Online: Hilly, speedzter, softfat

oil migration

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  • GGUser744
    GGUser744
    1 month
    rollies replaced primary seals a couple years ago not sure if main crank seal was done ,i replaced that seal 3000 km ago, looking at the old sleeve/race the marks where the seal sat they look even not sure if the seal is oe just stabbing in dark,

  • GGUser744
    GGUser744
    1 month
    found the problem, put dye in engine went for a 85km ride after couple days didn't think gone far enough but checked anyway dye in all three compartments ,checked crank runout at compensator outer edge .016 thou (.4mm) checked  lock nut washer the same, marked the spots runout in the same spot.i know some will say check at crank but to far out to go any further if it was close id go further. I believe this all stems from head on  accident 11000 km ago complete front end replacement, have reopened insurance claim waiting for assor to visit
  • GGUser744
    GGUser744
    22 days ago
    well insurance says wear and tear looks like I'm going to rebuild the old girl i have a pinion shaft runout tool on the way ill check properly to see how much the shaft is actually out and decide weather to replace or repair flywheel assembly , seems the only ones available are s&s looking at 3 grand i cannot find a cheaper brand than that,why cheaper you say 1 budget tight ,2 im not a boy racer give it a bit of stick occasionally and do mostly touring im 69 done 85000 km so i think ill be doing well to do another 85000 on her  ,anyone out here got a take out flywheel sitting around let me know,surely there was a lot of upgrades from when these bikes were new if anyone interested ill keep you posted
  • Hilly
    Hilly
    22 days ago
    I've seen take out engines for sale for less than the S&S crank, obviously they are an unknown. 
    Just a heads up, S&S have updated their crank, the pin is now welded like Darkhorse and other rebuild mobs do, so if you do go that way get the latest one.
    Other option you could look at is getting yours rebuilt here in Australia, can't remember off the top of my head who does it but I've heard it mentioned.
  • GGUser744
    GGUser744
    22 days ago
    i know someone who used to do flywheel straitening in their workshop and still has the gear we are going to have a crack at it and see how it turns out 
  • GGUser744
    GGUser744
    16 days ago
    bought a dial indicator 2 thou runout on pinion shaft is this ok or straighten fly wheel needed

  • Hilly
    Hilly
    16 days ago
    .002" is pretty good, think the " Harley " allowable limit is. 012", that's way too much, I wouldn't pull it in half for 2 thou. 
  • GGUser744
    GGUser744
    16 days ago
    when it was flywheel i at least had a direction, now not sure,ill strip the primary and see what i find

  • Hilly
    Hilly
    16 days ago
    Trying to think this through, the dye went from engine to primary to gearbox, you are positive of that, taking that as yes. 
    Crankcase pressure must be forcing engine oil through, it's odd because you said at one point the primary was low and the excess in the gearbox refilled the primary to the correct level.
    Assuming that is correct then the oil migration out of the engine and into the primary must be minor but enough for dye to travel or you would have more engine oil in the primary.
    The pressure could be building up in the primary and forcing the primary oil through the main shaft along the clutch pushrod into the gearbox, that's the only path I can think of, it's only going to be the oil that's thrown up that can be pushed as the shaft isn't submerged is it?
    You said it's always used a bit of engine oil, maybe the rings are worn or broken, cylinders scored or out of round causing excessive crankcase pressure and some oil burn? 
    You replaced the crank main seal you said, you think it was done previously as well, sort of throws shade on the seal itself being the problem.
    I'd check for excessive crankcase pressure, make certain your breathers are breathing as they should, then check for blow by in the crankcase by compression and leak down tests before you pull it apart. 
    If that fails to shed light on anything then maybe you do have a cracked case and the crankcase pressure is just following the path of least resistance?
    Anyone else got any ideas? Happy to be corrected in any of this thinking.

     
  • GGUser744
    GGUser744
    16 days ago
    (it's odd because you said at one point the primary was low and the excess in the gearbox refilled the primary to the correct level.)this bit here oil migrated to gearbox primary found low of oil no external leaks after dealership service geabox not checked at this time not thinking migration problem  all oils changed and refilled road bike 3000 km rechecked at this time checked all levels geabox up primary down, readjust levels dye put in engine, my next move dismantle primary and check main seal
  • Stuart
    Stuart
    16 days ago
    How much oil is migrating? It sounds like a bit if an 85k ride pushes enough oil from the engine through to the gearbox and you can see dye in the gearbox.

    Is the engine oil noticeably down?

    An earlier post said the primary was almost empty. If I overfill my 2005 Dyna gearbox by 100ml or so, the excess comes out of the gearbox breather - and is quite noticeable after a run. If the primary is almost empty, there must be at least 500ml gone somewhere - I don't think that much extra will fit into a correctly filled gearbox.

    I'd be draining all oil compartments and measuring what goes into each of them when they are refilled. Then measuring what comes out of each one after a decent run or two.

    I bought a rough old 4 speed years ago and went through similar issues. I was convinced that the gearbox oil was migrating to the primary. Turned out that the crank seal was shot, which was letting engine oil into the primary. *And* the piggyback plug in the stripped out gearbox drain was leaking. Which was draining the gearbox. Given the amount of oil involved, I had figured that I would see oil all over the back of the bike if the gearbox was leaking to that degree - there was a few drops on the floor from time to time was all.



  • GGUser744
    GGUser744
    15 days ago
    after 85 km no noticeable difference in levels but dye in all compartments, definitely 200 ml short in primary and 200 ml over in gearbox after 3000 km stuff all on engine down that i recall .new breathers in top, all breather passages clear including gearbox breather, no external leaks,im suspecting compensator spring wear a result of low oil,im led to believe that the seal behind clutch can assist with migration from primary to gearbox. im hoping when i dismantle primary tomorrow i might see a path with dye.
    question, when turning engine over plugs out cam chest dismantled rockers and pushrods out etc it still feels like compression and unable to turn engine smoothly is this normal i have been told it should spin freely as if compression holding it up the needle on dial indicator moves jittery not smoothely not sure if thats normal 

  • Hilly
    Hilly
    15 days ago
    No it's not normal
  • GGUser744
    GGUser744
    15 days ago
    so maybe bearing tight in spots

  • speedzter
    speedzter
    15 days ago
    The stator and rotor (magnets ) can cause an unusual feel if rotating by hand .
    Hard to call without having hands on to feel it.
  • GGUser744
    GGUser744
    15 days ago
    there is a slight tight spot on primary chain i have a auto tensioner think on re install will go back to manual that could play a part in tight spot as well ,i gotta dismantle primary anyway so no need to panic just yet until apart currently looking at .003 runout on pinion shaft,just so i got this right, when cam chest empty, primary striped crankshaft should spin freely ?,i have to wait until tuesday i cannot crack compesator nut and need to borrow rattle gun from someone who ows me a favor
  • John.R
    John.R
    15 days ago
    You have piston and barrels on this motor right?

    The friction from those alone will stop it from ''moving freely" 

    It will move, but will still require force to overcome that. 
  • GGUser744
    GGUser744
    15 days ago
    thanks for that tip i was thinking along those lines
  • Hilly
    Hilly
    14 days ago
    Quoting John.R on 25 Jan 2026 12:12 AM

    You have piston and barrels on this motor right?

    The friction from those alone will stop it from ''moving freely" 

    It will move, but will still require force to overcome that. 

    Resistance yeah but jittery na
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