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

Help Restricted FZR250

Discussion in 'Yamaha 250cc In-Line 4's' started by Willrcr15, Oct 4, 2019.

  1. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    What's done to de restrict it ? I've a fresh re built FZR 3LN & she does a lap & comes back in saying it won't go & little else feedback other than maybe it was seizing but it's not that, then it dawned on me it'll be restricted. I have other ECU's I can try but is it more than that or maybe it's just cut a wire that reads the ignition pulse of the RPM. Thought I read somewhere there was a link in the speedo related to a restriction. Busting to get her going & see what a fresh engine pulls like, we currently run another one that goes so well.
     
  2. kiffsta

    kiffsta Senior Member

    Messages:
    9,066
    Likes Received:
    6,872
    Trophy Points:
    1,168
    Joined:
    Aug 7, 2010
    Gender:
    Male
    Location:
    Brisbane
    What year is yours ? Jap law changed in 1994 which restricted the power output to 40hp, Honda changed the cylinder head and cdi to reduce their power output, Kawasaki changes were in the cdi. Most restrictions were in the speed limiter so that you couldn’t go over 180kms per hour
     
  3. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

    Messages:
    4,313
    Likes Received:
    2,383
    Trophy Points:
    898
    Joined:
    Jun 18, 2016
    Gender:
    Male
    Occupation:
    Panel Beater, Spray Painter, Custom Fabricator
    Location:
    Adelaide, South Australia
    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    The only restrictions besides the 180km/h speed restrictor in an FZR250 is the valve spring's and cams.
    You probably have carby issues
     
    • Like Like x 1
  4. Amara

    Amara Active Member

    Messages:
    98
    Likes Received:
    21
    Trophy Points:
    178
    Joined:
    Apr 25, 2019
    Location:
    Australia
    My Bike:
    1989 Yamaha FZR 250R 3LN1
    Make sure that you have the right CDI box for your bike. You could have one for the later lower revving version of the 3ln engine like the one in the Zeal
     
    • Like Like x 1
  5. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    Thanks all, i'll check the box, now i'm wondering if the exhaust valve isn't opening. Carbies are perfect but anythings possible,
     
  6. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

    Messages:
    4,313
    Likes Received:
    2,383
    Trophy Points:
    898
    Joined:
    Jun 18, 2016
    Gender:
    Male
    Occupation:
    Panel Beater, Spray Painter, Custom Fabricator
    Location:
    Adelaide, South Australia
    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
  7. Willrcr15

    Willrcr15 Well-Known Member

    Messages:
    549
    Likes Received:
    399
    Trophy Points:
    373
    Joined:
    Nov 11, 2013
    Gender:
    Male
    Location:
    Newcastle
    My Bike:
    FZR250 3LN 89
    That's a good link, i'm sure it's not that, also it's a 240 speedo.
    Carbies are perfect & better than new, i have 3 sets, tried em all.
    The more I think about it the more i'm thinking the exhaust valve, already had it apart but maybe a cable snapped or the servo's playing up or something sent to test me again. Be bloody beautiful if they just started making them again, i'd buy a new one tomorrow !
     
    • Like Like x 1
  8. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,730
    Likes Received:
    2,870
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    EXUP should be easy to diagnose, it cycles with the ignition, pull the left rear fairing off and watch the servo motor to see if it's working... should be able to pinch the free play out of the cables on both ends... check the exhaust side too.

    Disconnect the cables and manually operate the exhaust valve. It can also be removed for service and cleaning.
     
  9. Amara

    Amara Active Member

    Messages:
    98
    Likes Received:
    21
    Trophy Points:
    178
    Joined:
    Apr 25, 2019
    Location:
    Australia
    My Bike:
    1989 Yamaha FZR 250R 3LN1
    Doesn't the rev gauge double as a fault code reader ? e.g. 7,000rpm = bad fuel pump ? Or am I thinking of a different bike ?
     
  10. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,730
    Likes Received:
    2,870
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    Not on these... early fuel injected bikes, yes.
     
  11. Laceysnr

    Laceysnr Active Member

    Messages:
    82
    Likes Received:
    34
    Trophy Points:
    188
    Joined:
    Jul 22, 2019
    Gender:
    Male
    Occupation:
    Hacker
    Location:
    Exeter, UK
    Home Page:
    My Bike:
    '98 Suzuki Across + '16 Sprint GT 1050
    Related: I was wondering just yesterday how the Across was restricted? It's a lower power output AFAIK, not a speed limit, but haven't seen anything around the intake during my work on the bike. Anybody know?
     
  12. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,730
    Likes Received:
    2,870
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    The across is a heavier bike and only has two twin-throated carbs. More touring oriented. All grey import jap bikes of this era will have a 180km/h speedo restrictor circuit. Later 40hp bikes are generally built to that power via heads and cams, sometimes ignition timing and carb jets.

    Really the 250's are built to 45hp and 40hp, to get more out of them you have to spend big and do a lot of work, then you start blowing clutches and transmissions without modifications... focus on finding and fixing the problem.

