Seized Suzuki T500?

Discussion in '2 smokers' started by morini, Jan 7, 2020.

  1. morini

    morini Newbie

    Joined:
    Jun 3, 2013
    Oddometer:
    53
    Roads are icy, so I am trying to work on some of the forgotten projects in the back of the garage. First out is a 1971 Suzuki T500 that only ran on one cylinder when I bought it five years ago.
    FB26C006-65C3-4581-AB81-5B14C4DB799E_1_105_c.jpeg
    New points fixed the running issue and it ran fine for five minutes before I turned it off. When trying to restart it the engine would not turn over. This is what I did:
    1: Removed the crank drain plugs in case it was flooded.
    2: Removed the spark plugs to get compression out of the equation.
    3: Put some oil in the cylinders, just in case, and let it stand over night.
    4: Put it in fifth gear and tried to move the back wheel.

    All to no avail.

    My first thought was that it had been standing for too long so that the cylinders had insufficient lubrication (even if I had put extra oil in the petrol) and hoped it was only a minor seizure which could be fixed with honing and new piston rings. Next steps:
    5: Pulled the heads to check the liners. Saw that the pistons moved ca 1cm up/down when turning the back wheel (in fifth).
    6. Pulled the cylinders which confirmed that the pistons where not seized.
    7: Had a long depressing look at the non moving crankshaft and
    8: poured myself a double whisky.

    This is how far I have gotten in my limited garage time. I know that the crank sealings can dry out when these bikes are not run for long periods, so I have kicked it over regularly. And if that was the problem the crank would not seize, but leak, right?

    I am afraid I am facing bearing failure which probably is out of my league, or am I missing a possible easy solution?

    Best regards from icy Norway!

    Attached Files:

    #1
  2. dlearl476

    dlearl476 Two-bit Throttle Bum Supporter

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    Fill the case with ATF. Let it sit for a couple of days. Drain it. Try to turn it over again.
    #2
  3. bark sampler

    bark sampler Been here awhile

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    Don’t get discouraged, it could be something simpler. I’ve had magnets come off flywheels as the adhesive gets old and lock up on the coils. Not a Suzuki or a Titan, but worth popping the side cover.

    Did the Titans have oil injection to the crank bearings? If so, it is less likely to be in the crank.

    Edit: And nice looking bike!
    #3
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  4. KennyV

    KennyV Been here awhile

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    Hopefully it's nothing major. That's a very nice bike, one that's on my wish list.
    #4
  5. Spikester300

    Spikester300 Roll Tide!

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    Check clutch and kick starter gear in case something jamming up the works.
    #5
  6. morini

    morini Newbie

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    Thank you for the moral support! Luckily it seems that it is neither the crank nor the gearbox: When I removed the stator on the left side I found a bent piece of metal between two of the magnets on the rotor. I managed to get it out, but it has done some damage to the stator. I will probably need a new stator, but I guess this should be up and running shortly.

    What bothers me is where this metal part came from, how it got there and if it had an important job anywhere else. I cannot find any place where a part i missing. Does any of you recognize this bent part? View attachment 2074795 View attachment 2074797 View attachment 2074798
    #6
  7. morini

    morini Newbie

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    EAA303DC-61FA-4662-B9C8-E18496848EC9.jpeg 3B905990-8DF3-40DC-AF08-B9B975C5F780.jpeg 4180B3CA-F9BF-4218-A498-61FE95DEA735.jpeg
    #7
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  8. bisbee

    bisbee n00b

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    Bisbee AZ.
    I am in the process of going through a gt500 right now, that looks like the lock washer for the nut that holds the rotor on.
    #8
    bark sampler likes this.
  9. Spikester300

    Spikester300 Roll Tide!

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    Oh, that's where it went.
    #9
  10. morini

    morini Newbie

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    @bisbee: Of course. Thank you. I should have thought of that. Now I just have to source a new one and have peace of mind. Do you have the dimensions for this? I guess finding an original part will be challenging.

    On second thought: Normally a lock washer presses against a normal/flat washer, but I can not find anything else rummaging around in there. Is it only nut, lock washer and rotor or am I to expect more entertainment when more washers find their way to the moving bits?

