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Thread: Knucklehead oil problem found, solution unknown...HELP

  1. Knucklehead oil problem found, solution unknown...HELP

    This email was for Sarge but after attempting to send it, he has no room until he deletes something. So here I go trying to start a thread and having no clue how to do so. I have a 41FL, new to me and bought in pieces. I got it all together and running, but had no oil returning into the tank. After talkin* to sarge for a minute, he suggested a service manual and spare parts catalog which I have now(awesome tools) and ventured a little deeper and found the problem but a lot unsure where to go from here. Thanks for any help!


    Thanks for the reply and the info. After your reply I was able to obtain a service manual and a spare parts manual. Some very good info in there. The diagrams are very detailed and very useful. I have some parts ordered now and I have a lot more questions since disassembly. Sorry. Lol.

    What I found is all of the gears from inside the case through the oil pump shaft and to the outer two gears, all is well. Very minor play between the inner gear and shaft, possibly a worn key way. I have a new shaft kit with all new keys, shaft, retaining clips, and inside oil pump gear. This isnít going to fix anything though. The very unique problem I have found is the oil pump pinion shaft gear(spiral gear)(686-39) is destroyed. Along with that, the gear shaft bearing oil seal ring(356-40A) is smashed and mushroomed into the case. The oil pump drive shaft gear(623-39) is chewed up a little but as I said I have that ordered.

    The solution? I canít find anyone who has ever seen this before nor can I wrap my head around what would make this happen. So again I come to you with questions. Iím not sure how the gear shaft bearing oil seal ring(356-40A) is removed. Is it pressed onto the shaft? It is definitely stuck and not sliding but I havenít tried too hard yet because Iím not sure how it is supposed to come off. What could possibly make that spiral gear push into that oil seal so hard that it would mushroom that seal out and get it stuck? How could that gear get so chewed up? I feel like the chewed up gear is the biggest problem here however, did the chewed up gear deform the seal or did the seal being mushroomed out and pushed back allow the gear to ride too far back on the shaft and consequently tore up all of the teeth on that gear?

    I have some friends that all assumed the inner gear had sheared a key and they had seen it happen many times but since I have found these issues and determined itís not a sheared key, everyone is lost. The only person I could have asked passed away recently and he had more knowledge of these bikes in his little finger than I will ever have. He owned the dealership here in Dayton for many many years and he was the most knowledgeable Harley guy around. I think he would have enjoyed this situation. He took pride in fixing what everyone else thought they could.

    So again, I come to you, asking for advice. Thanks again for your help and I look forward to hearing from you. Iím going to try to send some pics too but not sure if I can on here.


  2. Re: Knucklehead oil problem found, solution unknown...HELP

    I tried to post pics from the iPad but it won’t let me. Says they are too large. I’ll try to figure out how to make them smaller but would be happy to email them to anyone. A picture is worth 1000 words right? Thanks again.

  3. #3
    Join Date
    Mar 2008
    Beautiful Northern NM

    Re: Knucklehead oil problem found, solution unknown...HELP

    Was the pinion gear a press fit and if so was it the proper distance from the face of the case? If pressed in too far the spiral gear will be under pressure to the seal ring and also not line up with the oil pump drive gear. which can destroy them both. Did you check things as they were removed?
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  4. Re: Knucklehead oil problem found, solution unknown...HELP

    It was not pressed. It slid right off as I rotated the oil pump gear. It seems like it is just floating on the shaft. It is definitely back too far. I’m just not sure what came first, the seal allowing the spiral gear to go back too far or the gear pushing the seal back too far. The inside of the spiral gear is chewed up along with the front side of the seal.

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