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1980 Honda Cx500c
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10 Posts
Discussion Starter · #1 ·
Hey folks. I’ve been browsing through the forum and haven’t found anything about my specific problem. Anyway here it is. The bike is fully custom built 1980cx500c cafe/bobber. The electrical system runs off of an m.unit. The ignition system is a 12v Hall effect unit from RaeSan. The reg/rec is a ricks one suitable for a lithium battery. The battery and the reg rec are brand new and the stator is fine. All checks have been done to confirm. After charging the battery fully I can ride for about an hour before the battery light on my gauge turns on. When turning off my headlight the charging system seems to charge the battery back up to get the battery light to go off. But it would take a pretty extended period of riding to fully charge the battery back to full. I’m wondering if the headlight is too much for the charging system and is slowly draining the battery as the charging system can’t keep up with the load? The current headlight is a halogen bulb. The headlight and housing are both after market. I am wondering if changing to an LED Bulb with lower wattage would possibly fix this problem. Or If the problem has to do with something else entirely. Any thoughts on the topic are greatly appreciated. Thanks!
 

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'84 CX650E that is evolving into a GL500
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I know little about lithium batteries and even less about the M unit so I can't help you if your problem is one of them. But there are lots of bikes with more or less stock wiring that have lithium batteries with suitable reg/recs, Rae-San ignitions and 55/60W halogen headlights (if you are running an 80+W one that could be the problem) and as long as you don't run a lot of other electrical loads they keep the battery charged just fine.

You say "the stator is fine" but how did you determine that?
Did you disconnect it from the reg/rec and measure the resistance between each pair of yellow wires? (should be a couple of ohms)
How about measuring between each yellow wire and ground? (should be infinity)
What voltage did you measure between each pair of yellow wires with the engine running?
If you had a regular battery and the original reg/rec I would ask you what the voltage is at 2500RPM with the headlight on (should be 14-15V). I think that's what your lithium battery setup should be too but if I'm wrong someone will correct me.

BTW: I missed this when you joined so welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable (not to mention what was altered or overlooked when it was modified) so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
 

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Registered
1980 Honda Cx500c
Joined
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10 Posts
Discussion Starter · #3 ·
I know little about lithium batteries and even less about the M unit so I can't help you if your problem is one of them. But there are lots of bikes with more or less stock wiring that have lithium batteries with suitable reg/recs, Rae-San ignitions and 55/60W halogen headlights (if you are running an 80+W one that could be the problem) and as long as you don't run a lot of other electrical loads they keep the battery charged just fine.

You say "the stator is fine" but how did you determine that?
Did you disconnect it from the reg/rec and measure the resistance between each pair of yellow wires? (should be a couple of ohms)
How about measuring between each yellow wire and ground? (should be infinity)
What voltage did you measure between each pair of yellow wires with the engine running?
If you had a regular battery and the original reg/rec I would ask you what the voltage is at 2500RPM with the headlight on (should be 14-15V). I think that's what your lithium battery setup should be too but if I'm wrong someone will correct me.

BTW: I missed this when you joined so welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable (not to mention what was altered or overlooked when it was modified) so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
Yea so I checked all the checks you mentioned above with the stator and they were all within spec. I’ve done these checks with the engine in and out, running and off. I’ve purchased a lower wattage halogen for now until my led bulb arrives in the mail. But I’m suspecting the 90/100 watt bulb that was in is my problem. I’ll let you guys know what I find out once the new bulb is installed. Thanks for letting me know to set up my profile correctly. I’ll get that taken care of. I just suspect the headlight Bc while riding down the road if I turn off the headlight, which I did trying to save as much power from the battery as possible to get the bike home,the lighting on the gauge brightened up instantly. But I’ll let you know what I find I’m on the way home from the store now
 

