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Project Grasshoppers FZR 3LN3

Discussion in 'Your 250cc Projects' started by GreyImport, Feb 16, 2014.

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  1. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    3LN1

    carb 1.jpg

    3LN7

    carb 2.jpg
     
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    GreyImport, Feb 12, 2015
    #221
  2. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    Received another set of carbs today in the mail.. yeah! Checked the needles... turned the pilot screws 2.5 turns, took current carbs off, installed these and whammo! No flat spots, just screams all the way up the range, and much better low end torque.. These came of a race bike.... PO did tell me it does sometimes stall at below 2000 rpm... but... these carbs are a major improvement. These will do until I do a major rebuild of a set... Now I can ride pretty much without hassles...:dance2:
     
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    Grasshopper, Feb 13, 2015
    #222
  3. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    @MashtX
    It is not that simple. What happens is that there is a pulse occurring in the inlet tract. This means that there are a host of variables that are involved in the process of trying to get the correct mixture into the cylinder. Best not to compare jet sizes between bikes or it will drive you nuts.
    Cheers
     
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    maelstrom, Feb 13, 2015
    #223
  4. MashtX

    MashtX Well-Known Member

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    Fair enough, I genuinely don't understand carbies. They are just black magic to me haha!
     
    MashtX, Feb 13, 2015
    #224
  5. Phil

    Phil Senior Member Contributing Member

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    Good for you, nice when a plan comes together :thumb_ups:.........god knows it doesn't happen that often.
     
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    Phil, Feb 13, 2015
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  6. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    My Bike:
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    Fizzer Factory Update: Been riding every day... bike seems to hesitate at times, other times it doesn't - seems electrical. Grey and I took off the fuel tank, drained the fuel, and saw old bits of rust and dirt come out of the tank (tank looks ok inside). So we flushed out the tank and cleaned the tank filters. Also took the fuel filter off and noticed 2 things: 1) It was installed the wrong way around :headbang:, and 2) It was very dirty. Replaced it for $3.50. Bike ran a little better after that!

    But, the real difference was when we changed the plugs, and fixed up the leads (snipped a bit off the spark plug end off each lead). Put new plugs in ($22.50) and whammo!

    Since we changed the plugs and fixed the leads - it's like a different bike, so smoooooth, starts every time and it really flies.... you need to ride it... This was based on me just riding to the station and back all I can say is WOW. :thumb_ups: The old plugs looked tired, gap too wide....
     
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    Grasshopper, Feb 20, 2015
    #226
  7. Phil

    Phil Senior Member Contributing Member

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    Great news, as is so often the case it tends to be the most obvious issues that get things running properly. Pleased to hear all is well, well done fellas and of course.............enjoy the ride :thumb_ups:
     
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    Phil, Feb 20, 2015
    #227
  8. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Today's game... odd one out!

    [​IMG]
     
    Linkin, Feb 26, 2015
    #228
  9. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    CHUGGING PROBLEM SOLVED (ie: bogging down, flooding at lower revs, eg. after accelerating and then stopping at lights etc.). This seems to be common problem on these carbs, as the Jet needle and emulsion tubes wear out, and are rarely replaced by anybody it seems these days.

    Here are some pics of what was done. I will do a proper write up soon re: changing the emulsion tubes and needles for those that may want the procedure:

    Removed the bowl cover, undid the brass bolt on the right which holds the emulsion tube and plastic holder
    image(25).jpeg

    Removed the other cover and jet needle, spring etc.
    image(26).jpeg

    After gently tapping the tube out... usually the whole unit comes out like this...
    image(27).jpeg

    Next we separated the tube from the plastic holder, and inserted the new emulsion tube, the new needle is shown too
    image(30).jpeg

    Plastic holder and emulsion tube inserted back into carb, very easy, you can see the new emulsion tube
    image(31).jpeg

    Here's the other end shown, it is keyed, and must go in the correct way when you push it onto the plastic holder, and then into the carb. You can see where the bolt goes.. and not too tight!
    image(32).jpeg

    And now, the apprentice celebrates, since I did all the work!!
    image(34).jpeg

