean you would need to add a ballast resister to get the correct DC output at the battery and/or prevent damage to the charging coil and rectifier?

thoughts are appreciated, however my job today is to find out the correct readings of the coil in my motor before I try to find a replacement.
 
All I can say is that the charging system and the ignition systems on these (if I am clear on what you actually have) small displacement, twin engine outboards, do NOT intersect.

As to ballast resistors, I'm only aware that, for decades, they have been used in 12 volt automotive ignition systems to lower the voltage going to the coil to prevent it from overheating and failure. The START circuit in these systems allows 12 volts to the coil for increased spark during cranking. Then when the spring loaded ignition switch is released and allowed to go into the RUN position, it diverts the feed to the coil through a ballast resistor (or, through a segment of resistive wire) to lower the voltage going to the coil to around 7.5 volts or just over half of vehicle charging volts. I can't speak to very late model systems as I have been away from the business for some time.
I think, but don't know, that today's coils are more robust and can take a steady, ground switched, 12 volt supply but don't quote me on it.

That's my story and may be actually MORE than I know ;>)
 
I agree that the charging system and the ignition systems do not intersect and that is one of the reasons that I feel if I find a coil made for a 12 volts system should be ok to use in place of mine ( as long as they are of similar resistance values). Again, I am assuming that my engine is a 6 volt wiring system.

Here is a link to what I was reading regarding to changeovers. One of the reasons people do it on their old motors is because that they can no longer find parts for their motors and the newer parts are made for 12 volt wiring system. Now this becomes more important when the vehicle is running a lot of accessories.

https://www.fillingstation.com/articles/6volt.htm
http://www.yesterdaystractors.com/articles/artint8.htm

My main concern is the talk regarding to causing damage to the points and condenser which are not part of the charging system. Since my points and condenser are obsolete then I dont what to take the chance just yet of of using a coil made for a 12 volt system.

I know Pertronix makes a product designed to allow someone to get rid of there points and condenser. I am inquiring about that also. If that is so, perhaps one can use just about any coil with these products. The cost could be much cheaper than trying to buy expensive Honda parts. I am seeing dual spark coils very cheap and if I am able to eliminate the only part , that is also obsolete, then that could be a blessing.
 
I have a 1971 100hp Johnson that runs on a 1974 Toyota corolla ballast resistor and coil the resistor is connected in series between the ignition switch and coil .
 
Tegweni said:
I have a 1971 100hp Johnson that runs on a 1974 Toyota corolla ballast resistor and coil the resistor is connected in series between the ignition switch and coil .
Click to expand...

I contacted Pertronix by email and asked them if they make anything that will work to replace my points and condenser. I am waiting for their reply. I have a feeling that they may not have anything the Honda BF100 from my initial web search.

As far as your ballast resistor is concerned, did you convert your system to a 12 volt system or did you just install a coil that was of different specifications than the original?
 
It came out from new with a amplifier points and condenser the amplifier packed up so i switched over using the Toyota coil it does the same job, the trick is you have to connect the ballast resistor [its a porcelain one it takes the heat off the coil without it it wont work because the coil will get hot] in series before the coil .
 
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