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Latest post Wed, Oct 12 2005 6:32 PM by RoyalBlue39UL. 5 replies.
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  • Mon, Oct 10 2005 8:02 PM

    4 speed mainshaft oil leak

    Has anyone used part #6200100? I bought one to stop the leak between the mainshaft and the main drive gear. Catalog says it fits 36-80 4 speeds, mines a '39 When I installed it, the clutch hub won't go back far enough to "seat" on the shaft, it is hitting the nut. Do I have to modify something or leave the oil deflector off? Thanks.
  • Mon, Oct 10 2005 9:36 PM In reply to

    • MadMick
    • Top 25 Contributor
    • Joined on Fri, Nov 29 2002
    • Rockbank Australia
    • Posts 2,312

    Re: 4 speed mainshaft oil leak

    This is from Hawg Ryder which covers your problem. ..Mick N. As far as the mainseal on the tranny, they typically don't last forever on the 4 speeds. Can't say the shop did anything wrong. It's hard to keep 'em leak free for long. But there are some things to look for. Number one, the seal actually "seals" against the sprocket spacer...if that spacer ain't mirror smooth where the seal lip rides, it should be replaced with the new seal. Also, I always put a little gasket sealer around the outer diameter of the new main seal before I put it in the case...helps keep anything from wicking around the edge. While you're in there, don't forget to replace the smaller seal that fits in the drive gear and seals against the actual mainshaft. And finally, I really recommend using a "DuoSeal" nut to hold on the sprocket. It's a special sprocket nut that has a seal built into it, adds a bit of redundancy and double seals against the sprocket and mainshaft. JP sells them, they're cheap, about $17 (I'd give ya' the catalog number, but I ain't at home right now). Replacing the seals is pretty basic, once you go through the pain in the ass of removing the inner primary. Remove the inner primary and take off the sprocket. You'll see the main seal easy enough. Pry it out...you may have to very carefully drill or punch a small hole through the steel body of the seal to get an awl in there to pry against (be careful, only go deep enough (about 1/8" max) to put a hole in it...there are some needle bearings behind it and you don't want to hit those) I have a small slide hammer I use for pulling it, but you can pry it, no sweat. Then pull the spacer and inspect it. When you put the new seal back in, coat the OD with gasket sealer, oil the seal lip a little, slip it over the spacer and carefully knock it in place (hint, you can set a short piece of 2" diameter pvc pipe against the seal body, then tap the other end of the pipe with a mallet to knock the seal in place until it's level with the case). For the smaller mainshaft seal in the drive gear, use an awl to pry it out. Same as with the mainseal, put a little sealer around it's OD, then seat it back in place using a short length of 1" diameter steel pipe...grind a little bevel on the outside edge of the steel pipe and it'll work perfectly. Don't forget to oil the lip of that seal too, before you slip it over the shaft. A seal installed fully dry can actually "burn" from friction and shorten the life of the seal greatly. When you put the sprocket back on, put a little silicone sealer (one of the only places I'll use silicone) on the backside of the sprocket, just a little thin bead around the splines in the hole where it seats against the spacer. This will help seal it tight to the spacer, preventing any seepage). Then bolt everything up. It's a good idea to replace the seal in the inner primary too. And check the bearing while you're in there. Then just button it all up.

     "When you're young you live to ride. When you're old ,,,,,you ride to live"

  • Tue, Oct 11 2005 6:00 PM In reply to

    Re: 4 speed mainshaft oil leak

    Thanks for the info, but it still dosen't tell me why the "duoseal" I bought dosen't seem to work on my bike. It's at least twice as thick as the stock sprocket nut, and it's keeping the clutch hub from going back far enough. I don't think I have the small seal that's described, at least I didn't see one and I can't seem to find mention of one in any of the manuals or parts catalogs I have. Hasn't anyone actually used one of these seal/nut?
  • Wed, Oct 12 2005 8:27 AM In reply to

    Re: 4 speed mainshaft oil leak

    the oem number for that small seal is 12013A, our number is 6200115. i've never installed a duo seal, but i know a lot of people who have, so it should work.


  • Wed, Oct 12 2005 8:31 AM In reply to

    Re: 4 speed mainshaft oil leak

    oh, and the reason you may not see it, is according to the parts manual, they didn't start using it until about 1965, but i think it's ok as a retro fit. oil control wasn't a big issue in 1939, only four years earlier, most of the harley's were a total loss engine oiling system which meant that after the oil went through the motor, it just ran out on the ground. when you filled it with gas, you filled it with oil also.


  • Wed, Oct 12 2005 6:32 PM In reply to

    Re: 4 speed mainshaft oil leak

    Thanks sfranta.
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