    Lucky we had the proper Elixir on hand to assist the process
    image(33).jpeg

    The first thing I noticed, is that the bike takes off properly now at low revs - you don't have to rev the B-Jesus out of it to get going, and.. no flooding at all. I think it's running real lean, so need to adjust the pilot screws... all seems good!! @maelstrom
     
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    Grasshopper, Mar 7, 2015
    #229
  10. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Good stuff, can't wait to do mine
     
    Linkin, Mar 7, 2015
    #230
  11. Joker

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

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    Did you keep the needle setting at stock (3 notch down) or are you running slightly lean (2 notch down)? On your new needle it almost looks like you're running the leanest setting (top notch)?

    Just curious :)
     
    Joker, Mar 7, 2015
    #231
  12. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Well done Mr Grasshopper and Mr Grey.
    I suggest only changing mixtures by 1/4 turn at a time and set them when the engine is warm after going for a short ride.
    Of course when the engine is cold it wants to be richer but if you set the mixtures from cold the engine will stall once it is up to operating temp. They are fuel screws so the 'N' turns out is only a guide. The optimum setting may not be the same on all cylinders also but I am not going to go into that. You have to find what works best for your bike.
    Maybe you guys can send me your old emulsion tubes :)

    @ruckusman Have to try this on your FZR.
     
    Last edited: Mar 7, 2015
    maelstrom, Mar 7, 2015
    #232
  13. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    1/4 turn was my suggestion also Mr Green

    And as for the stock setting for the clips and pilots screws I cant say I can remember seeing anything on paper that has appeared in a genuine manual or spec sheet

    A lot of info , as we know , is just hearsay handed down from generation to generation and forum to forum ... with a side dish of snake oil

    The available English spec sheet for the 3LN7 I take with a grain of salt

    The 3LN1 supplement is a little vague

    Im presently studying the 2KR manual

    Mr Green ....

    If the needle has 5 positions is it logical to assume the centre position #3 is the 'stock' setting?

    Would the 26 carbs on the 2KR carry the same settings as the 28s ?

    Or the 32s on the FZR400?

    We have 3 more sets of carbs to dig into (including my originals) ..... lots of tubes!
     
    GreyImport, Mar 7, 2015
    #233
  14. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    Ok sounds good Blair. Yep we can send you some emulsion tubes. It's actually scary how fast these bikes can go....:prankster:, but then I guess many of you are used to faster bikes.... Every time we tweak, fix an issue etc. - Wow... Regarding the needle setting, I put it on the 2nd from the top... maybe should have done 3rd, but we'll see... I don't know what the stock setting actually is. I set it to what I thought was correct. I'm thinking it may be ok, especially with a fine tune on the pilot screws... will play in the next few days....
     
    Grasshopper, Mar 7, 2015
    #234
  15. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    If the needle has 5 positions is it logical to assume the centre position #3 is the 'stock' setting?
    Correct

    Would the 26 carbs on the 2KR carry the same settings as the 28s ?
    I doubt it. Completely different carbs.

    Or the 32s on the FZR400?
    Not very useful. I have the 3TJ1 supplement now but like the 3LN1 it is in Japanese.
    The FZR400 1WG manual is completely useless, like the 2KR, different carbs.
    With Stu's help we should be able to decipher any unknown information from the 3LN1 supplement and the parts book.
     
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    maelstrom, Mar 7, 2015
    #235
  16. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    maelstrom, Mar 7, 2015
    #236
  17. Grasshopper

    Grasshopper Well-Known Member Dirty Wheel Club

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    Ok, I will probably remove the carbs again soon (sigh) and set the needles to position 3 and report the result in a couple of days.
     
    Grasshopper, Mar 7, 2015
    #237
  18. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Would be good to get used to riding it as it is first Grasshopper. Take it for a run to somewhere where you can cruise at half throttle so the comparison is more accurate.
     
    maelstrom, Mar 8, 2015
    #238
  19. Joker

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

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    You may find position 3 is worse, that's what I found with mine.
     
    Joker, Mar 8, 2015
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  20. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    These are brand new parts .... therefore its logical to me to set them at stock to begin with.
     
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    GreyImport, Mar 8, 2015
    #240
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