R51/3 front fork

[Bluebmw52]

Working on blue bmw 52 R51/3 front telescopic forks. Overhauled both with new tubes , new dampers tube/ rod , new seal , new bushings , new springs. Looks good. What kind of fork oil and how much in each ? Any special tricky thing to do or watch outs? Tom

[jwonder]

I looked into it and found out that 0W-20 matches the same viscosity traits as the oil they had originally spec'd. Any cheap 0W-20 oil will do!

BMW specs 130cc per fork leg.

Once done, check for leaks at the bottom of the fork.

[Bluebmw52]

Thank you mr J Wonder for technical information concerning the forks of R51/3 , most kind. Could you please direct me to pathway to BMW Archives and best way to get original build data about this 51/3. 527773. With my thanks. Tom

[jwonder]

Tom,

INTERESTING, I just looked up the 1954 owners manual and it says 160cc in the front forks, when the 1951 owners manual says 8 cu in (which is 130cc), and I have ALWAYS used 130cc. I would still go with 130cc.

We probably have the most complete set of documentation available right here on our website.

For the main VBMWMO library site go to: https://vintagebmw.org/library/

For the R 51/3 page go to: https://vintagebmw.org/library/?model=R51/3. The 130cc specification is on the page 17 of the 1951 owners manual.

If you want to read all about oil, go to: https://vintagebmw.org/library/ and type "oil" into the search box and hit return (I know, you need to hit the return key) and you will see everything on oil in the library.

I came up with the 0W-20 viscosity info for the forks. I have done a ton of work on vintage automobiles and we always needed to calculate the old weight specs to the correct viscosity of the oil to match it to the current weight ratings. Thats the right way to do it and after looking at the vintage specs for the oil, the 0W-20 is the same viscosity and honestly more stable in cold and hot at the needed viscosity than the older fork specs. I run it in all my plunger front forks and its great!

Hope that all helps!!!

[wa1nca]

Could you please direct me to pathway to BMW Archives and best way to get original build data about this 51/3. 527773. With mt thanks. Tom

Send info request with serial # to:

info.grouparchiv@bmwgroup.com

Tommy

[808Airhead]

I have been using ATF fluid in the forks with good result.

[Bluebmw52]

Thank you gentlemen for responses to fork questions. I have reviewed mr J Wonder comments and researched more tech info . Amazing. I see the club will attend a 100 year rally at doswell va on June 8. I live an hour and half from Doswell va . I have been to the state fair complex many times. Glad to help interested riders get in position. Motels are limited in the area. Ashland va will be next best town to look for a room as is Fredericksburg va . It is a huge farm,park to camp in . There are large indoor buildings for display . Has this club booked a block of rooms anywhere yet? Thank you. Tom

[Micha]

From the workshop manual.