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  1. #1

    Xl 1200 Low Compression Rebuild

    I have dismantled my "new" xl1200 to fix the 3rd cylinder low compression. Originally, I wanted to install the oil block off plate, but figured I would fix the cylinder while I had it in pieces.


    Background:
    Compression was 112-113-96
    Ran fine but I wanted to install the block off plate


    Anyway, it is all torn down, and the cylinder is visibly scorn, a couple of the scores can be felt.
    The head looks fine, but the 3rd cylinder was not as wet as the others. I'm guessing this was just lack of oil?
    Anyway, I will send the cylinder in to get re nicomed.
    In the mean time, are the pistons re useable? There is no visible damage to it.


    I also will order the appropriate non reusable gaskets.


    I wills post pics tonight, but I wanted to get opinions on reusing the piston in the mean time.
    Also, I can see the crank. Does this need to be filled to a higher level? With what?






    Thanks!


  2. #2

    Join Date
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    Howdy......I just rebuilt my waveraider 760 engine.....first rebuild I have attempted of a ski engine. I had the same problem you had....scored piston and cylinder wall. A machine shop can measure your pistons and tell if you can reuse them, but I wouldnt reuse the #3 piston. It has gotten hot, and when it scores it "smears" the surface of the piston. As far as replacing all pistons, there is a difference of opinion...can you bore one cylinder, or do you bore all and maintain balance? Depends if you are on a budget, but I bored both cylinders on my 64x engine. BTW, engine failed due to lack of oil...previous owner used the injection system. When the shop hones out the good cylinders, be sure piston to cylinder clearance can be maintained within manufacturer's specs, if it can, you can rering the two good ones, and it is a perfectly acceptable repair, and will give satisfactory performance. As a side note.....after the rebuild, I personally recommend a premix of 32:1 for a couple of tanks, and very little WOT operation, and varied throttle operation, for a proper break in period. After that...check your compression, all plugs out, and throttle wide open, to establish your baseline compression, which is useful in maintenance and diagnosis later on. BTW pressure differential is MUCH more important than individual cylinder pressure. A differential of 10% is usually acceptable.

  3. #3
    Quote Originally Posted by butterbean_29512 View Post
    Howdy......I just rebuilt my waveraider 760 engine.....first rebuild I have attempted of a ski engine. I had the same problem you had....scored piston and cylinder wall. A machine shop can measure your pistons and tell if you can reuse them, but I wouldnt reuse the #3 piston. It has gotten hot, and when it scores it "smears" the surface of the piston. As far as replacing all pistons, there is a difference of opinion...can you bore one cylinder, or do you bore all and maintain balance? Depends if you are on a budget, but I bored both cylinders on my 64x engine. BTW, engine failed due to lack of oil...previous owner used the injection system. When the shop hones out the good cylinders, be sure piston to cylinder clearance can be maintained within manufacturer's specs, if it can, you can rering the two good ones, and it is a perfectly acceptable repair, and will give satisfactory performance. As a side note.....after the rebuild, I personally recommend a premix of 32:1 for a couple of tanks, and very little WOT operation, and varied throttle operation, for a proper break in period. After that...check your compression, all plugs out, and throttle wide open, to establish your baseline compression, which is useful in maintenance and diagnosis later on. BTW pressure differential is MUCH more important than individual cylinder pressure. A differential of 10% is usually acceptable.

    Well, I am watching what I spend on it, because I would hate for it to turn into a money pit. So is it best to go ahead and nikasil the cylinders or try a hone?

    Below are cylinder pics and piston pics.
    Can the piston be reused?
    What is the diagnosis on the cylinder?
    And are the pv supposed to have that much gunk?

    Thanks For the reply!!!
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  4. #4
    The power valves do get pretty gunked up, especially depending on the oil you use. That power valve isn't that bad (at least from what I can see in the pic). Nice to see the waveater clip on it though.

    The cylinder and piston pics are harder to see. The closeup cylinder pic does look pretty bad... I don't think I'd use it like that and would probably send it to get re-nikasiled... I'm not a fan of sleeves.

  5. #5
    Quote Originally Posted by kmc View Post
    The power valves do get pretty gunked up, especially depending on the oil you use. That power valve isn't that bad (at least from what I can see in the pic). Nice to see the waveater clip on it though.

    The cylinder and piston pics are harder to see. The closeup cylinder pic does look pretty bad... I don't think I'd use it like that and would probably send it to get re-nikasiled... I'm not a fan of sleeves.

