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Ring problem?

Discussion in 'Motorcycle Tech Talk' started by Tommyc, Nov 28, 2011.

  1. Tommyc

    Tommyc Active Member

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    Hi fellers, I just got my top end put back together after buying new heads. I put on new rings and honed the jugs.
    The bike runs good but I'm getting some puffs of white smoke out the pipes and some oil leaking from the exhaust ports where the pipes attachs.
    The ring gaps were a little larger than specified could that be the problem?
    The gaps in the compression rings were supposed to be about 0.025 but they spec'd at about 0.032. Would this cause oil to seep thru and burn causing the white smoke or could it be the valve seals or head gaskets?
    Thanks,
    TC
  2. Fatboy128

    Fatboy128 Well-Known Member

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    Well from an automotive background, rule of thumb is: "If you see the oil burn it's valve seals" but that is not carved in stone. Rings SHOULD BE 0.025 however. I wouldn't have assembled it any other way. Again, from the automotive experience.
  3. hotroadking

    hotroadking Super Moderator Staff Member

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    Might be a valve seal/guide letting oil past
    pull the exhaust and look at the valves

    Also pull the pushrods and do a leakdown test
    that will let you know if it's getting past the rings
    as the valves will be closed.
  4. baggerpaul

    baggerpaul Well-Known Member

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    were is the cylinder heads breathing are they vented out of the air cleaner on that shovel? or under the bike on a hose and breather ? .025 to .32 . that is the ring gap before you torque the cylinders down on the studs they tighten down quite a bit . when they are torqued . and how many hot soaks have you done since you started it from the re fresh . on the top end ? maybe your rings did not seat yet . are you braking that motor in with real heavy oil ? all of these things come in to mind ? brother sorry to shoot all these questions at ya tommy!
  5. hotroadking

    hotroadking Super Moderator Staff Member

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    BP thats a good point
  6. Tommyc

    Tommyc Active Member

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    BP, It's vented out the crank case thru a breather tube. about 10 hot soaks. yes heavy oil, 70 wt.
    The motor is running great just some light smoke puffs from the rear exhaust pipe and oil leaking from the front exhaust port.
    I only have about 60 miles on the bike since refresh.
  7. baggerpaul

    baggerpaul Well-Known Member

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    ride that thing with 70 it takes quite a bit of time to seat the rings get it on 95 and bring the rpm up then let it slow down slow on its own a few times thats good for ring seal dont keep it at a same rpm for long periods of time .! then if it dont clear up check the valve seals on front cylinder some times machine shops forget to put the seals in or dont run seals on the intake side at all does the plug on the front cylinder have oil spots on it ?
  8. Tommyc

    Tommyc Active Member

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    I will check the plugs soon. Thanks for the info.
    Is it a common thing for an HD shovel motor to leak oil as it's being broken in?
    It doesn't seem right to me.
    Would leaking head gaskets cause oil to burn out the pipes and leak around exhaust ports?
  9. baggerpaul

    baggerpaul Well-Known Member

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    it depends on the finish of the bore and how well the rings seal is at start up . and infact if the valve seals are installed proper or installed at all ? they are put together by man and any one can make a mistake and forget to install one ! no biggie if thats the fact pull the plug and just take a compression gauge hose pull the sharder valve out of the hose connection . and hook it up to compressed air remove spring replace or install a new seal . and put it back together.valve seal job done! as far as the head gaskets i think it would be more of crancase pressure in the oil tank building up and pushing oil out of it . not sure on that answer but i doubt its a head gasket seal problem it would not be running well . and down quite a bit on compression
  10. Tommyc

    Tommyc Active Member

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    I pretty sure the valve seals are there and I don't think it's possible to pull the rocker box cover without pulling the heads on a shovel.
  11. baggerpaul

    baggerpaul Well-Known Member

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  12. Tommyc

    Tommyc Active Member

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  13. baggerpaul

    baggerpaul Well-Known Member

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    only you would know how big those returns were tommy sorry to say that for that i dont have an answer for ? the only way i would think to check is to start and run it while it is warm take the boxes off and if one head pours out oil and the other is not the return on that cylinder is not flowing enough. but put some temp in the motor and a few more miles on it . maybe its just ring seal thats all . you staggerd them correct? and you did not happen to break one by mistake? cylinders went together fairly easy?
  14. Tommyc

    Tommyc Active Member

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    Yes I staggered, no didn't break one. went together fine. I put a scratch on the rear piston skirt with the ring compressor, would that make it smoke?
  15. baggerpaul

    baggerpaul Well-Known Member

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    it would have to be a real deep scratch and gaul the cylinder wall to keep the rings from seating . so i doubt it .and you would have alot of blow by out of the breather area!it would huff like a bastard
  16. Tommyc

    Tommyc Active Member

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    What about leaking head gaskets would that cause it to smoke and leak?
  17. baggerpaul

    baggerpaul Well-Known Member

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    maybe but i doubt it. it would be low on power and compression!!
  18. hotroadking

    hotroadking Super Moderator Staff Member

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    might want to go to a lighter weight oil for break in, HD360 50wt, like he said eariler
    running 70 might be slowing the seating down...

    No wait it's synthetic that does that LOL

    Pull the front exhaust header, inspect the valve, if the seal is not there
    or it's leaking you'll see oil running down the valve, if it's clean then the seal
    isn't the problem, do the same with the intake, pull the carb and intake and
    visually inspect the valve stem. Better than pulling the top off the engine again.

    At least if you find oil on the valves or a lot of oil on one you know you have to go
    in to fix the seal...
  19. Tommyc

    Tommyc Active Member

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    I did that when I put new pipes on last week and I did see some oil on the valves stems.
    Would that cause oil to come out the exhaust port?
  20. baggerpaul

    baggerpaul Well-Known Member

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    yep!

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