XT550 "hop up"

Discussion in 'Thumpers' started by CharlieP, Feb 9, 2010.

  1. CharlieP

    CharlieP Been here awhile

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    Can 600 jugs and pistons go on a XT550 ??

    Any other "hop ups" ??
    #1
  2. brucifer

    brucifer Long timer

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    Yes. Both Wiseco and JE have high compression and/or big-bore piston kits for the 600.
    Web and Megacycle have performance cams. You're pretty much on your own with the exhaust.
    Carburetors? Unfortunately you're stuck with the stock ones. I haven't been able to locate any jets other than the stock sizes.
    Sudco used to sell a nice set of Kei-Hin CR smoothbore carbs for the 600 but they were a real pain in the a$$ to install. You had to cut and modify the fuel tank to clear the throttle assembly. I went through two tanks on a TT600 I had back in the mid '90s trying to get them to seal after the mods with no luck. Finally bought a new tank and went back to the stockers.
    I have heard of people installing Yamaha Raptor quad carbs on the 600s but I have no experience with this.
    #2
  3. G600

    G600 Been here awhile

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    Do you mean "Yes, the jugs and pistons from an XT600 will fit the XT550"?
    #3
  4. brucifer

    brucifer Long timer

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    Yes. The XT and TT600 pistons and cylinders will bolt onto the XT550. The only difference between the two engines internally is the bore. The stroke is the same.
    BUT Yamaha changed the bolt pattern on the 1990 XT600E cylinder or head, I don't recall at the moment, so it and the later versions won't work.
    But you're good to go with the 1983-1989 models. :thumb
    #4
  5. Zecatfish

    Zecatfish XTique Rider

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    The TT600 header will fit the XT550 frame, almost. :D
    You need to source an allen head bolt and replace the drain plug in the down tube. That is the issue I have with mine.
    I used a whole TT600 engine.
    Webcam's will regrind your stock cam for around $190. I've seen a few reports of those that have tried it and thought the OEM clutch was a little weak for the added HP.
    #5
  6. G600

    G600 Been here awhile

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    Interesting. Great thread.

    I recently bought a '83 550. It needs lots of work and it's hard to start... but I hope I can get in good shape...

    Since the 600 engine is the same (except for the bore) as the 550, engine parts should be easier to find...

    [​IMG]
    #6
  7. Flatulator

    Flatulator Banned

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    Let me guess ... you are young and its a first bike for you ?

    OK .. I know its "your bike" .. and you can do whatever you want with it ... but why the heck 'hop it up' ?

    Have you ridden it yet ?

    If it is simply running the way it should - as it came out of the box ... it is plenty fast as is ... I bet is every bit as fast as a KLR650 (stock/stock) ... not that that is "fast" - but its fast enough to get you in trouble.

    ... and mods are quite expensive and time consuming ... and need to be done correctly or it gets REAL expensive

    you can buy big bore kits ... (w or w/o high comp) ... cams ... race exhaust (downpipes) ... including labor - that'll be well over $1000
    #7
  8. Zecatfish

    Zecatfish XTique Rider

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    There is other differences.
    The TT600 has larger exhaust ports, and larger header.
    The TT600 has a different kick starter ration than the 550.
    The TT600 has a lighter flywheel, and a 6v a/c only stator.
    The TT600 might have different gearing.
    the XT/TT600 has a better counterbalancer for less vibrating.
    I read someplace the XT600 head has different oil passages so you might have to change the jug and head a unit.
    The TT600 uses a different intake manifolds.
    Jetting is different too. That extra 30cc on the TT600 with the 550 carb on it makes it cold natured hard to start when cold. It seems a bit lean on the main too and I have a little pinging under 1/2 to full throttle loads.

    Just be advised its not as simple as it seems.
    Good Luck.


    #8
  9. yroabob

    yroabob n00b

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    1984 to 1989 XT and TT600 cylinders wont bolt onto XT550 without machining 3mm out of the crankcase.I have just done this mod to my 550.
    Take 3mm out then it bolts on no worries.:clap
    #9