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

Help CBR250rr project - pilot screw setting

Discussion in 'Honda 250cc In-line 4's' started by Mar7inez13, Nov 24, 2016.

  1. Mar7inez13

    Mar7inez13 Member Premium Member

    Messages:
    31
    Likes Received:
    7
    Trophy Points:
    18
    Joined:
    Jul 3, 2016
    Gender:
    Male
    Location:
    North Lakes
    My Bike:
    Honda CBR250RR
    Hey peps
    Been a while had to put project on hold for a while...
    Anyway I have just rebuilt my carbys
    Off a mc22 but thenew heart i put in a while ago is a mc19...
    So with the pilot and idle setting what do I set them at???

    mc 22 specs or mc 19 specs

    Cheers
     
  2. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    5,102
    Likes Received:
    3,472
    Trophy Points:
    1,148
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
  3. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    Start with stock settings for your engine specs (MC19) then do as Maelstrom suggests would be my plan of attack.
     
  4. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    On pretty much 99% of everything Maelstrom says I agree with but for some reason in my experience the mc22 pilot screws don't play ball like they are meant to with the whole tuning by ear thing.
    If its mc22 carbs and an mc19 engine I am going to take a guess and presume that the carbs are the post 1993 model as the intake ports on both the later mc22 and the mc19 are smaller than the 1990-1992 L/N variant making them a compatible fit.
    I imagine L/N model carbs wouldn't fit right as they are designed with bigger intake ports.
    The way the mc19 seems to compensate for this (in my opinion/guess) is with the longer duration on the lift time on the cams.
    So with all that being said and I may be connecting dot's that aren't there but since the mc19 pulled the same PS as the L/N model I would actually wager that 1 and 3/4 with 105 main jets is going to be the best bench mark setting based on the fact that they are mc22 carbs. That's just my shonky opinion, take from it what you will.
     
  5. Mar7inez13

    Mar7inez13 Member Premium Member

    Messages:
    31
    Likes Received:
    7
    Trophy Points:
    18
    Joined:
    Jul 3, 2016
    Gender:
    Male
    Location:
    North Lakes
    My Bike:
    Honda CBR250RR
    Thanks right on it as usual...
    Umm the carbs are off an L series mc22
    And the engine number starts with a 4 so I am only guessing that it is what i said about...
     
  6. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    If it fits it fits I guess, not sure if the internal diameter of the carbs throats is a different size or not but if the diameter is the same is the R version I still say just set them the L models specifications of 1 3/4, you wont notice an insane difference going 1 quarter either way of that. There is no harm trying to do it by ear, I just find that the revs keep increasing until your almost 3 turns out on all 4 which cant be right so, thats whats happened to me anyway.
     
  7. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,914
    Likes Received:
    6,708
    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
    • Like Like x 1
  8. Mar7inez13

    Mar7inez13 Member Premium Member

    Messages:
    31
    Likes Received:
    7
    Trophy Points:
    18
    Joined:
    Jul 3, 2016
    Gender:
    Male
    Location:
    North Lakes
    My Bike:
    Honda CBR250RR
    Hey!?
    I was wondering... are all four barrels meant to open at the same time or does it open 2,3,1,4??
    I think I need to sync the carbys before I play with it to much more
     
  9. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    For lack of better words its based on the amount of flow going to each cylinder, you want it to be equal.
    Bench syncing so they are all the same is a good starting point however when I plugged the morgan carb tune in after the flow was not even among the cylinders. Syncing to a carb synchronizer ended up giving me better results than just making all 4 the same with a guitar string.
     
    • Like Like x 1
  10. Mar7inez13

    Mar7inez13 Member Premium Member

    Messages:
    31
    Likes Received:
    7
    Trophy Points:
    18
    Joined:
    Jul 3, 2016
    Gender:
    Male
    Location:
    North Lakes
    My Bike:
    Honda CBR250RR
    I thought that was the case well ill start there if i have any questions i stir you up
    Thanks again guy
    Im hang to ride this beast
     
  11. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    I just read that 3 times and I am still confused... I can't correlate how you got to 1 3/4 turns with 105 main jets from anything you said there... ?
     
    • Like Like x 1
  12. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    It's just what I would try, more gut instinct than a scientific explanation. I have probably played around with mc22 carbs for more hours than most. But to just bluntly summarize my non nonsensical ramble I was trying to say "its the same engine with the same power, odds are the volume of air going through it will be similar and the velocity the air travels during the atomization in the carbs will be more relevant to mc22 because nothing to do with the mc19 has come into play yet.
    Wrong or idiotic its actually allot faster to just try then mathematically work out such a thing with so many variables.
     
  13. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,914
    Likes Received:
    6,708
    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
    Happens to me every day on this forum :idk:
     
    • Like Like x 3
  14. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    https://en.oxforddictionaries.com/definition/internet_forum
    A facility on a computer network (now usually the Internet) for users to share information or opinions on a particular topic, especially a website dedicated to such discussion.

