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Discussion Starter · #1 · (Edited)
Hi everyone, I'm mounting my '73 cb450 cafe but there are a lot of electrical problem.
How can i do to test my ignition coils? is it possible to replace the wires? and it's ok a Tec FL705-12v-4Y like the photo?(it came from a cb500t).
It's possible to check if it makes the spark without the battery or with an old battery? in this case where can I connect the two black cables of the coils?
I have to change my stock battery to a lithium battery, do you know x-racer brand? I have to change stock rectifier with this type of battery? which I should buy?
Thankyou and sorry for all these questions :p
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Testing ignition coils can be done by running a wire from the positive terminal of the battery to the black/white wire for each coil. The blue or yellow wire then goes to the negative side of the battery. Disconnecting the blue or the yellow is what triggers the spark. Have the spark plug held against bare metal on the bike and you should be able to see the spark. Battery will need to be in the bike and fully connected.
 

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Discussion Starter · #3 ·
Thankyou for the answer, I still have to buy the battery as its original is gone and has 10.3v, for reasons of space I am forced to mount a lithium battery, can I mount it with the original rectifier?
 

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First of all, nice bike. Don't be intimidated by the wiring. Just take it one thing at a time. You are going to get a lot of answers and opinions. Some are going to contradict others. This is what I think:
Battery: A battery is required to make the ignition system work. It is possible to make it run without one, but it will not run well and it is challenging. This is best left to an expert. The best battery for these old bikes is an AGM. These play well with the stock (or modernized) charging system and are durable. You should have a float charger to go with the bike. That is a requirement from the time you buy the battery. I use a cheap Harbor Freight one and it is fine. I do not recommend a Lithium battery on these old Hondas. I use them with my RC models and I work for Boeing and know the details behind the Lithium battery fires on the 787. At best you will be buying more than one per season, at worst the bike will burn up. It is up to you.
Coil Testing: Wire the bike up and see if you get spark, by pulling the plug and turning the bike over with the plug laying on the head. It is that simple. The Honda FSM shows an elaborate test apparatus that simulates the points, power supply and has an adjustable gap. The specs are given in the width of gap the coil can jump a spark.
CB500T Coil: I don't see why it wouldn't work. The 500T and 450 DOHC ignition systems are similar. If it was me, I would want new coils, regulator, rectifier and lights. But that is just me.
 

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Discussion Starter · #5 ·
First of all, nice bike. Don't be intimidated by the wiring. Just take it one thing at a time. You are going to get a lot of answers and opinions. Some are going to contradict others. This is what I think:
Battery: A battery is required to make the ignition system work. It is possible to make it run without one, but it will not run well and it is challenging. This is best left to an expert. The best battery for these old bikes is an AGM. These play well with the stock (or modernized) charging system and are durable. You should have a float charger to go with the bike. That is a requirement from the time you buy the battery. I use a cheap Harbor Freight one and it is fine. I do not recommend a Lithium battery on these old Hondas. I use them with my RC models and I work for Boeing and know the details behind the Lithium battery fires on the 787. At best you will be buying more than one per season, at worst the bike will burn up. It is up to you.
Coil Testing: Wire the bike up and see if you get spark, by pulling the plug and turning the bike over with the plug laying on the head. It is that simple. The Honda FSM shows an elaborate test apparatus that simulates the points, power supply and has an adjustable gap. The specs are given in the width of gap the coil can jump a spark.
CB500T Coil: I don't see why it wouldn't work. The 500T and 450 DOHC ignition systems are similar. If it was me, I would want new coils, regulator, rectifier and lights. But that is just me.
Thank you for your very clear answer, i know which is the problem with a lithium battery but i have only 13x11x8.5 (cm) of free space, it was an error at the design stage :(
Lights are new and i will buy new regulator and new rectifier.
Unfortunately to do the tests and turn it on I need the battery, I'm very undecided about how to solve this situation because the lithium battery scares me and I can't find an acid battery smaller than the original.
Fortunaly the electrical system is in good condition and easy to assemble.
P.S. sorry for my bad english :lol:
 

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Deso, no worries about your English. I understand fine and it is much better than my Italian. The article listed below includes the charging requirements for Lithium batteries. The 450 DOHC charging system does not meet these requirements. If you find a solution for this problem please share it with us. The proper cell type to use is an A123. A total of eight cells should be used. two parallel banks of four cell in series. Using a conservative 3.2 volt cutoff voltage, the batteries would operate in the range of 12.8 to 16.4 volts. Some kind of a voltage regulating system would need to be installed. Otherwise the battery would be damaged during charging and the light bulbs would not last due to the high voltages. There are Lithium motorcycle batteries being marketed, but they are for more modern motorcycles that have more sophisticated charging systems. You may want to reconsider redesigning your battery compartment.