    If the EXUP is stuck or not fully open, that will be a problem at full tilt.

    If it has no power I would start with checking that it is getting adequate fuel... a blocked breather on the tank can do this, as can a blocked filter, or a kinked fuel line... work your way down the system you are diagnosing.

    The only real common issue on the FZR's is the emulsion tubes and needles wearing badly. They will run pig rich, bog, and consume 5L V8 amounts of fuel. Turning the fuel off temporarily can help to diagnose this. Generally with this problem they are OK at high revs and terrible everywhere else.
     
    • Like Like x 2
    • Agree Agree x 2
    Last edited: Oct 8, 2019
  13. Laceysnr

    Laceysnr Active Member

    Messages:
    82
    Likes Received:
    34
    Trophy Points:
    188
    Joined:
    Jul 22, 2019
    Gender:
    Male
    Occupation:
    Hacker
    Location:
    Exeter, UK
    Home Page:
    My Bike:
    '98 Suzuki Across + '16 Sprint GT 1050
    Yeah I don't need more out of the Across, was just curious if it was easy to get the restricted later models back up to 45.
     
  14. Amara

    Amara Active Member

    Messages:
    98
    Likes Received:
    21
    Trophy Points:
    178
    Joined:
    Apr 25, 2019
    Location:
    Australia
    My Bike:
    1989 Yamaha FZR 250R 3LN1
    Fairly sure this is for the FZR
     

    Attached Files:

  15. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

    Messages:
    4,730
    Likes Received:
    2,870
    Trophy Points:
    943
    Joined:
    Mar 18, 2014
    Location:
    Sydney NSW
    My Bike:
    FZR250R 3LN6
    FZR250's don't have a TPS, speed sensor (gearbox driven speedo) or tip over sensor.

    Those codes apply to some early fuel injected Yamahas, and some late carb Yamahas like my R6, which has a TPS on the carbs, a gearbox driven speedo, but no EXUP. Has a 4-2-1 exhaust instead.

    Each manufacturer will have a different built in diagnostic.

    Modern bikes are all OBD2 standard and can be read with a code reader and the right cable.

    It's not common for carbed bikes to have anything like that, generally the only electrics they have are ignition system and lights/instruments.
     
    • Like Like x 1
    • Agree Agree x 1
  16. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,225
    Likes Received:
    1,416
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    Keyster kits through the carbs?

    If so stay tuned whilst I find the relevant posts for you - I think I know what the problem may be
     
  17. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,225
    Likes Received:
    1,416
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    First post located

    https://www.2fiftycc.com/index.php?threads/the-second-fizzer.9044/page-15#post-108129

    @my67xr - original discovery
    https://www.2fiftycc.com/index.php?threads/fzr250r-3ln3-bdst28-carburetors.9643/#post-105292

    Second thread - note; if at some stage because you have several sets of carbs, different components - emulsion tubes N625 VS N638 etc need the corresponding air jets, main jets differ and so on - all 5CT7 needles with shims below centre carb pair of or a combination of 5CT7 - outer pair and 5CT9 - inner pair all on the same clip setting and no shims underneath any of the needles

    https://www.2fiftycc.com/index.php?...ne-behind-block-head.10478/page-4#post-123212

    This thread covers the differences in the needle(s) - it's a PITA, but as @my67xr & @Joker discovered - minute differences/errors produce big consequences where the carbs are concerned

    https://www.2fiftycc.com/index.php?...8-26mm-carb-settings-specs-3ln-3yx-zeal.9787/

    How much do we all love Fizzer carbs - let's have a show of hands shall we...
     
  18. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,914
    Likes Received:
    6,709
    Trophy Points:
    1,168
    Joined:
    Jun 14, 2012
    Gender:
    Male
    Occupation:
    Between a Rock and a Hard Place
    Location:
    North by NW NSW Oztralia - Tamworth
    My Bike:
    *Kawasaki ZXR250C *Yamaha FZR250R 3LN1 *Yamaha FZR400 *Triumph Bonneville 750 T140V *Triumph Daytona 675 *Triumph Tiger 800XC
    :D

    middle-finger-middle-finger-hand-png.png
     
    • Funny Funny x 2
    • Like Like x 1
  19. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    3,225
    Likes Received:
    1,416
    Trophy Points:
    918
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    OOH Lah dee dah - Mr Fuel injection is showing off now - which makes me wish that if microsquirt units were a little cheaper I'd have a go at fuel injecting a fizzer, but alas they're not so I won't
     
    • Like Like x 1
    • Funny Funny x 1
  20. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

    Messages:
    1,060
    Likes Received:
    514
    Trophy Points:
    543
    Joined:
    Feb 19, 2014
    Gender:
    Male
    Location:
    Tamworth NSW
    My Bike:
    Yamaha FZR 250 3LN3, Triumph Sprint ST 955i
    Yeah, we love Fizzer carbs!!!

    fzrcarb01.JPG

    Got the LiteTek kit ready :thumb_ups:

    LitekFZR1.JPG
     
    • Like Like x 2
    Last edited by a moderator: Oct 11, 2019

Share This Page