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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.
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.
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