Do you not have the stock battery tray? It looks like you are using the stock airfilters. There should be room for the correct battery. I would suggest looking at the build log for my 450K5. I made a new wiring harness, upgraded to the stock regulator and rectifier to a modern type. I also installed the PAMCO ignition along with higher energy coils. My first lead acid battery lasted one season. The charging system provided too much current and boiled the battery electrolyte and damaged it. I went to a higher wattage (45W) headlight and installed a AGM. It is working very well.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
 

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Discussion Starter · #7 · (Edited)
The battery tray is stock but with my new saddle i have less space for the battery. I need a non standard battery like H:12,5 x L:13,5 x W:8,5 (cm), I have seen AGM battery but they all have length equal to 150 cm.
which is the minimum amperage for a cb450? I think mine with LED tail light, new front light and new arrows require less energy. I could also use electric starter sporadically if is necessary.
I did the spark test with the old battery and it's ok.
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In photo: Yuasa YB9-B 12V 9.5Ah 115A (from a Piaggio Vespa scooter)
 

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It looks like you have welded the battery tray in place. Does it sit higher in the frame than the stock position or is the seat lower? Can you extend the bottom of the battery tray to make the battery sit lower in the frame? Are the airfilters in the correct location?

Motorcycle batteries are rated in amps per hour. It is a measurement of how much current the battery can produce over a given amount of time. The stock CB450 DOHC is rated at 12 amps per hout (usually shown as 12AH). This is also known as cranking power, or cold cranking power. Once the engine is running it will run off the alternator above about 3,000 RPM and need the battery below that. A smaller battery willo work for that.
AGM batteries have a higher cranking power than an old fashioned lead acid. This means they can be smaller in physical size. Also an AGM battery has a slower self discharge rate so they last longer when they are not on a tender. These reasons make it OK to go to a smaller amp hour rating. The only problem you may run into with a smaller battery is the electric starter may not have enough energy to start on a cold day when the battery is low on charge. You can look for an AGM that will fit. You just need to make sure the positive and negative terminals are in the same general area as the stock battery and the cables will fit.
I havee heard of people on this site who have successfully batteries as small as 6 AH. I cannot tell you how well the electric starter worked. I'm sure if the bike was well tuned it would be OK if the engine was warm and the battery healthy. Cold day starts may require the kick starter.
You should go online and search for a smaller AGM battery that will fit in you modified battery tray. Here is an example of a AGM for a CB200 (1974) that might fit. It is 9AH: https://www.batterymart.com/p-yb9-b-sealed-maintenance-free-agm-battery.html
 

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I do not recommend a Lithium battery on these old Hondas. I use them with my RC models and I work for Boeing and know the details behind the Lithium battery fires on the 787. At best you will be buying more than one per season, at worst the bike will burn up. It is up to you.
I'd like to present a dissenting opinion on this one.

LI-ION go in all my bikes; both vintage and modern.

There are definite caveats for using them, but as long as you understand and accept the limitations, they're a good bet.

First, LI-ION does not play with with higher voltage levels. 14.5V is the max, otherwise damage will usually occur. The higher the voltage, the more damage and the quicker it will happen. In order to combat the voltage limitation, a modern regulator/rectifier is a must. The $35 unit we sell on our website was designed specifically to allow LI-ION use on the old Honda twins. The internal regulator is set to 13.9V, which in the real work usually ends up being in the low 14s.

The other concern about LI-ION is having the voltage go too low. When you over discharge LI-ION batteries, they start to dissolve their own electrodes. This causes gradual battery failure as the capacity of the battery will begin to lessen. On a Honda twin, you are running off of the battery when you're idling because the alternator doesn't put out enough electricity to keep the bike running until you get the revs up. So you need to understand that with a LI-ION battery, you can't spend a lot of time idling. Don't idle the bike for 15 minutes in your drive and try to avoid heavy traffic. Again, our R/R was designed to help alleviate this problem (it has low internal resistance and charging can often come on as early as 2000 RPM), but the only fool proof way to keep your LI-ION battery in good health is to avoid idling the bike as much as is possible.

