Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties UL feed pump

UL feed pump

Moderators: Curt!, Pa

Post Sat Jan 24, 2009 11:29 pm

Posts: 17
Location: Marcy,N.Y. USA
Hi. anyone know where i can purchase new oil pump vanes for UL feed pump, Part # 688-37= 26248-37 Would like N.O.S. I have had no luck with my searches. :( Also, anyone know any useful mods or info to increase volumn and or oil pressure on these vane type pumps :?: Thanks, Ben

Post Sun Jan 25, 2009 3:29 am

Posts: 575
Location: devon,england
hi ben 45parts depot has them in stock.
try this link ... y_id=11753

regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years

Post Sun Jan 25, 2009 4:00 am

Posts: 90
Location: Norway
look at this topic, it might be useful reading:

Post Wed Feb 04, 2009 12:52 am

Posts: 17
Location: Marcy,N.Y. USA
Thanks Jib fo info. :D Vanes on the way. Very sorry about Jims health problems, :cry: would have liked to have bought his book.Hope everthing works out for him.Got no response on mods to UL feedpump, spent 3 or 4 hours revuing all the posts i could find re. sidevalve feedpump. I will just go ahead with my own mods,am confident that with welding,machine work and longer vanes and pump chamber i will achieve at least a 1/3 more volumn and coresponding pressure so as to make optimun use of full flo and also add. oil to pistons and cyl walls. :roll: (New vanes will go in my spare) PS Anyone,i keep seeing referance to a registered owners list on some of the posts?? :?: I own a 37 UL and a 40 Knuck . How can i find out if i am on list or how could i get on list?? :?: Both bikes are registered.

Post Wed Feb 04, 2009 8:30 am

Posts: 1642
Location: Interlaken, NY USA

Urganb , Not trying to steal Jim's thunder here, but I'll give you the essence of his experimentations/modifications. First, you're on the right track, the feed pump doesn't move enough oil in stock form. Jim discovered that flow from the pump itself is hindered in the stock design and oil line layout. He took steps to prevent cavitation at the pump rotor and allow more oil to actually get to the rotor/vanes. He also developed a way to actually get skirt oilers to squirt oil in a useful quantity at the cylinders.
Although my efforts in improving oiling took a different turn than Jim's, I think his approach is probably a more useful one for many owners in that it leaves the motors looking basically stock, but give improved performance. With the stock rotors/vanes he achieved impressive improvements in volume and pressure. Just some things to keep in mind as you approach this project. We all root for you, yours may be the best ideas yet. There's a real problem that needs attention.
Marcy's not that far from Interlaken, I'm up that way (Utica) for work from time to time.. Small World.

Post Thu Mar 26, 2009 10:46 pm

Posts: 74
Location: Wichita, KS
Paul at American Cycle Fabrication has a conversion he does. Without knowing all the technical, he cross cuts the barrel 90* and installs a second set of vanes. He also has developed an internal oil spray system to wash down the pistons, etc. don't remember the gains he said he got on oil psi and flow.

Post Mon Mar 30, 2009 10:22 pm

Posts: 18
I've looked at the Sportster oil pump conversion, but if I can modify my stock oil pump to Jim's specs it might be a lot less work and lower cost. Did anyone get a copy of his book before he got sick, or was it still in the draft stages? Before his website went down it said "modified stock pump" in his flow comparisons. I hate to reinvent the wheel. Could someone PM me with Jim's number.

Post Tue Mar 31, 2009 4:19 pm

Posts: 49
Have you tried Lonnie at Antique Cycle Supply?, he was selling teflon replacement vanes a few years back. I installed a set of them in a feed pump rebuild I was doing at the time and never gave it any thought until this topic came up. I guess they're doing ok, the engine now has a bunch of miles on it and it hasn't blown up.


Post Tue Mar 31, 2009 5:37 pm

Posts: 18
Thanks, I'll contact him about the vanes. I wonder what Jim's internal modifications were. I suppose I can figure it out.

Post Wed Apr 01, 2009 8:08 am

Posts: 1642
Location: Interlaken, NY USA

Dukey, send me an email: Maybe I can help.

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