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CBR600FX 1998 regulator/rectifier issue or battery?

Discussion in 'Biker's Cafe' started by helpimcrap, Sep 21, 2018.

  1. helpimcrap

    Capodecina

    Joined: Jan 13, 2004

    Posts: 12,401

    Location: Leicestershire

    Hi all,
    I know it's the CBR curse, but just double-checking.
    Bike started ok, went for a ride, struggled to restart. Battery had gone flat after lack of use but recharged. I run with lights on all the time.
    Battery was showing about 12v with engine off and 12.5v idling, struggling to restart.
    After a couple of days I went to restart and it turned over fine.
    Any recommendations other than replacing the regulator rectifier with a Honda part?
    I've seen ones with heatsink fins on?
    Are these better?
    Also seen people replace with R6 ones and rewire?
     
  2. bloodiedathame

    Sgarrista

    Joined: May 11, 2007

    Posts: 7,722

    Location: Surrey

    I replaced my Triumph reg/rec with a compufire one imported from the states, a much better design (not shunt). https://compufire.com/
     
  3. skyripper

    Wise Guy

    Joined: Jul 19, 2011

    Posts: 2,070

    If you end up replacing the Regulator/Rectifier, look at the Electrexworld website, as they are the OEM for many bike manufacturers.
    Typically a lot cheaper than the "official" part in a different cardboard box.
     
  4. Freeman

    Soldato

    Joined: Jul 24, 2004

    Posts: 5,564

    How old is the battery?
    Did you put the battery on a charger before going out for a ride?
    12v is very low, it means it's only about 50% charged.
    12.5 is near enough fully charged but not quite so I wouldn't solely blame the rectifier yet.

    Stick it on a charger for a bit, ride the bike more longer and more regularly and then check it again.

    If it's still losing charging or struggling to start, then think about looking into changing the rectifier.
     
  5. Munchies

    Gangster

    Joined: Oct 4, 2010

    Posts: 130

    My VFR battery died last weekend, after replacing the clutch I had no electrics but 12.5v across the battery when off.
    With ignition on the voltage dropped to 5v, so I searched high and low for an issue in the wiring, there wasn't one. Then noticed the battery was getting HOT on the neg side. Replaced it, all's good.

    What is your voltage with ignition on, but engine off?

    When checking the voltage with motor running, check at 3 - 5k revs, as generally you get more R/R output there than idle.

    It's worth removing the R/R plug and checking to see if it's burned at all, and if not check the R/R with a multimeter.
     
  6. helpimcrap

    Capodecina

    Joined: Jan 13, 2004

    Posts: 12,401

    Location: Leicestershire

    Battery I imagine is a few years old. I've had the bike nearly 2 years.

    Checked it just now not turned on - 11.8v on DCV (Direct Current Volts?).

    Started like it was fully charged. When running on choke 14.5v across terminals although dipped to 13.5v on occasion.

    Think there's a dead cell in the battery? It's on charge now anyway.
     
  7. Munchies

    Gangster

    Joined: Oct 4, 2010

    Posts: 130

    Charging sounds ok, so either battery, or parasitic draw.

    If it's not in regular use the battery could be dying, but charge it, and see if it holds its charge.
     
  8. helpimcrap

    Capodecina

    Joined: Jan 13, 2004

    Posts: 12,401

    Location: Leicestershire

    Definitely battery I'm thinking now. Took it for 10mile run with lights on to friends, he tested it at 12.0v off and at 4krpm 13.5v.
    Got home with lights on, turned it off. Wouldn't even turn over once! Flat as a pancake.

    Went out 20mins later to put on charge... Thought I'd try it again... Started 1st time strong as an ox! I'm thinking battery was overheating?
    Rectifier felt only a bit warm after the 10mile run. Brought battery inside to charge, and read fully charged after 10mins of reading fully discharged.

    I love diagnosing electrics lol.
     
  9. Munchies

    Gangster

    Joined: Oct 4, 2010

    Posts: 130

    Definitely sounds like battery to me. If you're loathed to spend money a new one without 100% certainty, 'borrow' your mates, when he's not looking, and see if it fixes the issue :D
     
  10. helpimcrap

    Capodecina

    Joined: Jan 13, 2004

    Posts: 12,401

    Location: Leicestershire

    Bought one on eBay from Tayna Batteries for £25 delivered. I bought one for my Porsche from them. I had a refund last week on something I returned back a while ago so less than £20. :Cool:

    Half the price for one delivered next day than from local places like dealers or Halfords etc.
     
  11. MowyTone

    Mobster

    Joined: May 4, 2009

    Posts: 3,366

    Location: Southampton

    Always replace battery if in doubt. Much easier than faffing with the rest of it to begin with
     
  12. BUDFORCE

    Wise Guy

    Joined: May 3, 2012

    Posts: 2,038

    Yea true, plus if the bike is a few years old (plus battery potentially older) even if it ain't the battery it's probably good to change it out anyway, it's not wasted money.