electrical problem cb175?????
Close

electrical problem cb175?????

This is a discussion on electrical problem cb175????? within the Technical forums, part of the Caferacer.net Forums category; I was out running the bike around for a few minutes the other day and it took a crap on me. It started when I ...

Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92

    electrical problem cb175?????


    I was out running the bike around for a few minutes the other day and it took a crap on me.

    It started when I went to take off in first and put load on the bike, it wanted to fall flat on it's face. ran fine, then started loosing power, aggressive popping under throttle, and would have a tough time restarting. Then when I would get it fired back up, there would be little to no then tons of power, or very sluggish...no smooth power delivery.

    xtremly erratic with no consistency.

    I don't think it's fuel delivery or any air intake issues. I did not have the bike fired up for that long, so I don't think it was overheating.

    sounds like shit as well, not as crip as it did a few miles back. I think it might be electical due to the unpredictable nature. would a bad coil cause this, or do they fail consistently?



  2. #2
    Senior Member bmartin's Avatar
    Join Date
    Feb 2008
    Location
    Palmyra, NY, USA.
    Posts
    2,740
    You might want to take a compression test on the cylinders before you start chasing an electrical problem. It is a quick test and will tell you if your motor is A-OK. If the compression test is good, then move on to check your fuel system (dirt in your carb or fuel filter). Again this is a quick test. After you have eliminated motor and fuel - then start looking at your electrical starting with your timing (points??), sparkplugs and finally coil.

    From the description of your problem, any or all items listed above could be the cause. Problem tracking is a process of elimination - one step at a time.

    Bob - Palmyra NY
    2 - 69 CB750, 1 Turbo
    1 - 71 CB750

  3. #3
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92
    compression crossed my mind, but i just rebuild the cylinders with a hone and new rings. I'll do a test as a process of elimination.

    Do you do compression tests on a warm or cold engine??

  4. Remove Advertisements
    CafeRacer.net
    Advertisements
     

  5. #4
    Senior Member kenessex's Avatar
    Join Date
    Oct 2005
    Location
    Galena, AK, USA.
    Posts
    5,780
    First thing you need to do is establish a baseline. Take the time to do it right instead of just using the shotgun approach and hoping that you hit it. Set your timing, even if you just did it, check it again. Replace your plugs, even if they look OK, change them. Adjust your valves, even if you just set them, check them again, they may have loosened or tightened up if you just did the top end. Check all your electrical connectors from the ignition switch and kill switches, points and coil wires. When you have all this done, then you can start looking for specific issues such as coils or compression. Otherwise you can end up chasing a non existent problem like compression that is actually a tight valve.

    Good luck, but diagnosis is a very reasoned methodical endeavor that easily goes astray.

    Ken
    WERA 119
    CCS 119
    CRA 119
    AHRMA not anymore
    \"Think twice before you speak, and then you may be able to say something more insulting than if you spoke right out at once.\"
    Evan Esar
    Newbies, Geeto and Tex (Bye Tex)hate me!!

  6. #5
    Senior Member bmartin's Avatar
    Join Date
    Feb 2008
    Location
    Palmyra, NY, USA.
    Posts
    2,740
    You can check your compression with a cold engine. As the notes above indicate, have a plan to check out your engine in a system type fashion. In my option, start with compression, check your valves settings, Plugs (don't forget to read them and check for fire on the plugs, move to the fuel section and then your ignition and electrical connections. Each of these checks is quick to do and may also indicate more clues on your real problem. The main objective is to leave nothing out and have a systematic method for checking the major components to help determine your problem. Leaving out something (just because it's brand new) really opens you up to missing the real problem...
    Bob - Palmyra NY
    2 - 69 CB750, 1 Turbo
    1 - 71 CB750

  7. #6
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92
    sounds good, i'll do a simple tune up on her to make sure the basics are in smooth working order.

  8. #7
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92
    quote:Originally posted by cb175guy

    sounds good, i'll do a simple tune up on her to make sure the basics are in smooth working order.
    Valves are good
    Ignition is perfect (light goes on right at the "f" mark)
    condenser is new
    point looks strong
    plugs worked, but put new ones in,
    ignition has spark
    Carbs are clean, good flow to each carb.

    I can't for the life of me find the adapter for my compression gauge. I might have lent it to a friend, and it never returned....grrrrr
    I'll post up my compression readings once I get them....
    I am assuming there will be a slight difference in readings since i will be testing compression on a cold engine.

  9. #8
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92
    So i could not retrieve the adapter for my compression gauge so I made on out of a rubber stopper. Compression was at 100 on each side.....

    not good.

    Just does not make sense. The bike has 5K miles on it and I honed the cylinder and put new rings in. That should have done the trick. Any other suggestions how I would loose compression.

    This was done on a cold motor

  10. #9
    Senior Member bmartin's Avatar
    Join Date
    Feb 2008
    Location
    Palmyra, NY, USA.
    Posts
    2,740
    Try adding a tea spoon of oil to each cylinder and re-try the compression test. If the compression goes up, then your piston rings are more than likely either not seated yet or the rings were not positioned correctly when installed. (The split of the rings should have been positioned 180 degrees from each other.) If there is no change in compression (with the oil added) - then your valve seats are more than likely your issue. I would say your compression should be up around 125 to 150. Based on what you have been saying here - it's looking like your valves need a little TLC.

    I am having a similar issue with one of my cb's - I'm thinking my #2 exhaust valve is sticking open. My compression test of that cylinder is down around 95 (the other cylinders were all up around 125). When the engine gets up to operating temp, I'm hearing popping thru the exhaust and noise from that cylinder at idle... My fix will be to replace the engine with one a rebuilt one off my work bench that's ready to go and rebuild that one that's in the bike.

    Your fix might be to pulling the head and having the valves rebuilt and or checking your cylinders and rings.
    Bob - Palmyra NY
    2 - 69 CB750, 1 Turbo
    1 - 71 CB750

  11. #10
    cb175guy's Avatar
    Join Date
    Jan 2008
    Posts
    92
    great advice, thanks. I'll try that this weekend, but right now....

    It's beer thirty, and my GF is looking might fine in my sweatpants....

Page 1 of 2 12 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
  •  

Similar Threads

  1. Electrical
    By Danny Yourd in forum Technical
    Replies: 3
    Last Post: 08-31-2011, 09:17 AM
  2. late 69 cb175 and 70 cb175 for sale
    By jringo in forum Bikes For Sale
    Replies: 0
    Last Post: 06-14-2011, 12:33 AM
  3. Replies: 2
    Last Post: 05-18-2011, 12:24 PM
  4. possible electrical problem? I"M STUMPED!
    By motogonzo in forum Technical
    Replies: 5
    Last Post: 02-28-2011, 11:41 AM
  5. cb175 carb problem
    By vw505 in forum Technical
    Replies: 0
    Last Post: 02-16-2009, 06:30 PM

Search tags for this page

cb175 bad coil

,

cb175 electrical issues

,

cb175 electrical problem

,

cylinder fin rubbers cb175

Click on a term to search for related topics.