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How I Fixed My Broken Float Post Mount Tab Ear Pin Thing

Discussion in 'XJ Technical Chat' started by Rice_Burnarr, May 13, 2009.

  1. Rice_Burnarr

    Rice_Burnarr Member

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    I pulled the Mikunis off my SECA 550 for a rebuild because I've had a float stick a few times. The good news is that I found the smoking gun. One of the floats was hanging up on the inside wall of the bowl and sticking intermittently. I can see some small marks on the float and the bowl wall where the contact was occurring. The bad news is the reason the float was able to move that far to the side was because one of the float pin posts had been broken off by someone else in the past.

    The other bad news is that I bought this bike brand new and am the original owner. The carbs have never been off before and nobody has ever been inside that bowl except me.

    So this means that the mother effin, slimeball, cheatin, rat bastard Yamaha dealer that I bought this "new" bike from was a lying, untrustworthy, deceptive SOB that should rot in hell forever. Yes, that's right... My "brand new" bike came with used carbs on it? Worse yet, used carbs with shite BROKEN inside??? The busted off part was not inside the bowl, so I know it didn't happen while riding. Some of the screws were buggered. Some of the jets were a little smeared... Makes me wonder what ELSE on the bike was used? :twisted:

    Anyway, I'm trying to look at it realistically and remind myself that I've never been disappointed in the quality of the bike until now, and if I'd never dug into the carbs, I'd never have known... Still pisses me off, but I'm trying to get over it. Deep breath...

    So back to the sticking float and the broken float mount post. Here's what I did to fix it...

    First, I filed the busted post off square and flat:
    [​IMG]

    Then I marked the center of the stub that remained:
    [​IMG]

    Drilled it out:
    [​IMG]

    Made a replacement post tip:
    [​IMG]

    Fit lightly into place:
    [​IMG]

    Pressed the pin all the way home, and also cross-drilled for a retaining pin (a small brad nail). The replacement tip was a pretty tight press fit into the post stub and the cross pin probably wasn't necessary, but I'm a belt and suspenders kind of guy:
    [​IMG]

    I filed the replacement tip flat to make room for the float and drilled the hole for the float pin:
    [​IMG]

    Done. Good as "new":
    [​IMG]

    Burnarr
     
  2. SQLGuy

    SQLGuy Well-Known Member

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    Nice work! That's definitely the way to do it right... that or tap the hole and thread the post.

    Can you tell us what tools you used to make the post and file it flat. I suppose a lathe for the former, but was the filing done carefully and by eye, or do you have some setup to file a flat like that?

    Thanks,
    Paul
     
  3. ethanch

    ethanch Member

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    Nice piece of fabrication there. I probably would have pinned it to or drilled and tapped for a set screw. Did you use some off the shelf bar stock or did you have to turn the whole piece down to fit.
     
  4. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    DUDE! Damn machinist anyway. VERY nice work.

    You didn't buy a bike with used carbs. XJs (550 Secas for sure, and others I'm sure) had a problem with RUST IN THE TANKS right from the factory as a result of the sea voyage and long time spent sitting pierside.

    There were a series of service bulletins instructing the dealers on dealing with rust in the tanks, including carburetor removal and cleaning and even tank lining in extreme cases! I will try to dig one up and post it if I can.

    The real rat bastard was the inexperienced pimply-faced setup snoid who broke your carb; the dealer probably never had the slightest clue.

    +1 on your fix. Nice clean work.
     
  5. Rice_Burnarr

    Rice_Burnarr Member

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    Thanks guys. Glad it meets with the approval of the clan. I was worried that everyone was gonna come back and say "Big deal, why didn't you just JB weld it?" and I was gonna get into this whole thing about it.

    The replacement post tip was made in a lathe, and the holes were drilled in a drill press, but all the filing was done very carefully by hand and eye. The aluminum stock I used was a little oversized so I turned it down to the larger OD first and then turned the smaller end down more. The OD of the remnant stub is like .270 so unfortunately off the shelf 1/4 inch stock is a little undersized. I think I used 5/16 stock or 3/8 stock to start. I mean, once it's in the lathe, that's trivial.

    ethanch, The idea of threading it together crossed my mind. I thought about running a tap into the post stub and threading the smaller end of the replacement tip, but I decided that a press fit would be easier if I (shudder) have to go back in and mess with any of it again. Well, that and the absolute LAST thing I wanted to do was break off a small size tap in the gummy aluminum carb body... 8O But assuming you don't break anything, threading would be a good option too.

    And bigfitz52, thank you very much for the insights on rust issues in transit. That helps my mental state a lot. :D I'm going to continue lovin my SECA and I'll go with blaming the pimply-faced setup snoid. That really makes things easier for me.

    Now the breaking news (get it? "breaking" news?) is that I've got another one to do, and this one is at least partially my fault. You see, there is another carb that had a post a little BENT, but not broken off. The bent post was throwing the float alignment off in that carb as well. It wasn't enough to rub the bowl wall, but it may have been enough to bind the float a tiny bit. Anyway, it was bugging me, so I tried to straighten it.

    Didn't work. :x I guess I should have left well enough alone.