    So it already has wave eaters on it? The previous owner never told me he put those on. Good to know, given that I was getting ready to order them.

    Anywho, I will take better pics today, I just wanted to get some ideas about the condition, so I took those with a flashlight. Lol

    thanks for the help!!

  6. #6

    Join Date
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    Quote Originally Posted by tejhummer View Post
    I have dismantled my "new" xl1200 to fix the 3rd cylinder low compression. Originally, I wanted to install the oil block off plate, but figured I would fix the cylinder while I had it in pieces.


    Background:
    Compression was 112-113-96
    Ran fine but I wanted to install the block off plate


    Anyway, it is all torn down, and the cylinder is visibly scorn, a couple of the scores can be felt.
    The head looks fine, but the 3rd cylinder was not as wet as the others. I'm guessing this was just lack of oil?
    Anyway, I will send the cylinder in to get re nicomed.
    In the mean time, are the pistons re useable? There is no visible damage to it.


    I also will order the appropriate non reusable gaskets.


    I wills post pics tonight, but I wanted to get opinions on reusing the piston in the mean time.
    Also, I can see the crank. Does this need to be filled to a higher level? With what?
    Thanks!
    There are a few things to consider:

    The most important thing to figure out is what EXACTLY caused your problem. Was it really a lack of oil? Did the oil line plug or come loose? Is your carburator running lean? Do you have a dirty internal filter? Do you have a leaking crank seal (this would also cause you to run lean)? Older engines do develope these problems with time.

    If you do not find what caused your problem, you may get the same results after you rebuild.

    Pistons are reusable if they are within spec. I would get a new piston, bearing, piston pin, and re-ring it. Clearly, your piston and associated parts would be the weak link in your engine if you did not replace them.

    You can you use something like muratic acid to remove the aluminum that is stuck on to the nicasi cylinder wall. Hone it and then check the cylinder to make sure that it is within specs with no SERIOUS groves cut into it. If it does have groves, then re-nickasil it. I would think that since your compression was not really good, but not completely gone that the cylinder has a good chance of being saved. It is good that you caught your problem early.

    Check your power valve and make sure that there is no damage. They need to be cleaned from time to time on a routine basis.

    Check inside the crank case looking at the crank for any discoloration to the crank bearings. Remember that this part of the engine has been subjected to high heat, lack of lubrication, or both.

    Your crankcase should not have any significant level of oil in it. Remember that the bearings get their lubrication from the oil/fuel mixture that enters from the carb, not from an oil sump. High winds from the crank turning is what spreads the oil to the bearings. It would not hurt to put a few cc's of oil directly on your bearings for start up though.

    Good luck.

  7. #7
    If anything, I think Its running rich. Plugs all showed this to be true. I think since I can physically feel some of the cylinder scoring, this may have been my problem.
    No Oil Lines were off, although the head and cylinder on number 3 were not as wet as the others.
    Im not sure what an internal filter is, but thats probably good to know.

    There is a good bit of oil in the crank case, So I don't know what to think about that.

    Thanks for the help!

    Tom

  8. #8
    Quote Originally Posted by salty View Post
    Quote Originally Posted by tejhummer View Post
    I have dismantled my "new" xl1200 to fix the 3rd cylinder low compression. Originally, I wanted to install the oil block off plate, but figured I would fix the cylinder while I had it in pieces.


    Background:
    Compression was 112-113-96
    Ran fine but I wanted to install the block off plate


    Anyway, it is all torn down, and the cylinder is visibly scorn, a couple of the scores can be felt.
    The head looks fine, but the 3rd cylinder was not as wet as the others. I'm guessing this was just lack of oil?
    Anyway, I will send the cylinder in to get re nicomed.
    In the mean time, are the pistons re useable? There is no visible damage to it.


    I also will order the appropriate non reusable gaskets.


    I wills post pics tonight, but I wanted to get opinions on reusing the piston in the mean time.
    Also, I can see the crank. Does this need to be filled to a higher level? With what?
    Thanks!

    You can you use something like muratic acid to remove the aluminum that is stuck on to the nicasi cylinder wall. Hone it and then check the cylinder to make sure that it is within specs with no SERIOUS groves cut into it. If it does have groves, then re-nickasil it. I would think that since your compression was not really good, but not completely gone that the cylinder has a good chance of being saved. It is good that you caught your problem early.

    What do I hone with? Ball hone?
    What is spec on the 1200?

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