Forks breakdown

[Rob Valdez 79 R65]

I could have sworn I saw a photo of someone (here) using a 3-jaw gear puller to depress the spring.



I could be wrong.

[Bob_Roller]

I made a post a while back, about using a three jaw puller .

You reverse the jaws so they sit against the fork tube ( I remove the forks from the bike when I work on them) .

Place something like a piece of an inner tube on the upper fork tube, put the puller on, then use hose clamp(s ) to secure the puller, then use the screw to depress the plug to gain access to the wire circlip.

[mimmo66]

Here's the best tool I have for opening / closing fork tops with one hand.
One leg is 5", the other one is 6.5"

The arms have indexing on the top to allow for different angles/ configurations

The "legs' bolt right on top of the triple tree, one side on top of the handlebar mount closest to the fork, the other on the opposite side right under the triple tree edge if I remember correctly.

The arms can be made by using any flat piece of sturdy metal that you can both drill and bend to suit your genius.

I also use the same little guy on the K75c and I spend more time securing the 'legs' than anything else.

The whole operation for me has become a 'trifle' since using it.

Hope this helps,
Domenico

[R65Guy]

Excellent!  That is similar to what I had in mind - using 2 legs.  I hadn't considered making the legs removable like that.  That makes it much more versatile.

Neal

(Hi NHMAF - I lurk a lot so don't talk about me Hope to see everyone in PA next July!)

[Rob Valdez 79 R65]

Hope to see everyone in PA next July!

Missouri to PA on the R65?  No, must be the oilhead...

[Barry]

Not as good as a proper tool perhaps but  I do it single handed with an Allen key.

Leave the the filler screw in the top plug and insert The correct size Allen key.

With a large screw driver press and hold the plug down and turn the Allen key until it jambs under the handle bar. I also tie the Allen key back for extra security. This holds the plug down while you remove the circlip with both hands free.

Can't say if it works on US high rise bars though.

[R65Guy]

Hope to see everyone in PA next July!

Missouri to PA on the R65?  No, must be the oilhead...

Yeh, I don't ask the R65 to do the high speed pack mule stuff.  She is much happier with the weekend backroad jaunts.  For our 30th anniversary together I am gonna treat her to a complete end to end mechanical detailing over the wintertime to show I still care

[bjamesw]

If you have a carpenter's vise in your shop it comes in real handy for removing/installing that circlip.  

The pin right in the middle of the photo lifts a 'dog' above the bench top allowing the vise to clamp large objects on the bench surface. Perfect for this job.  Secure a 'stop' (i used piece of 2x4 screwed into the benchtop) to block the bottom end of the fork assembly and use a deepwell socket against the vise dog to compress the plug.  I found the easiest way to remove the circlip is with a sturdy fine needle pick.  Worry it under the clip at a point near the gap and once the pick is under the clip use the pick to leverage the clip up and out of the groove toward you.  

When reassembling there are a variety of suggestings for getting the oil rings compressed and beyond the upper lip of the fork barrel's ID. I'd been using a rolled business card for years, but was frustrated each time by having to find precisely the right hard and thick card.  The paper card is single use since it swells with oil.

I finally measured the lip (mine is almost precisely 1mm so I assume that is similar across the board) so I hunted around the shop and the kitchen for a piece of hard polyethlene 1mm thick.  Not too hard really since there are so many food savers, lids, buckets, etc around the average house that 1mm is easy to find.  I happened upon one of the kid's ancient snow sliders rolled up in a corner of the garage.  Red polyethlene exactly 1mm thick.  I cut a strip exactly as I would have cut the business card, rolled it, slid it in the barrel, and installed the wiper with rings smooth as buttah.  The red plastic shim is in my toolbox now permanently.

Incidentally, if you ever get the chance to grab a well built one of these vises by all means do so.  I don't do much wood work so I never gave them a second look.  But I found two brand new Craftsman horrifically heavy versions (must have been from back when they still made industrial quality stuff) at a garage sale.  Ten dollars each.  Insanely good deal.  I installed them and soon found them to be really really handy on an almost daily basis.

[mongrel]

Hi im trying to find out how much oil to put in my forks, i have an 86, r65 mono. mr haynes apears not to know. :-?

[Bob_Roller]

I don't know if there is a difference between the twin shock forks and the monoshock forks, but if you are just draining and refilling the fork, 190ml of oil will do, if you have disassembled the forks for a seal change, 220ml of oil is required for the twin shock bikes .

[Barry]

Your frame and forks are the same as an 85-  R80. I think the forks may be similar to those fitted to the K bikes of that era which use more fork oil than the twin shocks.

Anyway it's easy enough to estimate by thinking about how they work- unless the oil level is at least above the damper piston then the damping just won't work properly. What I would do is measure the volume as you fill them until the level is about 1" above the piston top measured with a bit of welding rod down the centre of the spring. If that takes some volume vastly more than 190cc then you know that they are not the same as twin shock forks and have to look elsewhere maybe check out the volume used for K forks and 86 R80 forks.

Come to think of it these bikes were made in small numbers and no longer mainstream models compared to the K's so BMW will have done a parts bin exercise - which we know they did by scrapping the old short wheel base 248 frame so you can almost bet money they are K forks or based on them.


Edit: I just looked in Haynes and your right there is no volume listed for an 85- R65's but there is a volume of 300cc for 85- R80's.

Here's a definitive test that will tell you what forks you have. Measure your stanchion diameter. Twin shock R65s are 36mm and 85- R80's are 38.5mm which explains the higher volume of 300cc.

[Rob Valdez 79 R65]

You might need to post this question on Boxerworks.  
The only thing unique about the mono-shock R65's of the period was it's engine displacement.

[mongrel]

many thanks , 300ml seems to work well, bike tracks perfectly, and the damping seems fine. once again thank you.