    Very pleased that the crank seems OK:-)
    #10
  11. bisbee

    bisbee n00b

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    My bike did not have a flat washer although the parts book shows one. I can check the size when I get home. A good place for information is the sundial motorsports website, all two stroke Suzuki's. the washer is 12mm id.
    #11
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  12. MK1MOD0

    MK1MOD0 Been here awhile

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    Nice that ya found the issue. I was thinking..... of all the old two stokes with bad cranks I’ve seen, I’ve never seen one completely locked. They would usually move ( with reluctance) when rocked back and forth. Check with Ricky Stator and see if they could rebuild that for you. May be easier than finding a NOS unit.
    #12
  13. baloneyskin daddy

    baloneyskin daddy bikaholic Super Supporter

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    At 1st glance the bike looked very clean but I notice some welding on the cases in your 1 picture. Looks like maybe a chain broke and bound up in the cases causing the break. It also could have caused an instantaneous engine stoppage and the weight of the rotor caused it to spin on the end of the crankshaft and loosen the bolt holding it on ,causing it to slowly over time back out . I'd examine the engine a little deeper before starting to fix things.Pull the rotor and make sure the crank end isn't damaged. Check for damage around the fr sprocket and countershaft.
    #13
  14. morini

    morini Newbie

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    Yes, it has definitely had a broken chain in its time and was priced accordingly. Your theory about the effect of the instantaneous engine stoppage seems plausible. I´ll check everything before reassembly. Eager to hear the ring-ding-ding again and breathe in burnt 2 stroke oil again. It is still the smell of freedom to me, probably due to my endless illegal adventures on a Zündapp GTS50 at the age of 14:-)
    #14
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  15. baloneyskin daddy

    baloneyskin daddy bikaholic Super Supporter

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    I grew up on Kawasaki triples and still have one but it hasn't been run in a lifetime.
    #15
  16. TNWillie

    TNWillie Long timer

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    I thought I'd add to this thread vs starting my own because it has to do with a seized top end that I'd like suggestions on freeing up.
    In my case, its a GT750 that sat in my garage too long. I am 99% certain that the piston(s) are stuck due to rust. I have tried squirting a helluva lot of thread penetrant in each plug hole and let it set/soak for days before pushing down on the piston crown using a wooden dowel. Nothing! Still locked up solid. Having read through this thread, I like the idea of filling the cylinders up with ATV and letting it soak awhile. Any other suggestions out there? I was considering heat but in light of the block being liquid cooled, the only way that comes to mind is to remove the thermostat and try and pour boiling water in there. I doubt that's very feasible though.
    Also, fwiw, here's a pic of it. Buffalo Rt side.jpg
    #16
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  17. aptbldr

    aptbldr easy rider

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    Have rear wheel stand? If so consider selecting high gear and 'bumping' the engine by hand, rotating back wheel.
    Be careful (no sparks); when it does start moving whatever you've used as penetrant-lube could be splashing back out the plug opening(s)
    #17
  18. TNWillie

    TNWillie Long timer

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    I don't have a rear wheel stand but I have tried bumping the engine by hand in high gear. Thanks.
    #18
  19. snarlyjohn

    snarlyjohn Human money repellant

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    Australia
    Nice bike. The top end is gonna have to come off anyway for a freshen up, so remove the head and make or adapt a puller (something like a harmonic balancer puller works well) that attaches to the head bolt holes and use this to push the pistons out. Use a small plate under the screw to avoid pushing a hole through the piston crown. It'll be the quickest way to get it up and running again.
    #19
  20. morini

    morini Newbie

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    The roads have been dry for weeks, so I have been riding instead of working in the garage and the poor T500 has been neglected. But now I am back. Problem is that I do not think there is any need for the new lock washer and nut I bought. It is difficult to find technical drawings of the T500, but it seems it is different from @bisbee GT500. I have now found a drawing and I cannot fathom where this lock washer goes:
    177F1BF3-9340-4B9B-B854-F2A7BD3CDD18_4_5005_c.jpeg
    I have the screw 22 and the smaller washer 21. The rotor on the T500 seems to be pressed to the crankshaft and I cannot see any big washer or nut on any drawings or in this bush-engineering disassembly video (5:40):

    Fitting everything as shown on the drawing works fine when the engine is turned by hand, but I have not dared to start it yet in case I am missing something serious. Any ideas?
    #20