Ignition Diagnosis for CB/CM 400/450 and CB450SC manual trans 1978-1986 - Page 3
Page 3 of 8 FirstFirst 1 2 3 4 5 ... LastLast
Results 21 to 30 of 74
Like Tree7Likes

Thread: Ignition Diagnosis for CB/CM 400/450 and CB450SC manual trans 1978-1986

  1. #21
    Junior Member SoapyCoyote's Avatar
    Join Date
    Apr 2017
    Location
    Utah
    Posts
    15
    Here's a quick video of the current state of my electrical on my 1980 Honda CM400T

  2. #22
    Junior Member SoapyCoyote's Avatar
    Join Date
    Apr 2017
    Location
    Utah
    Posts
    15

  3. #23
    Junior Member SoapyCoyote's Avatar
    Join Date
    Apr 2017
    Location
    Utah
    Posts
    15
    Latest news with my 1980 CM400T ignition: Followed to instructions here and found that everything tested good except for my coil. Followed the instructions about the GM coil mod here http://www.hondatwins.net/forums/64-...d-writeup.html and now I am getting a good healthy spark on both plugs!!! Thank you guys and thank you Jim! Now my question is, as you can see in the video I have this three way switch up by the steering column and I'm not sure what it is for, I suspect it is for a kind of substitute for "turning the key in the ignition to the on position" or off position, because there is no key on this bike as received from P.O. I also think that my starting switch button on the right handlebar is bad. What should I do? And what should I do to get all of my connectors connecting happily without being intermittent? I now know that Dielectric grease can be a bad thing, so I haven't used any of that yet. But these connectors are subject to some harsh environments and the elements and this bike is from 1980 so yeah I would like to help all of my connections. Thanks you guys again! So grateful for this goldmine of information!

  4. Remove Advertisements
    HondaTwins.net
    Advertisements
     

  5. #24
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    21,614
    Hamburger helper has been at work on this bike. SO
    Ignition switch/circuits
    OFF position, Black w/White is connected to Green to ground the CDI turning it off. Red has battery power. No other wires are powered up
    ON position: Red has battery power, Black, Brown and Brown W/White have power. Black w/White is NOT connected to Green allowing ingition to work
    Park position: Red has battery power, Brown has power. Nothing else is powered. Black w/White is connected to Green to turn the CDI off
    Need to sort this section first before going after the starter switch/solenoid since the Black ignition switch wire powers the starter circuit.
    Dielectric grease is your friend, use it liberally on all connections.

    Sorry for slow response, been dealing with minor health issue for the last week
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 survivor restoration


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

  6. #25
    Junior Member SoapyCoyote's Avatar
    Join Date
    Apr 2017
    Location
    Utah
    Posts
    15
    Thanks Jim! Turns out it is just a two way switch, not a three way. Sorry about that. Dielectric grease? Ok! good to know.
    Sorry to hear about your having health issues, hope you feel better soon.
    As for myself, I caught the flu and have been unable to work on my bike much the past few days.
    Hopefully I can spend some time on her these next couple days. Today I was able to get it to spark on both plugs!
    Next I drained out the old gas and put in fresh gas and tried to start her up. She acted like there was no gas at all.

    I also noticed that the rubber boots around the carb weren't secure at all so I wonder how much engine damage that caused?
    I wonder if this engine needs to be replaced or rebuilt. Anyway, I don't know how smart this was, or if I caused more damage
    by doing this, but I dribbled a teaspoon of gas into each carb opening, shorted the starter solenoid to get it to turn over
    (there is no kick start) and it sounded like it wanted to catch for a few revolutions. This gave me hope! But now I come seeking advice.

    What should I do? Seems like maybe an engine
    compression test would be good to do? Don't want to rebuild the carbs if the engine needs to be replaced. Not sure exactly
    how to do an engine compression test correctly... pour a teaspoon of motor oil down each spark plug hole first, and disconnectfurther questions
    the primary side of my new GM coil, then crank it over until the needle on the compression gauge tops out?
    I am looking for 185 psi right? If I don't get that, should I check my valves? Or just get a new engine/rebuild this one?
    Also, should I move my future questions about compression tests to the Engine discussion part of the forum now?
    Any advice/links to that part of the Forum are greatly appreciated! Thanks!


    Thanks again Jim. Feels like the electrical on my bike is almost 100% now thanks to this Sticky!
    Last edited by SoapyCoyote; 04-21-2017 at 07:37 PM.

