Project MC19 '89 250r

Discussion in 'Your 250cc Projects' started by an_anonymous_user, Dec 5, 2020.

  1. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    so tomorrow im finally to take delivery of my very own 250 and im thinking about what i should do with it for a project im thinking i want to get it as close to a rr model as i can. but i want some help with how i would carry that out is there a way to fit dual discs on the front and is it even worth unlocking that extra 1000rpm?
    thanks in advance
     
  2. jmw76

    jmw76 Well-Known Member

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    Hi Anonymous.

    Welcome to the forum.

    If it was my bike, I would probably build the bike as close to standard as possible. At least from a looks point of view anyway.
    The MC19 is really seen as the start of the 250R & RR family.
    I believe that the MC19 (with their twin headlights will be sought after in years to come).

    It is a personal preference thing as to whether you like the looks of the MC22 over the 19.
    I have a couple of MC22s (an early 250RR and a later 250RRR). The later bike has the restricted engine and is limited in revs (18k) and power (40bhp). I also have my little RC replica which is built around the MC19 engine.
    To be honest, they all feel much the same from a performance point of view. The MC19, technically should be similar in performance to my early 22. I really can not pick a big difference moving between them all.
    I have heard that the MC19 has the hottest cam profile of all the MC14E based engines.

    The twin disks look good (in my opinion) but the single disk is every bit as good in stopping power and is lighter (a preference from a racing perspective). To get the twin disk look, you will have to change fork tubes, wheel, speedo drive mechanism (MC22 speedo is driven from the engine primary sprocket. Not sure if it will just bolt up to the MC19 engine) and possibly triple clamps (spacing is slightly different between MC19 & 22). In my opinion, a waste of time. The same with changing the rear swing arm to the MC22 style and then all the little subtle differences to the plastic.

    If you really like the MC22 look, go and buy one.

    Just concentrate on making your MC19 as good as you can and enjoy riding it.

    There are some really nice MC19s out there and they look every bit as good as the MC22s.


    Peter.
     
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  3. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    thank you for your response
    ok well then to that end any modifications performance wise or even cosmetics/comfort that anyone would suggest

    also the bike has an electrical issue wherein it is apparently doing immense damage to the battery upon starting any ideas? for context it is an unfinished project bike upon buying and pieces of the wiring harness has been cut for project reasons any areas that i should be looking at?
     
  4. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Agree with Peter 100%. The 19 is special just as it is.
     
  5. Murdo

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

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    It is your bike to decide, but my opinion would be to do a stock restore (as it will be worth more in time to come) and get it running as per the factory specs.
    Replacing the TCI with an aftermarket one 'may' give a little more mid range to the power but you run the risk of engine damage as they have no rev limiter.
    A good service checking compression, setting the valves, clean and balance carbs, etc will make for a reliable and fun bike to ride.
     
  6. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    Anonymous, what does "...wherein it is apparently doing immense damage to the battery upon starting..." actually mean?

    Is the battery overcharging? If so, this is normally a sign that your Regulator/Rectifier has stopped working properly. We need a bit more detail before offering suggestions on what the issue(s) could be.
     
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  7. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    thanks ill put checking that on my to do list
     
  8. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    one question where is the regulator on the bike, anyone know because im worried i do not currently have one
     
  9. Gen

    Gen Well-Known Member

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    Follow the wires from the alternator, until you see a plug, then follow those wires,,and search the net for a wiring diagram,
     
  10. jmw76

    jmw76 Well-Known Member

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    The reg/rectifier on the MC22 is fixed to the rear subframe. I think it is the same on the MC19.
    Remove the side plastics (around/behind the seat) and you should be able to find it.
     
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  11. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    yeah finally found the rectifier hiding in plain sight and found it mounted incorrectly and considering the hot and high humidity climate i think i have good reason to believe that its dead so i think ill have to get a new one do i go to my honda dealer and get a honda genuine rectifier or is it worth the effort of getting something like an sh775?
     
  12. kiffsta

    kiffsta Senior Member

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    you cant really tell if it is dead by looking at it, unless the its cracked and has bits hanging out.

    Grab a multmeter ,
    check your battery voltage without the bike running - this is called Battery at rest - you should see around 12.4v
    Start your bike and check voltage - you should see 12.7-12.9v
    Revs your bike to 5000 rpm and check the voltage - you should see 13.9 - 14.2v

    If you are not seeing those sorts of figures, unplug your voltage reg and switch your meter to AC volts and measure the voltage on the 3 yellow wires with your bike at 5000rpm, you see 45v AC per each yellow wire (per phase)

    Finally check the plug and wires going to your reg, they get hot and can become crispy reducing their effectiveness, if they are munted, this is a cheap fix

    Honda CBR250RR Regulator connector CNT01 (xcitebikes.com.au)
     
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  13. jmw76

    jmw76 Well-Known Member

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    There are a number of reg/rect devices on ebay for very reasonable prices. I can not guarantee quality. Just do a search.
     
  14. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Re the sh775, iF the bike is a keeper then I would recommend the better quality item.
     
  15. jmw76

    jmw76 Well-Known Member

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  16. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    You can pick up 2nd hand Shindengen FH020AA regulators for not very much, most modern Japanese & Euro models use them, and the wiring is easy once you have the plugs. 3x stator wires in, positive and earth to the battery. Mount it somewhere with good airflow. Job done.
     
  17. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    thanks for all the help so far, another lot of electrical questions because such problems are just so much fun. right now its the ignition coils. where does the wiring for the come from, where do they mount (if they mount) and what wires am i looking for
     
  18. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    recently started working on my 1988 cbr250r again. tried starting it with what i thought was a dead starter motor, and for a split second it sounded perfectly fine. tried starting it again with a fully charged battery, and after a few attempts it seemed to make an attempted start at full health, after these few attempts i checked the battery, the terminals, terminal wires and battery were hot, as well as the wiring for the starter motor.

    i was hoping to get some advice for what is wrong with the starter itself (if there is even anything wrong with it) and the wiring
    thanks in advance
     
  19. Murdo

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

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    Check ALL terminals for corrosion or loose wires from Battery to starter motor. Also the wire from battery negative to engine to frame.
     
  20. an_anonymous_user

    an_anonymous_user Active Member Premium Member

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    i can already confirm corrosion on the negative terminal hook-up, i believe if memory serves there is corrosion on the positive hook-up as well, ill have to go and check for corrosion elsewhere.
    what can i do to repair corrosive damage to these components?
     
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