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.

Tyler643's 81 JX650

Discussion in 'XJ Technical Chat' started by k-moe, Sep 26, 2019.

  1. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    10,893
    Likes Received:
    2,988
    Trophy Points:
    113
    Location:
    Great North Woods
    https://www.xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/

    you could start by removing oil pan and looking at the gears
    trans.PNG
    doing guideectomy you look in this hole behind shifter cover
    guide.PNG
    with oil pan off you could flush it out from this hole and from oil pan side
    then look at what comes out. if your chain guide has failed you Have to replace it before oil nozzle is cut down by chain.
     
    Last edited: Dec 13, 2019
    Simmy likes this.
  2. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    10,893
    Likes Received:
    2,988
    Trophy Points:
    113
    Location:
    Great North Woods
    would not bother with this motor. get a whole one. if you look up the cost of splitting motor all the gaskets a used motor makes more cost sense. and you could buy a 750 motor and put it in your 650 frame

    then you have a motor to explore and may be fix. when you do the chain guide you should also change out the starter clutch
     
  3. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    I gotcha. I'll have to do some digging when I get some time. But I did find a 81 650 that had 16900 miles that I'm thinking about getting and taking the good parts from both and making one really good bike. Because that one needs carb work. But my carbs are really good and working great. If I do that is there anything you'd recommend doing. Or just swapping the engine?
     
  4. hogfiddles

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

    Messages:
    12,394
    Likes Received:
    3,752
    Trophy Points:
    113
    Location:
    near utica, new york
    Engines are plentiful
     
  5. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    I found the problem. It hydro locked. There was a ton of gas in the oil. I have started getting ready to pull the motor. But have a question. Is it better to disconnect the final drive at the u joint or pull the whole drive shaft out? Thanks for the help
     
  6. hogfiddles

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

    Messages:
    12,394
    Likes Received:
    3,752
    Trophy Points:
    113
    Location:
    near utica, new york
    If the engine is full of gas oil, just open the drain and empty it
     
  7. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    I have drained all the oil. But there is a crack in the block. That is why I have to pull the motor
     
  8. hogfiddles

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

    Messages:
    12,394
    Likes Received:
    3,752
    Trophy Points:
    113
    Location:
    near utica, new york
    Oh—- that’s a whole lot more than hydrolock!
    I’ve never even heard of an xj hydro-locking, either. My bet is something else catastrophic happened.
     
  9. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    I don’t see how it wouldn’t be hydro lock. Because the oil was more gas consistency than oil consistency. But I’m no mechanic either. What else would it be with that much gas in there?
     
  10. hogfiddles

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

    Messages:
    12,394
    Likes Received:
    3,752
    Trophy Points:
    113
    Location:
    near utica, new york
    If the crankcase is filled right up, the liquids will push through the black tube on the left cover and flow up to the airbox will it will then drain through the small tube to the floor.

    First off, hydro locking is primarily a “water filled a cylinder” issue. Rarely a gas/air mix issue. You’d almost have to have an injector fail and pump massive amounts of gas into a cylinder. Or, have head gasket fail and allow a cylinder to fill up with antifreeze. Or drive through some seriously deep water.

    In order for the engine to be “locked”, you’d have to have a sealed crankcase, and/or a cylinder that is completely sealed and gasoline fills the chamber completely AND there’s no way for the fuel to seep back out..... or be filled with water.

    It’s not a Diesel engine, so I totally doubt it was hydrolock
     
  11. Timbox

    Timbox Well-Known Member

    Messages:
    1,365
    Likes Received:
    389
    Trophy Points:
    83
    Location:
    Wisconsin, Tomah
    Tyler643,

    Could you post a pic of that crack you are talking about? As stated above, if these is a crack then something mush more damaging has happened to the engine. It could be all kinds of things and yes you will have to crack the engine open. If the crack is there and you don't have a donor block, why would you even crack open the engine? Time to look for a replacement if this is still something you want to do.
     
  12. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    I have a donor motor that is why I am pulling the motor.
    If that is the case how would all that fuel end up in the oil at the same time. And the number 2 cylinder that cracked be the same carb that was leaking?
     

    Attached Files:

  13. Timbox

    Timbox Well-Known Member

    Messages:
    1,365
    Likes Received:
    389
    Trophy Points:
    83
    Location:
    Wisconsin, Tomah
    The gas in the oil is a normal thing to happen when the float bowl jets don't stop the flow of gas. The petcock will leak letting gas through or it is left on prime. The gas then slowly leaks into the engine. The gas then runs down into the oil sump. As for that crack, there is a lot going on inside that gear/crank area. If you get a chance to pull it apart to see if a connecting rod let go or the transmission blew up? I don't know if the battery and starter on these motorcycle could brake a connection rod, wrist pin or anything connecting to the crank? Is it strong enough to try to push through a hydro lock, I don't know I guess anything is possible. Most hydro locks I have seen will not give visible damage to the outside. You have to pull the heads or even the jubs to see if something is broken or let loose. Normally you can hear it when you try to hand turn the motor. Looking down the cylinders to see if all the pistons are more moving.

    The crack in your case I am guessing is from either a engine full of water and froze or the trans or crank when when it was running. Wow....and good luck with the engine swap.
     
  14. Tyler643

    Tyler643 New Member

    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Roy Utah
    Hmm. Once I get it out I'll dig into it and let you know what I find. But I'm almost positive it's not water because it's always in my garage and it's been a long time sense I washed it or anything like that. I will let you know. Thanks
     

Share This Page