  7. #26
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    21,614
    Compression test is a definite thing to do. Yes, 185 is spec but they will run ok down to the 150 mark and sort of ok down to 135 which is really low.
    I would adjust the valves first, if anything make them loose on the adjusing. Yeah, they be a bit noisey at first but they will reseal better if there any issue there. After a 100 miles or so once she's running then readjust to spec.
    Compression test is done with both plugs removed, throttle held wide open, choke off and cranked until the gauge stops rising. 1/2 teaspoon of oil added after the first test if the compression is low, same procedure. If the readings are higher then it's the rings, same means valves which is pretty unusual for these engines.
    From here I'd say let's get a new thread going in the Engine section so this sticky doesn't get too cluttered.
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 survivor restoration


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

  8. #27
    Junior Member SoapyCoyote's Avatar
    Join Date
    Apr 2017
    Location
    Utah
    Posts
    15
    Thanks Jim! Did the compression test and started a new thread under "Engine Discussion" here's the link: http://www.hondatwins.net/forums/62-...tml#post646569

  9. #28
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    21,614
    OK, new specs for the stator tests.
    Pink to Green 129 Ohms
    Blue to White 84.2 Ohms
    Brown to Lt. Blue 203 Ohms
    New specs were obtained by testing 2 NOS stators, early version with the bullet connectors on the Blue & White connectors instead of the plastic plug in.
    The old specs should be considered the maximum resistance readings and the new ones minimum resistance
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 survivor restoration


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

  10. #29
    Member jnscott90's Avatar
    Join Date
    Apr 2014
    Posts
    43
    I've got a problem child, a 1983 CB450SC I've been working on for 3 years now. Finally thought it was road worthy after a few miles of riding around the block when all of a sudden she won't fire after being warmed up and parked for more than 15-30 minutes. This is frustrating. My buddy wanted to ride it after I let it sit for a half hour and it wouldn't start for anything. I've pulled the plugs during this phenomenon to study them, and sure enough it never fails after warming the motor up and letting it sit for more than 30 minutes you won't get it to start up again until tomorrow. The strange thing is it's never cut out on me while I'm riding and revs well past 5000rpm easily on the street. So. I started chasing electrical issues and came across this thread. My cheap VOM readings are as follows when I first started the motor and knew that it would run.
    Running: Coil Primary: 2ohms, secondary: 5,290ohms (btw I've got the GM coil mod), plug end caps: 5150, Stator advance pickup sensor: 137.5ohms, cdi pwr: 86.3ohms, primary pickup coil: 213, kill switch correct, alternator test: all connections at 2.2, ground test on alt: infinite ohms (assuming my harbor freight meter is a few ohms off)
    Went out for a ride and warmed the motor up for about 5 minutes and let it sit, motor off, for about 30. As expected, not a single spark. Tear the bike apart and start testing again and what I found was a similar range of ohms but a higher resistance when the motor is warm, except for the parts I've replaced: Not running, Coil Prim: 1.6, second: 5500, end caps:5030, stator advance pickup: 153.5, cdi pwr: 97, Primary pickup coil: 236, kill switch: infinite when "run": around 8ohms when "off" (key on), alt: 4.4, ground: still infinite. Is this common to have higher resistance as the wiring is subject to heat or is it all just one big electrical mess? Secondly, I know this test is used to determine by process of elimination a bad cdi unit. This seems like an obvious heat related problem as some old part (possibly the cdi) is not enjoying basking in the warmth of the recently ran motor, and my guess is that eventually the bike would shut down if left running at idle for 30 minutes (or leave me stranded somewhere), but I don't want to waste that much gas. Does anyone have any other suggestions for me? I thought about splicing and mounting the CDI to a different, less hot area of the bike as a test. Or am I chasing something that could be a timing issue as well?
    I appreciate your help!

  11. #30
    Super Moderator longdistancerider's Avatar
    Join Date
    Oct 2011
    Location
    Vancouver Washington (text 408-239-9580)
    Posts
    21,614
    I'm going to suggest using a different VOM, the HF units can be ok or they may not be.
    Right now your coil is too high in resistance hot or cold, it's puts extra load on the CDI unit.
    Your readings for the stator are out of spec cold and even further out hot.
    Jim O'Brien
    1979 CM400T "road bike" modified for travelling
    1978 CB400T1 restored
    1972 CL350 survivor restoration


    https://www.hondatwins.net/forums/22...d-attempt.html and https://www.hondatwins.net/forums/1-...r-attempt.html
    Road Trip https://www.hondatwins.net/forums/11...here-i-go.html or "where's Jim now?"
    Member Map https://www.hondatwins.net/forums/dcMembermap.php

Page 3 of 8 FirstFirst 1 2 3 4 5 ... LastLast

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

1985 cb450sc testong cdi

Click on a term to search our site for related topics.