    I shared info and opinion, if it doesn't make sense I urge you to help this poor new person with a more rational response, having a forum to point people to a manual is nothing short of telling someone to buy a watch when they ask for the time.
     
    • Like Like x 1
  15. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,914
    Likes Received:
    6,708
    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
    My comment wasnt in reference to anyone in particular ..... just my general impression of half the posts I read daily

    Alot of the posts/threads are edited by me because of poor grammer, spelling, auto correct/fill on phones , lack of comprehension, spacing or making sense of something because they havn't checked before they posted..... etc etc etc

    And then theres posts that just totally baffle me ..... but then thats entertainment for me.

    I point people to a manual because they are surely able to read ..... its how I learnt alot of what I know ..... and many many times Ill find the appropriate page or diagram and post it up for them.

    I dont use a watch .... I look on my phone , clock radio , microwave , computer or car dash :cool:

    rant completed

    Heres a day in the life ....

    log.jpg
     
    • Like Like x 3
  16. Damus

    Damus She is a BEAST and riding it is comparable to sex Dirty Wheel Club

    Messages:
    1,055
    Likes Received:
    426
    Trophy Points:
    493
    Joined:
    Mar 22, 2015
    Gender:
    Male
    Occupation:
    I.T.
    Location:
    Sydney, NSW
    My Bike:
    Honda CBR250RR
    Sorry, I know my paragraphs looks like someone threw a brick in a washing machine. The hard work you put in is appreciated.
     
    • Like Like x 2
  17. sharky

    sharky Well-Known Member

    Messages:
    482
    Likes Received:
    325
    Trophy Points:
    273
    Joined:
    Aug 5, 2016
    Gender:
    Male
    Occupation:
    daredevil
    Location:
    Tweed heads
    My Bike:
    kawasaki zxr 250c
    To tweak the carbs individually by ear try increasing rpm to 2000,should be easier to find the sweet spots.
     
    • Like Like x 1
  18. Joker

    Joker See "about me" for contact details. Contributing Member

    Messages:
    2,737
    Likes Received:
    1,399
    Trophy Points:
    798
    Joined:
    Feb 2, 2014
    Gender:
    Male
    Location:
    Switzerland
    My Bike:
    SV1000SK3
    I think it’s true that there probably isn’t a manual for retrofitting carburettors to a different bike, so I think opinions and such are all welcome in that regard. At the same time it’s probably worth considering keeping it simple, even as an engineer I can’t give you advice on how to gather, interpret and implement the complex mathematical & engineering data and modelling required on fluid flows/atomisation/velocities etc without doing quite a substantial amount of background work (plus there’s no way I would remember it so I’d have to re-learn it and find the software to model it properly – not something I would ever bother with). So I think the advice of starting at the benchmark for the carby setting and tuning it by ear is very good advice.

    I think Grey is highlighting that there is a lot of people out there who prefer to ask the questions then read the manual/use google/learn for themselves and for those who have the experience and are willing to share – it can become very time consuming to answer every single question in detail. Not necessarily the case in all circumstances, and maybe not directly applicable here either - but something worth noting

    We’re all trying to be helpful though, and that’s the main thing - remembering the average Joe probably just wants a simple and to the point answer so he can get his bike running.
     
    • Like Like x 2
  19. kiffsta

    kiffsta Senior Member

    Messages:
    9,066
    Likes Received:
    6,872
    Trophy Points:
    1,168
    Joined:
    Aug 7, 2010
    Gender:
    Male
    Location:
    Brisbane
    Okay, an CBR250R MC19 engine is in fact an Honda MC14E engine, the MC22 also is an MC14E with very subtle differences. In order to get a MC19 engine into a 22, you will need to open the LH engine side cover and remove the pulse coil and trigger wheel and put the ones from your MC22 on there.

    There are subtle differences between the MC19 and MC22 engines, but MC22's will happily run with a MC19 engine if you change the trigger wheel and pulse coil. You other option is to move the MC19 electrics over, but then your air box wont fit under the tank.
     
    • Like Like x 1
  20. Mar7inez13

    Mar7inez13 Member Premium Member

    Messages:
    31
    Likes Received:
    7
    Trophy Points:
    18
    Joined:
    Jul 3, 2016
    Gender:
    Male
    Location:
    North Lakes
    My Bike:
    Honda CBR250RR
    Yes thank you i was aware of that not the full detailsso thank you, in saying that this has already been done and i have had the bike running before I pulled the carbys off again...
    When i ran it before i cant get it over 20-30kmh hence the rebuild
    Now is the tricky part
    Syncing the bad boy to run again
    With that said I was going to bench sync it last night but couldn't work out how to adjust the butterflies to open together
    They are all out of wack
    Cyl 3 is open with no throttle (but opens with cly 2
    Cyl 1 follows a little bit after (more throttle)
    Cyl 4 doesnt open till 3/4 full throttle....
    (Carby is on the bench)
     

Share This Page