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UL Oil pressure issue

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  • UL Oil pressure issue

    I recently finished a 1941 UL build. I did not build the motor but the person that did build it is an experienced builder and built my 1952 FL with great results. The 41 UL has about 400 miles on it and I noticed oil leakage from the rear cylinder exhaust valve cover at about 100 miles, when I started running it a bit faster than initial break-in miles. When running the bike at 45-55 mph it throws oil on the transmission, rear exhaust, etc. (i.e. the leak is not merely a seep). At about 250 miles I checked the valve cover gaskets and since inspecting, adjusted valve clearance on all valves. I could not find anything wrong with the rear exhaust valve cover gaskets. I have a 48 UL that I have been riding/maintaining for 50+ years, so feel like I understand how the valve covers should "fit."

    It seems like the motor may have to much oil pressure in the gear case? I run a front drive belt, but have the front chain oiler vented to the ground. The builder reportedly installed a new "flutter valve" in the gear case cover. The oil feed pump is new old stock and appears in perfect condition. The scavenger pump seemed to be in great shape also. I checked the oil adjustment screw and it is 3/8" (0.375 in,) below the top of the pump body (per page 28 in my service manual).

    I then turned back the oil adjustment screw a full turn and the screw is about 0.335" below the top of the pump body. Upon test ride it seems like the valve cover might leak a bit less than before.
    I do not want to decrease oil pressure any further using the oil adjustment screw without a better understanding of how much oil pressure the motor is producing. Does anyone know where I can purchase an oil pressure gauge that I can connect to the existing oil pressure sending unit "port" on the motor? I don't think I should decrease the oil pressure until the oil light "flickers" as I am unsure of how good the aftermarket oil pressure sending unit works.

    Also, is it possible that the builder did not time the crankcase breather valve correctly (page 70 of my service manual)? If the breather valve is off just a small amount would the motor build up to much pressure in the gear case, resulting in leakage from the rearmost valve cover? (Aside: When I was a dumb ass kid (now only a dumb ass ole guy) I put together my 48 UL the first time without timing the crankcase breather. On it's first run from Sturgis to Deadwood, it left a large oil puddle under the bike at the Old Style (apparently the breather adjustment was way off). Rode it back to Sturgis and with advice from someone more experienced, pulled the gear case cover and timed the crankcase breather, which solved the big oil leakage issue.)

    Any feedback to the two questions I posed or other comments/advice would be greatly appreciated.

  • #2
    Put a thin layer of grease on your gaskets, one of your covers might be compromised.
    Carl
    http://www.carlscyclesupply.com

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    • #3
      You mention the one way valve in the cover, was it installed correctly? it must work only one direction, to allow oil from the breather cavity to be drawn back into the crankcase. And yes, breather timing is critical.
      Robbie Knight Amca #2736

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      • #4
        Most common breather mistake: timing the dot on the rotor with the slot in the pump tower to line up when the cam marks align.
        Many, many over the years say "that's what the manual says", but it doesn't. They can't be done at the same time.
        The Linkert Book

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        • #5
          Thank you for the input Carl, Robbie, and kitabel.

          Carl, the oil is leaking from the bottom of the rear exhaust valve cover; that is, from the bottom cork seal. Prior to build, covers were inspected and when I recently pulled the covers up to adjust valves the bottom surface of the valve cover that seats against the cork seal on the rear exhaust cover was carefully inspected again. Carl, it's hard for me to believe there is something wrong there. Also, I don't understand how grease will aid in sealing the cork/cover interface.

          Robbie, based on your comments, I think it best that I pull the gear case and check the flutter valve in the gear case cover (as explained on page 54 of my service manual). Also, I will then check the timing of the crankcase breather valve, at that time. Not to big a job; the worst part (as I'm sure you know) will be removing the gearcase gasket and cleaning the surface. I think the motor builder used adhesive on the gaskets. I can't remember, will I need to remove the oil feed pump before removing the gear case cover or can I just leave it on the cover? I guess it will become obvious as I proceed, but would be nice to know before I start. Also, I think I should re-set the adjusting screw on the oil feed pump back to the manual spec.; i.e. 3/8" below top of pump body.

          Kitabel if I understand your comment correctly, I get it; that is timing the crankcase breather is done independently and usually prior to timing the cam gears.

          Once again, thank y'all for your input. Any additional input (including an answer to my question regarding removing the oil pump independently of the gear case cover) is much appreciated.
          Greg

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