    Good news is it's the other side that doesn't have the float limit travel tab and I've got another way to fix that one that's a little less complicated. I'll take some pics during that surgery as well.

    Burnarr
     
  6. knight_007

    knight_007 New Member

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    I had the same problem with the two carburators of my bike and lucky enough those broken pieces were still in there stuck in by the previous owner with arldite which ulimately dissolved in gas and fell apart.
    The J B WELD did the trick and so far so good!
     
  7. bill

    bill Active Member

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    Great resolution of a fairly common problem. Since you mention JBWeld I wondered why you didn't JBWeld in the post in to the tube. Beautiful work I don't have the tools or skills to that kind of work.
     
  8. schmauster920

    schmauster920 Member

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    I like the fix... if it was threaded, you would have to deal with possibly stripping the aluminum threads.. if it turned at all, it would bind with the pin, theres just a lot more to go wrong..

    I would have added a little jbweld where the post goes into the carb to make sure it doesnt turn, but im sure everything will be fine as it is... at this point its removable so thats not a bad thing either
     
  9. dpawl31

    dpawl31 Member

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    *cough* FAQ *cough*

    Congrats on the fix, uh, and sorry for the new problem. hah.

    Bet you can't wait to get tweakin those carbs and have a 'brand new' bike again!
     
  10. Polock

    Polock Well-Known Member

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    sometimes ya feel round, sometimes ya feel square
     
  11. wizard

    wizard Active Member

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    That's some dovetail, Polock.
     
  12. MN-Maxims

    MN-Maxims St. Paul Minnesota

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    Nice work on the float pin post. I have a problem wit Mukuni making the float pins so you have to punch them out. I was measureing the inside of the float bowls and why couldn't a guy just install longer float pins so the carb bowls would hold them in like the Hatachi carbs do. Just thinking of avoiding what you just went through.

    MN
     
  13. Rice_Burnarr

    Rice_Burnarr Member

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    The replacement tip I made is a medium press fit into the hole in the remnant stub. I didn't have to go whole hog on the press to get it in there, but it's sure not what I would call "replaceable", and it's certainly not going to fall out by itself. But it's in there tight enough that JB weld isn't necessary there. As a matter of fact, JB weld in that hole would have made it impossible to press the replacement tip in because it won't compress. I would have had to drill a vent hole at the bottom for the excess JB weld to escape. :lol:

    The cross pin probably isn't necessary either, but I was on a roll. It's simply a redundancy feature for "insurance". :D

    Nice dovetail Polock!! You're a square.
     
  14. Rice_Burnarr

    Rice_Burnarr Member

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    You know... Now that you mention it, I've also seen that method employed in other carbs in the past as well. Kinda makes you wonder why Mikuni didn't do that, or why it couldn't be done as a retrofit. :?:

    The pin wouldn't have to be significantly longer. As a matter of fact I was test fitting stuff together earlier today and I was having a little trouble getting one of the carb bowls lined up. The reason was that I had the float pin just barely pressed into place (because I knew it was coming out again) and with that pin not pressed all the way home, it was hitting the inside of the bowl casting.

    Hmmm...... :idea:
     
  15. Rice_Burnarr

    Rice_Burnarr Member

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    Remember the other broken post? Here's what I did with that one...

    This post was the other side and in a different carb:
    [​IMG]

    And this one does not have the same travel limiting feature as the other side. You can see here that the other side needs to be taller because the tang on the float contacts it when the float hangs down. I don't know if it really matters once the bowl is on, but this tang on the float is why I went through such pains with the first one:
    [​IMG]

    Since this one wasn't complicated by that travel limit tang, I did something simpler. I drilled a small hole and fed a piece of wire through the hole:
    [​IMG]
    The hole I used here is a little smaller than the one for the locking pin on the other side, so if I do have to go ahead and do this one the same way I can drill the hole out a little larger for that more complicated method.

    Put in the pin, twist up the wire, cut it off, and you're done:
    [​IMG]

    Simpler? Yes. Effective? Yes. Cheesier? Absolutely! Rated for continuous use submerged in gasoline? Definitely! And it only took about ten minutes start to finish.

    I cannot take credit for the idea on this one. This fix was employed in the donor carbs I got for messing around with before I tackled my "good" ones. Works for the posts on that side, but I wouldn't want to use it on the other side.

    Burnarr
     
  16. bill

    bill Active Member

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    Inventive for sure - great pics too - I have trouble getting closeups that nice. I usually blame the camera
     
  17. JoeFriday77

    JoeFriday77 Member

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    Very impressive fabrication. Like your attention to detail.
     
  18. mcrwt644

    mcrwt644 Member

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    yes, impressive indeed. any way you could fill us all in on exactly what equipment was used, measuring techniques and whatnot? Nice job all around
     
  19. midnightblu

    midnightblu Member

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    nice work.... uh except the one with duct tape and bailing wire :)

    polock you wood worker :) you certainley have more paitence than i .... i would have opted for the round method - it looks easier
     
  20. Tman_74

    Tman_74 Member

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    WOW, WOW, and WOW. We have an awesome group of people here!!!!!!!!!
    I like the bailing wire, more my level ;)
     

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