Fork oil replacement

[flongr65]

My 81 R65 has 25,000 miles. Is it advisable to change the fork oil and if so any advice on the oil and DIY procedure?
Thanks, Frank

[Bob_Roller]

Changing the fork oil is usually a yearly task .

BMW recommends 7.5 wt oil for the fork, but if you can't find any locally, 10 wt will work as well .

To replace the fork oil, it's a pretty straight forward procedure .

Place a drain pan under the fork leg, remove the small drain plug from the back side of the lower fork leg near the bottom, the drain may be plugged with 'grunge', so you may have to open it up with a tooth pick, or something similar .

Next remove the dust caps from the top of the fork tubes, remove the allen head bolt, you may need to hold the part that the bolt threads into with a wrench, as it is free to turn .

After letting the oil drain out, check the condition of the small copper crush washers on the drain plug for general condition, if they are alright re-install the drain plugs .

Use caution when re-installing the plugs, you can strip out the threads in the fork leg if you tighten it up too much !!!!!!!!!!!

Add 190 ml of fork oil to each fork, then re-install the allen bolts in the top of the fork, and re-install the dust caps .

[flongr65]

Bob, thanks very much. Where do you buy the 7.5 wt oil?
frank

[Bob_Roller]

A BMW dealer is about the only reliable source for that weight oil .

Some have mentioned using equal amounts of 5 wt, and 10 wt oil of other brands .

I have a local BMW dealer, so I get my oils from there .

[montmil]

Check out these DIY articles. Muy helpful.

Only odd ball tool you'll need is a 14-inch 1/4 drive extension with a 13mm socket on the end. This will allow you to easily secure the lowers to the fork legs after replacing the seals. Don't count on the 6mm Allen screw being tightened from the bottom of the fork slider.

http://www.ibmwr.org/r-tech/airheads/forksealreplace.shtml

http://w6rec.com/duane/bmw/forkseal/index.htm

Some folks use a 10wt fork oil but I stick with the BMW dealer-supplied 7.5wt in my '81 and '83 R65s.     Monte

[flongr65]

thanks guys.......

[disco51]

Sorry to bring this back up...  quick question.  New owner of a 79' R65 in great shape.  
I'm trying to take down the front fork to put on fork gaiters and change the fork oil and have read this post among others.  When I look up the bottom of the fork (after removing the tire, etc.), I just see a big Allen bolt and do not see the 13mm hex surrounding it.  Should I just go ahead and remove this to release the fork down?  I was surprised to see this as I was anticipating needing that offset 13mm box wrench.  Don't want to undo something I can't fix.
Thanks for the help....

[Barry]

Yes go ahead and undo the big Allen bolt but the damper rod is likely to spin in stanchion unless you hold it from the other end with a socket on a long extension. This will mean removing the spring.

Sometimes you can shock the Allen screw free without holding the other end. I usually manage to do that. Certainly an impact wrench will do it.

[disco51]

That 10mm allen bolt is really stuck.  Any ideas for getting this loose?

[georgesgiralt]

Hello !
To put gaiter, you can remove the fork from the top by unscrewing the locking nut on the triple clamp. Then remove the fork, insert the gaiters and then put the fork back in.
Torque the bolts as specified as it is a delicate part of the bike...
To remove the oil, if I'm not mistaken, there are tiny nuts under the callipers to let the oil drain. And then put the oil back through the upper Allen bolt at the top.
Change the washers if you have some.

[Barry]

Yes,

If you just want to install gaiters and not renew the seals or overhaul the fork internals you coul just drop the stanchions out of the triple clamps.

There is no particular reason for the Allen screw to be excessively tight. It's just threaded into the bottom of the damper rod and has an aluminium crush washer to act as an oil seal. I can't recall the torque setting but it's not high. I'd guess 20 something lb-ft.  Unless you have a hexagon bit for your socket set, the Allen key has to go in the wrong way around and a close fitting tube used on the short end to provide some leverage.

[disco51]

Thanks, I tried that as well in frustration last night.  I loosened the upper and lower triple clamp, but couldn't get the stanchion to come down.  Again, I'm relatively new at maintanence, so I wasn't sure how much force to put down on the stanchion to get it to slide out of the triple clamp.  Do I need a mallet?  Does anyone know ofhand the torque needed to retighten the triple clamp?  
I thought about buying a hex bit for my socket set today with an extender to go after that 10mm allen today.
Aside question, when starting this process with the wheel elevated in the air, I noticed the front brake pads were making contact with the disc without the brake engaged.  They look like new pads.  I could rotate the wheel a single rotation before it stopped.  Not sure if this is correct or if I need to adjust these so they do not touch.
Thanks for all the help.

[Barry]

It's usual to drive some hardwood wedges into the gaps on the triple clamps. That will slacken their grip on the stanchions.

Can't remember the torque off hand but is fairly critical with a steel fastener in alloy so don't guess. Someone will probably chime in before I get home and check.

A little drag on the brake pads is normal but only one turn of the wheel sounds excessive. Likely to be stiction in the caliper pistons.  Short of caliper overhaul you could try exercising the pistons back and forth a few times.

[montmil]

1979?

Disregarding the bike's mileage, it may be a very good idea to pull the fork innards and check if the rubber "bumper" has disintegrated as they most often do. Increases the fork clanking you may be experiencing. You'll find the remnants in the bottom of the fork lowers, usually in the form of black silt.

If the large Allen machine screw is stuck that tight in the fork lowers, you're going to need to try a long extension to the Allen wrench or purchase a socket-style Allen. If the screw begins to turn, but does not extract, you must disassemble the fork upper and lower components. Then follow the above posted tips for extraction.

Hardwood wedges -not soft Pine or other- tapped into the triple clamp gaps -not so far as to damage the clamps- and some soaking with WD40 or PB Blaster should get you moving. Remember, they're supposed to bit a very snug fit.

Do you have a shop manual on hand?

[montmil]

Found the photo... finally.

This is what the OEM Rubber Baby Buggy Bumper ring looks like when age and chemicals attack. My 1981 R65, shortly after I purchased it, during a post-buy maintenance survey.