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Project 3LN1 Restoration

Discussion in 'Your 250cc Projects' started by camarda, Mar 22, 2020.

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  1. camarda

    camarda Active Member

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    Hey guys quick other hurdle, see video for what I mean but it seems the float needle springs aren’t the best on these carbs. I forgot to mention that in the box with all the other parts there’s dissassembled 3LN1 carbs with no jets or jet housing or seals. But there are floats and float needles. It seems the float needles on these are much more “springy”. Luckily there’s 4 of them. Are the 3LN3 float needle springs less springy or are they worn and should I just swap them out, cheers.
     
    camarda, Apr 24, 2020
    #141
  2. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Keyster needle and seat spring's are much stronger than the original Mikuni one's
    My bike run's fine with them though

     
    my67xr, Apr 24, 2020
    #142
  3. camarda

    camarda Active Member

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    Oh, makes sense, should I chuck the keyster ones in then?
     
    camarda, Apr 24, 2020
    #143
  4. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I would just run the needle's with the softest rubber's, it'll most likely be the Keyster one's as they're newer
     
    • Agree Agree x 2
    my67xr, Apr 24, 2020
    #144
  5. camarda

    camarda Active Member

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    Sounds good, will do cheers @my67xr.

    @ruckusman what do you think of my adjust float height/fuel level reading contraption. Just finished it haha. What would I do without you. will need to put some nails or screws to stop the carbs sliding down. But it’s pretty much done.
    40E216E6-C9B5-495D-BB43-44366A4BEAC0.jpeg
    177492D4-7133-404A-AE09-FF6EC52EA064.jpeg
    EF3EAF3F-F30E-4E7F-8645-1B74C4D9C894.jpeg
     
    • Nice Work Nice Work x 1
    camarda, Apr 24, 2020
    #145
  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    You've got the carbs upside down, float bowls go on the bottom, diaphragm caps on top.
     
    • Funny Funny x 1
    Linkin, Apr 24, 2020
    #146
  7. camarda

    camarda Active Member

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    First pic is how they go on the bike 16 degrees on carb throat. Second two pic are for adjusting float height, the point where the tang just touches the float needle.


    Sent from my iPhone using Tapatalk
     
    camarda, Apr 24, 2020
    #147
  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Looks excellent, and yeah if you put two screws in at the right position you'll be able to almost wedge them in there for the adjustments/measurements

    I am looking forward to your first ride report as I reckon it will be so close to perfect in the all important carbs department that it should go like a rocket

    Guaranteed the previous owner never had it running right with their mish mash carb settings
     
    ruckusman, Apr 24, 2020
    #148
  9. Murdo

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

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    Using the needles with the strongest springs will make adjusting the settings easier.
     
    • Agree Agree x 1
    Murdo, Apr 25, 2020
    #149
  10. camarda

    camarda Active Member

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    Can’t wait for the first ride and to give a ride report. It will be so satisfying after all the work is done.
     
    • Agree Agree x 1
    • Love it! Love it! x 1
    camarda, Apr 27, 2020
    #150
  11. camarda

    camarda Active Member

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    Hey guys, litetek seal kit arrived today, will be installing it once I get the correct pilot housing seal from Blair.

    Anyone here an expert on brake caliber grooves, I have spent bloody hours trying to clean them, ended up using a mildly acidic ultrasonic solution/ nylon Bremel head to get them clean but I’m unsure how good they need to be. All the crud is out but there seems to be a blackish oxidised layer on the inside of the grooves on some of calipers, it isn’t raised, just discoloured. Also there seems to be some light scratches on the surface of the grooves on some calipers, will this negatively affect them.

    This is Before:
    [​IMG]

    This is after with Oxidised discolouration.

    [​IMG]
    [​IMG]
    This is the Light scratches.
    [​IMG]

    I have brand new seals for them but I don’t want to install them if I need new calipers.

    Thanks again guys, appreciate it.
     
    camarda, Apr 29, 2020
    #151
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    That's just discolouration, if you want to you can make it shiny with warm/hot diluted citric acid (teaspoon in ~500 mls) and a green (not metal) pot scourer, but that is getting very fussy - they look to be quite OK
     
    ruckusman, Apr 29, 2020
    #152
  13. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Threebond Super Engine conditioner is also good for cleaning alloy component's, use a small toothbrush style brass wire brush

    I have also used Rust Off for cleaning alloy's with a brass wire brush, good for removing stain's
     
    • Informative Informative x 1
    my67xr, Apr 29, 2020
    #153
  14. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    @camarda I sent you a PM about those seals you need.
     
    maelstrom, Apr 29, 2020
    #154
  15. Murdo

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

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    Looks fine. Just make sure you put some rubber grease in the grooves to help the seal 'settle in' and more on the piston side too.
     
    • Agree Agree x 1
    Murdo, Apr 30, 2020
    #155
  16. camarda

    camarda Active Member

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    Going to need to adjust the float levels again, are you guys sure it’s 14.7mm, I’m getting about 6mm fuel level, Will need to do some more adjusting. Going by @ruckusman maths (25.2) would equate to about a 19.2 mm float level. Seems too high. [​IMG]
     
    camarda, May 5, 2020
    #156
  17. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yes a float level of 19.2mm is way too high as a 6mm fuel level is very low and therefore lean

    So the sum of float level and fuel level will be 25.2mm, so as one reduces the other will increase

    3LN3 carbs run 10.5mm fuel level, therefore 14.7mm float level

    EDIT, IIRC, you had the choice of the older OEM needles which would the very likely have worn &/or cracked rubber tips, stick with the new keyster needles, just be aware that they may be influencing your measurements

    I will add that is with OEM needles and springs, so if you need to raise that fuel level 4.5mm - take that amount off of the current float level, measure where it is, take note, then adjust 4.5mm lower then remeasure the fuel level.

    Fuel level is your ultimate goal here
     
    ruckusman, May 5, 2020
    #157
  18. camarda

    camarda Active Member

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    Ok, I think it might be the 16 degree angle, I think it’s angled more than 16 on the bike, how did you get that angle @ruckusman .
     
    camarda, May 5, 2020
    #158
  19. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I measured it with an engineering protractor which has a ruler and bubble level

    It's relatively quick to put the carbs back into the rubber manifolds and measure that way

    I don't know why I didn't think of it at the time, I could have used an app on the phone to measure the angles of the rubber manifolds
     
    Last edited: May 5, 2020
    ruckusman, May 5, 2020
    #159
  20. cornulio81

    cornulio81 Active Member

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    Have not almost all Mikuni carbs a float high of 13-14mm, measuring the highest point of the floater 90° from the bottom?
    I also set up sth. in the past to get the carb in the correct angle like the bike, but measuring on open carbs is much easier?!
    But you have to fixing the float cover like in this example I found, to measure correctly
    [​IMG]
     
    cornulio81, May 5, 2020
    #160
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