old timer (with CB400A knowledge and tips)

old timer

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Jun 3, 2020
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Location
40 Barker Lane Waverly Ohio 45690
Tomorrow is my 79 th year on this old earth. I am starting to fell every one of them so I closed the shop . I will finish the CA 95 but its my last one. Its been a good run but its time to slow down. For those who Have A models I thought I would leave a few notes.

All the A models , the 400 and 450 models use the same change switch, change relay , side stand switch ,cdi , stator and torque converter. They also share the kick start inhibitor. The part numbers dont match but its the wire connectors that are different they use the same components . I put a CM change switch on a CB just rewired it.

There are safety features on the A models that other bikes dont have.

Tom , If you think it might be worth writing down the information on the A models I will be happy to do it.

Jim , I have a change switch, change switch relay and CDI from a running A model. If you would like them to play with send me your address and I will mail them to you.

Bill H
 
Bill, the older I get the more I understand where you must be at this point. I'm honored that you came over with us from the other site and helped a lot of people here with your A model knowledge and general knowledge as well. Only you know best if it's time to close up the shop. We'll be here, and you're always welcome to pop in and say hello or comment on any post you feel like you can offer some help to. If there are other tips on the A model that you want to share with us other than above, feel free to add them to this thread.

Thanks for all your insight and knowledge over the years Bill.

Edit: And yes, Happy Birthday! :party: :birthday:
 
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old timer

Be well, Bill… wish you all the best! Thank you for all you’ve shared.

EDIT: How’d we miss that?!
HAPPIEST BIRTHDAY!

Tom - 1982 CM450E
 
HAPPY BIRTHDAY
There comes a time for everyone to kick back and say I've done enough and I'm going to enjoy myself doing something different. As we progress with age we find more physical limitations, some we can ignore and others we can't. Just because the shop is closing up that doesn't mean you can't visit with us and throw some advice when you feel like it. But now you're going to make me pay attention to all the nuances and differences with the A model.
PM sent
 
Thanks guys. Jim I will ship next week. I plan on staying around just to keep in touch.

I will put a few things together on the A models and post next week.

The owner of the CA 95 said he would have the parts here this week end . Will see.

Bill H
 
When Honda built the A model they they built in some safety features to protect the general public. They didnt want the motor to start in gear or for the motor to run with the side stand down when in gear. This was done by adding a change relay transistor to control the CDI. the transistor in this case is used as an off-on switch. The change switch is mounted on top of the upper case and under the right carb. The change switch is activated by the shift cam mounted on the shift drum. The change switch looks like a rear brake switch and works about the same. In neutral the change switch is fully extended and the change switch is off. the change relay transistor is on. and the indicator lights are off. When you shift into gear the change switch is turned on and the relay transistor is turned off. The indictor lights will tell you what gear your are in.

In neutral the change relay transistor is on. The starter circuit grounds thru the relay and the starter will work, the motor will run with the side stand down. The SCR 2 gate in the CDI is grounded thru the relay and the motor will fire at 7.5 degrees BTDC. In gear the relay is off. The starter circuit is no longer grounded and the starter will no longer work so you cant start it in gear. The side stand switch when lowered in gear with the motor running will ground out the thru the SCR 1 gate in the CDI to stop the motor from running and the bike from moving with the side stand down. The SCR2 gate is no longer grounded and the motor will fire at 15 degrees at TDC to increase the idle to compensate for load from the torque converter.

I probably didnt explain this very well so any questions -fire away. Next post I will give some trouble shooting tips.

Bill H
 
Happy birthday Bill. Please keep the "A" information coming!

Sent from my Pixel 4 using Tapatalk
 
Happy birthday, Bill. Your feedback on my threads and those of others regarding the 400s and A models has been invaluable to me. Appreciate you.
 
Thanks guys. Your A has been running fine but today you turn on the key and the neutral light doesnt come on or the first gear light is on and the stater doesnt work or you shift to first and the neutral stays on you may have a problem with the change switch . The change switch does two things. it will light up an indicator light and tell you what gear you are in and most important it turns the change switch relay transistor off and on. Plunger fully extended the change relay is on and when put in gear the plunger is moved onto the switch turning the relay off. If you think the problem is in the change switch you can remove it and look for a groove in the bottom of the plunger. sometimes the shift cam will cut a groove in the bottom of the plunger. This will give you a false reading . Check to see if the plunger move freely in and out of the switch. Take an OHM meter and set it on continuity ,place the + on one of the wires and - on the body of the switch and you should get a 0 reading. slowly move the plunger into the switch and you should get a reading. If you have continuity , the plunger is ok and you have the correct 10 mm washer between the upper case and the switch then switch is probably be ok. The 10 mm washer sets the clearance between the switch and the shift cam.

Change switch relay transistor will be covered in the next post.
 
A lot of this will be repetitive. The change switch relay can be tested by removing it and using the FSM you test it with an OHM meter. If the neutral light is off and the starter doesnt work you can test the relay by removing the LG/R wire from the relay and jump it to the G/R wire on the magmetic switch. Key on push the starter switch and if the starter works the relay is probably bad. If the starter doesnt work treat it like a reg motor and try to found out why the starter doesnt work

With the motor in neutral the change switch is OFF and the change switch relay transistor is ON.

With the transistor on

The starter circuit is grounded thru the relay

The ST terminal voltage is nearly equal to the ground potential. No current flows through the side stand switch and the motor will run with the side stand up or down.

The the SCR2 gate in the CDI is grounded and the 7.5 signal is sent from the fixed pulser to the SCR 1 gate and the motor will fire at 7.5 DBTDC.

With the motor in gear the change switch is turned ON and the switch relay is turned OFF.

The starter circuit is no longer grounded.

When the motor is running and the side stand is lowered the current flows thru the side stand switch to the SCR1 gate in the CDi and shorts out the ingition condenser and stopping the motor. This will keep the bike from moving with the side stand down.


The SCR2 gate is no longer grounded so the fixed pulser sends a 15 degree signal to the SCR1 gate and the motor will fire at 15 DBTDC. This will increase the RPM to compensate for the load from the torque converter.

Clear as mud aint it.

The CDI cant be tested.

Thats pretty much how it works . any Questions please ask.

Bill H
 
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