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1980 Honda Cx500c
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10 Posts
Discussion Starter · #4 ·
Yea so I checked all the checks you mentioned above with the stator and they were all within spec. I’ve done these checks with the engine in and out, running and off. I’ve purchased a lower wattage halogen for now until my led bulb arrives in the mail. But I’m suspecting the 90/100 watt bulb that was in is my problem. I’ll let you guys know what I find out once the new bulb is installed. Thanks for letting me know to set up my profile correctly. I’ll get that taken care of. I just suspect the headlight Bc while riding down the road if I turn off the headlight, which I did trying to save as much power from the battery as possible to get the bike home,the lighting on the gauge brightened up instantly. But I’ll let you know what I find I’m on the way home from the store now
Also my other electrical loads include a digital temp gauge, led tail light and tag lights and led blinkers front and rear. The headlight is the only lighting that’s not led. (That will soon change to full led)
 

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1980 Honda Cx500c
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10 Posts
Discussion Starter · #5 ·
Also my other electrical loads include a digital temp gauge, led tail light and tag lights and led blinkers front and rear. The headlight is the only lighting that’s not led. (That will soon change to full led)
Also everything rubber, rad hoses, bearings, bushings, wiring, everything has been replaced with brand new parts. Tires have about 50 miles on them. All gaskets and o rings have been replaced in the engine/cooling system. Even the engine bolts are brand new. The bike has been basically fully restored from the ground up.
 

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1980 Honda Cx500c
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10 Posts
Discussion Starter · #7 ·
Also everything rubber, rad hoses, bearings, bushings, wiring, everything has been replaced with brand new parts. Tires have about 50 miles on them. All gaskets and o rings have been replaced in the engine/cooling system. Even the engine bolts are brand new. The bike has been basically fully restored from the ground up.
[/QUOTE
Sounds like you've been thorough.

And like the headlight bulb is probably the problem.
ok so I did another AC voltage test with the bike running at 2500 rpm. Turns out I have a bad stator. It put out around 18v for 2 phases and only 5v for the 3rd.. so would anyone happen to know the best replacement stator? I’ve removed the pick ups and wiring from the engine due to going to Hall effect set up. Only need the stator with the three yellow wires. I’ve been think the Ricks one would be best but it’s pricey. Maybe someone will have a better suggestion
 

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Premium Member
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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12,452 Posts
Custom Rewind, but they're more pricey. Also, probably the last stator you'll buy for that engine.
 

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Premium Member
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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12,452 Posts
That's them. I think they've changed ownership and expanded. Looks like a new facility in the video.
 

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Super Moderator
'84 CX650E that is evolving into a GL500
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18,925 Posts
ok so I did another AC voltage test with the bike running at 2500 rpm. Turns out I have a bad stator. It put out around 18v for 2 phases and only 5v for the 3rd.. so would anyone happen to know the best replacement stator? I’ve removed the pick ups and wiring from the engine due to going to Hall effect set up.
Shouldn't that be more like 70-80 VAC? (You did have your meter set to AC volts, didn't you?)

If you only need the charging part you want one made for a GL500 or CX/GL650 (often referred to as a G8 type). It has the same footprint as the CDI stator but since it doesn't need to give up space to the CDI parts there's enough room for more charging windings so it is rated at 252W (compared to the CDI stator's 150W).
 

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That's them. I think they've changed ownership and expanded. Looks like a new facility in the video.
Gary Frye was the previous owner and looking at the contact info email address it shows vfrye so maybe spouse/family member took over?
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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12,452 Posts
Gary Frye was the previous owner and looking at the contact info email address it shows vfrye so maybe spouse/family member took over?
Gary has been ill for a long time. I wouldn't be surprised if family members have taken over the operation.
 

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1980 Honda Cx500c
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10 Posts
Discussion Starter · #14 ·
Shouldn't that be more like 70-80 VAC? (You did have your meter set to AC volts, didn't you?)

If you only need the charging part you want one made for a GL500 or CX/GL650 (often referred to as a G8 type). It has the same footprint as the CDI stator but since it doesn't need to give up space to the CDI parts there's enough room for more charging windings so it is rated at 252W (compared to the CDI stator's 150W).
Yea I figured that out after doing some research. I drove home from work total of 12mi and my battery voltage stayed at 13.3 when I got home so maybe a LED bulb will help for now until I get the new one
 
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