1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Pieces of black plastic in gearbox

Discussion in 'XJ Technical Chat' started by DimaV, Jul 10, 2017.

  1. DimaV

    DimaV Member

    Messages:
    46
    Likes Received:
    2
    Trophy Points:
    8
    Location:
    Kyiv, Ukraine
    Sup, guys!
    Once upon a time (a week ago) I drove my motorcycle (yamaha xj650 seca) uphill. Switched to the first gear to easily climb up. When I decided to accelerate I couldn’t! My gearbox stuck on first gear. Couldn’t get neutral ether.
    Decided to remove engine and look on gear switcher and gear box. Switcher was fine but in gearbox I found the problem. A few pieces of black plastic was stuck between gears and blocking them.
    Question : what could it be? If someone disassembled this engine, u probably know where it from.
    Thanx for a feedback.


    PS : i guess its a part of camshaft drive chain...but why it cracked and whats steps I have to take futher (dissasanble engine or not)
     

    Attached Files:

    Last edited: Jul 10, 2017
  2. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
  3. Quixote

    Quixote Active Member

    Messages:
    172
    Likes Received:
    35
    Trophy Points:
    28
    Location:
    Victoria, BC, Canada
    XJ550H beat me to it.
    It's the alternator chain guide. The good news is that the part is not expensive, the bad news is that you have to split the cases to get to it. If you can clear out the bits, you can ride the bike for a while but you really should replace it soon or else the loose chain will start doing damage inside your engine.
    This is a very common problem on these bikes. Search "alternator chain guide" in these forums and you'll find lots of people who have had the same problem (myself included).
    It's a big job, but not impossible if you are mechanically inclined and it sounds like you already have the engine out of the frame so if I were you I'd just dive in and do it.
    Make sure you have the manual before you start.
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
  5. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Is that like neutral spirits?o_O
     
  6. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    Along with the alternator chain guide you should also inspect and rebuild the starter clutch. Also, the front bolt on the chain guide is easily broken, so use heat and lots of care to avoid that dilemma. Here is a fairly recent link on the procedure that recommends using Loctite instead of the Yamabond to seal the cases:

    http://www.xjbikes.com/forums/threads/splitting-the-cases-to-do-list.108285/

    And a good link with lots of photos and suggestions on removing the motor:

    http://xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/#post-336108

    A FSM is important, you want to be sure to follow the sequence on loosening and tightening the case bolts to avoid warping and damaging the cases.

    Most will recommend leaving the top end in place, but that really depends on the condition of the motor (and maybe budget) to determine if you should remove the head and jugs to replace gaskets and parts.
     
    TheCrazyGnat likes this.
  7. DimaV

    DimaV Member

    Messages:
    46
    Likes Received:
    2
    Trophy Points:
    8
    Location:
    Kyiv, Ukraine

    Thank you for your advice, will try to split the cases with mechanic and look what happened. 19 000km of original mileage seems true. Engine and motorcycle itself in awsome condition. Couldn't thought that something like this could happen.[/QUOTE]
     
  8. DimaV

    DimaV Member

    Messages:
    46
    Likes Received:
    2
    Trophy Points:
    8
    Location:
    Kyiv, Ukraine
    Thank you. Look through
     
  9. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    It is pretty common. It is not really mileage related, but more about the age and the rubber drying out and weakening. The good part is it not too expensive to repair, I know I need to do the same thing as I see bits of the rubber from the chain guide when I do an oil change and pour the oil through a filter.
     
  10. MattiThundrrr

    MattiThundrrr Not a guru

    Messages:
    3,690
    Likes Received:
    1,665
    Trophy Points:
    113
    Location:
    America's friendly hat
    The plastic guide seems to break down with age, not necessarily mileage. It is a 35 year old piece of plastic that's sitting in oil.
     

Share This Page