The XL600 thread

Discussion in 'Thumpers' started by Gregster, Jul 6, 2007.

  1. sh0rtlife

    sh0rtlife Long timer

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    .5 is NOT max over.but might be max for OE slugs?..i know to get a "quality" slug i had to go BIG bore i want to say i went 3mm over but its been too long, and had my jug bored out to match...my first set of rings fit like garbage, kinda like yours..the second set they sent me fit perfect....so its possible whoever put it together used the wrong rings its a question of was it what they were given and didnt know better or ordered the wrong parts in the first place

    my cam doesnt look too far off from yours...and hasnt given me a lick of issues..and i KNOW mine got hot....since i personaly blew the previous slug

    with said heat..take a GOOD look at the bottom end and see how things look
  2. bork

    bork Been here awhile

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    Remember to get all the copper seal/washers on sub-rocker arms & the decompression shaft & the small special oil seal on the 5th valve. And IIRC the cam tension-er shaft has a slightly different size o-ring depending on year.
  3. bork

    bork Been here awhile

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    The numbers do change over the years. Dont know what was changed. Chart for comparison >>>
    [​IMG]
    [​IMG][/URL] [​IMG][/IMG]
  4. sh0rtlife

    sh0rtlife Long timer

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    the only thing i know for sure on the carbs is that the bowl shape changed
  5. peuk92

    peuk92 n00b

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    Hello all,

    Does any of you know where is going the big needle on a XL600 LM carburator? I buy it a month ago but i've got a leak of petrol from carburator and the last owner rebuilt it approximatively so before reassemble the carburators in the engine i would like to be sure which needle is goign where. If any of u get the information i will be greatfull.

    Regards
  6. sh0rtlife

    sh0rtlife Long timer

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    10-1 odds are your leak is impropper float lever..use clear fuel line off the drains held up the side of the carb, open drain and see where it sits, it needs to be BELOW the gasket line but not by much

    the other likely issue of a leak is the o-rings on the fuel rail connection pipe that ties the 2 carbs together

    as far as the big needle goes...im not sure what your asking
    peuk92 likes this.
  7. benspilk09

    benspilk09 Adventurer

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    Is anyone able to ID this piston? I'm assuming it's an OEM one, but I want to make sure before I drop $70 on rings. It measured 100.469mm, so I'm assuming it's a 0.5 over stocker.

    My bore checked out great at the machine shop, almost zero taper or out of round so we were convinced it was freshly bored, and he hit it with a hone.

    One of my rings already has a "50" stamp on it, but as I said the ring gaps are way too big. They do not appear to have been filed. The bore and piston to wall clearance is good per the manual, so I'm hoping to ring it and put it back together with new seals and gaskets and have a healthy engine.

    There are marks where the valves have hit the piston, I guess it has been repaired because the valves are undamaged and are holding compression.

    Attached Files:

  8. peuk92

    peuk92 n00b

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    Thank you very much for those advise. Effectively the o-rings on the fuel rail connection are a bit old. I will replace them before monting the carburator.

    For the needle a picture is more explicit than words. I mean you've got to different carburator. Primary and secondary. Both of them got needle but different. And i'm not sure about the place of them. The big one in primary or in secondary or inverse

    Regards
    [​IMG]

    Attached Files:

  9. sh0rtlife

    sh0rtlife Long timer

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    hmm im 99% sure that both of my carbs use the same needles, so its possible the kit youve got is wrong?...not sure
  10. bork

    bork Been here awhile

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    The one on ebay looks identical? https://www.ebay.com/i/224206744804...1291&msclkid=a2bb552dc3c21f5103a30afc559dfcc4
  11. benspilk09

    benspilk09 Adventurer

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    It does look identical, the only thing that made me second guess it was that some oversized Honda pistons have the "25" or "50" stamped on top. Mine has no such marking.

    I guess they're probably the only ones that made this size. I'll go ahead and order rings for it.

    Side note, does anyone have any clever ways to leak test the valve guide O-Rings while I have this thing apart? I'd like to eliminate any possibility of oil consumption.
  12. sh0rtlife

    sh0rtlife Long timer

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    the only way i know is to build a CC'ing plate and test via compression.....honestly youd likely be better off just replacing them if you suspect them..call it piece of mind maintenance

    heck you allready have it this far apart, and theres valve marks on the slug...you would kinda be stupid to not pull the valves and check them and the seats anyway...at which point new seals is just a no brainer
  13. peuk92

    peuk92 n00b

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    Damn, the problem is it's not from the kit... It's how I get it when I buy the motorcycle...

    Which model have u hoy?
    Mine is a ph69a from a 600 XL LMH 87

    Does any other remember it?
  14. Fingers

    Fingers Been here awhile

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    Peuk92, the ph69a carburetor came with 2 different needle jets. Part numbers are 16012MK5651 (Primary Carb) and 16027MK5681 (Secondary Carb). I do not know what the difference between the two are.
  15. benspilk09

    benspilk09 Adventurer

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    I am planning on inspecting the valves and seats when I replace the seals, I just hate to pull the guides out and have a fortune in a complete valve job if the O-Rings aren't even bad. I really don't think it would have run as well as it did if the valves were bent, and they show no visual signs of piston contact.

    I'm guessing the person that did this top end job bought the piston used from someone who's engine jumped time and parted the bike out.
  16. bork

    bork Been here awhile

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    Ive never heard of anyone having issues with the guide o-rings, because the guide is a tight fit. I'd almost think a person could run without them. That is a little odd on the piston marking or should I say no-marking? Being it looks so clean, I'd measure it out and go by the SM tolerances. Come to think of it, I might have an old piston. I'll see if I can find it and report back.
  17. sh0rtlife

    sh0rtlife Long timer

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    i almost belive the o-ring seals are just to hold the guides in place durring assembly more than anything or more of a "just encase"
  18. benspilk09

    benspilk09 Adventurer

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    I had the piston measured when I had the bore checked, its a 50 over piston for sure. The piston to wall clearance is within service limits in the manual so I'm going to run with it. I just want to be sure I don't have some oddball aftermarket piston that wont accept oe rings.
  19. benspilk09

    benspilk09 Adventurer

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    Is the plug covering the rear head bolt required on an 84+ engine? I don't see what purpose it serves without the reed valve like an '83 has.

    The bozo that put this engine together last installed it upside down, so I had to drill a hole to remove it. Luckily it wasn't stuck and it came out with a pick.
  20. peuk92

    peuk92 n00b

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    Thank you very much for this precision. I can telle the small one is going in the primary and the big one in the secondary. I just rebuilt it and it's working well!

    You were right I had a bleed in the secondary cuve. With your method I fixed it easily. Thank you so much!