/ Register

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Help Question to all Honda CBF250 owners - Ignition coils specs question.

Discussion in 'Honda 250cc Singles' started by hogclassics, Jul 1, 2022.

  1. hogclassics

    hogclassics Active Member Premium Member

    Messages:
    31
    Likes Received:
    11
    Trophy Points:
    78
    Joined:
    Jun 30, 2022
    Gender:
    Male
    Occupation:
    Wildlife Artist & motorcycle restorer
    Location:
    United Kingdom
    My Bike:
    Honda Super Magna (x2) , V30, Goldwing (x2) CBF250 2008
    Hi CBF250 owners.

    Does anyone technical know what the ignition coil primary & secondary resistances are
    please for the CBF250 as the only manual doesn’t give us any idea of specs?

    The barn find CBF250 2008 I bought only shows a primary resistance of 0.5 ohms and secondary
    resistance of 13,500.

    The spark test shows a very tiny orange spark, which is a weak ignition system.
    The reason the bike won’t fire up.

    In the UK finding a compatable coil for the CBF250 is virtually impossible.
    Has any CBF250 owner exchanged their coil with success for another type, if so
    what works?
    Fitting the wrong coil could ruin the also rare CDI.

    Any advice is greatly appreciated riders & wrenchers.

    Many thanks

    Hog
     
    hogclassics, Jul 1, 2022
    #1
  2. trevorlatala

    trevorlatala Active Member Contributing Member

    Messages:
    81
    Likes Received:
    59
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer now retired
    Location:
    Staffordshire United Kingdom
    My Bike:
    Honda CB250 rs Jawa 350 TS
    Is the alternator hv winding generating the high voltage required to charge the CDI unit These windings can go open circuit
    you should take out the plug ( to make life easier connect an ac voltmeter to the CDI hv input and then kick/ crank it up see if you get the voltage The ignition coil for a CDI unit normally has a very low primary resistance
    Trev
     
    • Informative Informative x 1
    trevorlatala, Jul 1, 2022
    #2
  3. hogclassics

    hogclassics Active Member Premium Member

    Messages:
    31
    Likes Received:
    11
    Trophy Points:
    78
    Joined:
    Jun 30, 2022
    Gender:
    Male
    Occupation:
    Wildlife Artist & motorcycle restorer
    Location:
    United Kingdom
    My Bike:
    Honda Super Magna (x2) , V30, Goldwing (x2) CBF250 2008
    Hi Trev!

    Thanks for your reply buddy.

    The bike cranks with gusto but doesn’t fire up.
    I can’t test the alternator as it won’t run mate!

    I bought the little bike for my lassie and she’s really disappointed that someone sold us a defective bike.

    Best

    Gog
     
    hogclassics, Jul 1, 2022
    #3
  4. hogclassics

    hogclassics Active Member Premium Member

    Messages:
    31
    Likes Received:
    11
    Trophy Points:
    78
    Joined:
    Jun 30, 2022
    Gender:
    Male
    Occupation:
    Wildlife Artist & motorcycle restorer
    Location:
    United Kingdom
    My Bike:
    Honda Super Magna (x2) , V30, Goldwing (x2) CBF250 2008
    Ooops sorry busy day.
    Should be Hog! Sorry y’all!
     
    • Like Like x 1
    hogclassics, Jul 1, 2022
    #4
  5. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,108
    Likes Received:
    3,477
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    As ignition coils are a very simple part, it is extremely rare for them to be faulty. On the other hand, you can expect the TCI unit to be your problem.
     
    maelstrom, Jul 1, 2022
    #5
  6. trevorlatala

    trevorlatala Active Member Contributing Member

    Messages:
    81
    Likes Received:
    59
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer now retired
    Location:
    Staffordshire United Kingdom
    My Bike:
    Honda CB250 rs Jawa 350 TS
    the engine does not need to run !Do you have a multie meter ? you need to connect to the high voltage coil that goes to the CDI unit then set the meter to ac volts ! Crank the bike up and the meter should indicate a voltage
    If it does the Cd1 is possibly faulty if not you may have a faulty hv winding I mention this as I had the same thing on my Honda
    Trev
     
    • Like Like x 1
    trevorlatala, Jul 1, 2022
    #6
  7. hogclassics

    hogclassics Active Member Premium Member

    Messages:
    31
    Likes Received:
    11
    Trophy Points:
    78
    Joined:
    Jun 30, 2022
    Gender:
    Male
    Occupation:
    Wildlife Artist & motorcycle restorer
    Location:
    United Kingdom
    My Bike:
    Honda Super Magna (x2) , V30, Goldwing (x2) CBF250 2008
    Thanks for your advice buddy.

    How do you thorough tests on these cdi’s please? One came with the bike and the other was an Ebay purchase ‘off a running bike!’ it maybe be true.

    Many thanks

    Hog
     
    hogclassics, Jul 2, 2022
    #7
  8. hogclassics

    hogclassics Active Member Premium Member

    Messages:
    31
    Likes Received:
    11
    Trophy Points:
    78
    Joined:
    Jun 30, 2022
    Gender:
    Male
    Occupation:
    Wildlife Artist & motorcycle restorer
    Location:
    United Kingdom
    My Bike:
    Honda Super Magna (x2) , V30, Goldwing (x2) CBF250 2008
    Hi Trev

    Thanks for your advice buddy.

    To do a leakdown test the bike needs to run. This is what another member advised.

    I will certainly try this.
    I also bought a genuine Honda coil and it didn’t do very much.

    Another member advised the ignitor circuit on the stator could be the none spark problem. If the ignitor circuit doesn’t boost the spark, then it will
    never fire up!

    In the UK a new Honda stator would cost £260 Brit Pounds.
    Has any CBF250 owner bought a cheaper new pattened one off Ebay?

    Thank you everyone for brain storming this good cranking, but not firing CBF250.

    Best

    Hog
     
    hogclassics, Jul 2, 2022
    #8
  9. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

    Messages:
    6,400
    Likes Received:
    4,788
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    You do not have to have the engine running to do a leak test. Put a fitting in the plug hole, add 30psi from air line and listen at carb, exhaust and gearbox filler hole to hear where air is going.
     
    Murdo, Jul 2, 2022
    #9

Share This Page