Provided you stick to those rules, LI-ION does offer a good number of advantages over lead acid technology. It can be mounted in any orientation, including upside down. Obviously, the size and weight are a great advantage as well. One overlooked benefit of LI-ION technology is the extremely low self-discharge rate. LI-ION batteries only lose two or three percent of their charge per month. This means my bikes can sit all winter without a trickle charger and they still start right up in the spring (or even summer). When well-cared for, LI-ION batteries also last much longer than lead acid. My oldest LI-ION battery is six years and going. I have yet to experience a single failure.
 

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Sonreir,
Does your system provide a low voltage cutoff for the battery? Running the battery below 2.8v per cell will permently damage them. For best life they should be kept above 3.2v per cell. On a motor bike low voltage can occur. If the bike is properly functioning this should not happen. Lithium battery fire danger is over stated. It does happen, but either the charging system fails of the battery is defective. On the charging system side, either the regulator would need to fail to a short to direct full regulator voltage to the battery of the rectifier fails all full AC to the battery. Or a direct short accross the battery. Trust me, they get very hot very fast. The 787 now carries two battery fire proof boxes. They would make a nice air tight stove in your living room.
 

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^^^I second that from Sonreir. My bike has been apart since last August and my Lithium-ion battery has been sitting disconnected all that time, and the test button on it shows all 3 LEDs (full charge) to this day. Before the aftermarket voltmeter died, it was running around the limit of the battery (14.3 to 14.5) while riding above 3000 rpm and in 600+ miles of use, was not negatively affected. I'm probably going to try disconnecting the yellow and white (possibly put a switch inline between the two) because I'm running an LED aftermarket headlight and even with the headlight switch in low beam position, which makes no difference to my single-brightness headlight, it still ran the same voltage. I'm sold on the 4AH lithium I bought that only weighs one pound and is 1/3 the size of the 12AH lead acid.
 

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Discussion Starter · #12 ·
^^^I second that from Sonreir. My bike has been apart since last August and my Lithium-ion battery has been sitting disconnected all that time, and the test button on it shows all 3 LEDs (full charge) to this day. Before the aftermarket voltmeter died, it was running around the limit of the battery (14.3 to 14.5) while riding above 3000 rpm and in 600+ miles of use, was not negatively affected. I'm probably going to try disconnecting the yellow and white (possibly put a switch inline between the two) because I'm running an LED aftermarket headlight and even with the headlight switch in low beam position, which makes no difference to my single-brightness headlight, it still ran the same voltage. I'm sold on the 4AH lithium I bought that only weighs one pound and is 1/3 the size of the 12AH lead acid.
what is your impression about 4Ah battery? do you use electric starter?
 

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Sonreir,
Does your system provide a low voltage cutoff for the battery? Running the battery below 2.8v per cell will permently damage them. For best life they should be kept above 3.2v per cell. On a motor bike low voltage can occur. If the bike is properly functioning this should not happen. Lithium battery fire danger is over stated. It does happen, but either the charging system fails of the battery is defective. On the charging system side, either the regulator would need to fail to a short to direct full regulator voltage to the battery of the rectifier fails all full AC to the battery. Or a direct short accross the battery. Trust me, they get very hot very fast. The 787 now carries two battery fire proof boxes. They would make a nice air tight stove in your living room.
Our regulator/rectifier does not provide an automatic cut off and I am unaware if this is a feature in any others.

The (only) battery brand we carry, EarthX, has that feature built into the battery, however.
 

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^^^I second that from Sonreir. My bike has been apart since last August and my Lithium-ion battery has been sitting disconnected all that time, and the test button on it shows all 3 LEDs (full charge) to this day. Before the aftermarket voltmeter died, it was running around the limit of the battery (14.3 to 14.5) while riding above 3000 rpm and in 600+ miles of use, was not negatively affected. I'm probably going to try disconnecting the yellow and white (possibly put a switch inline between the two) because I'm running an LED aftermarket headlight and even with the headlight switch in low beam position, which makes no difference to my single-brightness headlight, it still ran the same voltage. I'm sold on the 4AH lithium I bought that only weighs one pound and is 1/3 the size of the 12AH lead acid.
If you're running with a modern regulator/rectifier, I would just leave it bridged. Back in the day, the point of having the separate windings was because voltage regulator technology wasn't what it is now.
 
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