The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Nice_One_Son on October 18, 2010, 03:00:22 PM
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Hi All,
I am just about to start to take the forks apart. I have the Clymer manual, but it doesn't seem that clear.
Any tips before I start please?
Cheers
Chris
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About the only problem areas are getting the wire circlip out of the top of the fork tube to begin the dis-assembly process .
You need to push down on the top plug, while trying to remove the circlip, sounds a lot easier than it actually is !!!!
The other is getting a 13 mm socket down inside the fork, while using an allen wrench on the bolt at the bottom of the lower fork tube, to get the damper assembly out .
I take the forks off of the bike and place a couple pieces of wood in the jaws of a vise to hold the fork during dis-assembly .
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There is a lot of information on here about rebuilding the forks.
Here is a post of mine with two relevent links: http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1270506405/5#5
And when it comes time to refill them, you might find this tool, from Mike's XS supply to be useful:
http://www.mikesxs.net/products-7.html
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.mikesxs.net%2Fparts%2Fimg250%2F35-1084.jpg&hash=32e53af184cfa0670e8f14c7cfb272cf6a2076bb)
Fork Oil Level Gauge for adjusting the oil level on all XS650 forks.
Adjustable ring measures oil levels from 0-300mm. in 50mm. increments.
60ml. capacity syringe adjusts fluid levels. $15.00 USD Ea
I went to Tractor Supply and bought a huge syringe for livestock, but I couldn't find a tube that fit over the end quite tight enough, and the syringe leaked air, which didn't help.
I now have one of these waiting for my next fluid change.
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A 13mm 1/4 drive socket on about fourteen-inches worth of extensions will reach the bottom on the for legs. Helped will hold an Allen wrench in the fork lower to keep the damper rod from revolving, revolving, revolving...
The circlip in the top fits into a machined groove in the upper fork leg. Get a helper. Have said helper push down on the upper fork leg cap bit. You may then use a small, flat blade screwdriver to catch an edge of the wire clip and turn it perpendicular to the axis of the fork leg. Then, grab it with needle-nosed pliers and pull it out.
Sounds difficult. Easy with three hands.
The fork spring will want to come out so be careful with sensitive body parts, such as eyes and teeth. ;D
Monte
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I have two sets of front ends and rebuild them every year alternatively as to keep a set ready to install at hand.
Some of the lessons I've learned on the 81 onward model:
Use a vice to hold the lower as you undo the retaining allen screw, it helps!
Do not use any choke cleaner in the lowers as it will melt the damper rubber at the bottom, guess how I found out?
You can make an easy jig that bolts on the upper triple and screw in/out the top nut as you remove the top circlip, very easy to do and effortless, just need one hand!
Upun rebuild use thread sealer and some loctite blue on the bottom allen screw and let dry before refilling, otherwise leaking might be a possibility.
Bump up the fork oil level to 280/300cc with 7.5weight and if you have good stock springs it will work great, same as having progressive springs from my second set.
When remounting the forks ( this might be the time to install gaiters) make sure they are aligned.
The axle (slightly lubed) should go through the whole assembly with little to no effort,
it helps if you leave the double triple bolts securing the fork tubes a little loose as you're refitting the whole assembly, don't forget to go over all the bolts to make sure they're tight once done!
Hope this helps
Domenico
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Yes, those top caps that have to be pushed down whilst digging out the circlip - I didn't have a seal-puller (I think that is what some have used), and as I do most of my work in the middle of the night, I couldn't call on my neighbor.
After some frustration, I decided I needed more weight on my side.
This is the tool I came up with. That is the handle to my impact screwdriver:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F122139709%2Fmedium.jpg&hash=b8c00212819a6654461c0e5553cf2e6f8ba77948)
Here are some photos from my 1979 forks. I'm not sure, but '81 internals may have differences.
http://www.pbase.com/tomfarr/gallery/forks
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Bump up the fork oil level to 280/300cc with 7.5weight and if you have good stock springs it will work great
Domenico
That's a pretty radical increase from the stock 190cc (or a little more if the forks have been rebuilt).
I might try it Do you know what level that gives you using the dipstick method (normally 20 - 50mm above the damper piston top)
Do not use any choke cleaner in the lowers as it will melt the damper rubber at the bottom
I'm curious about which bit of rubber you found. Unless my forks are missing something there is nothing made of rubber in the lower fork leg (except the seal). There is only the topping out bush in the fork stanchion and the new ones I bought are more like polyurethane.
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Guys,
As always a big thank you.
I'll let you know how I did...
Cheers
Chris
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Is it wise to use some duct tape or something to make sure the rachet extender and it's 13mm socket stay together and not come apart inside??
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I'm curious about which bit of rubber you found. Unless my forks are missing something there is nothing made of rubber in the lower fork leg (except the seal). There is only the topping out bush in the fork stanchion and the new ones I bought are more like polyurethane.
Barry,
The part I am referring to is called Support for Damper Pipe #18 as listed in the attached picture, whatever it's made of it melts with carb cleaner guaranteed.
My oil quantity of 280cc is just a subjective information as I've tried 220 cc to 250cc with very little difference than the reccomended oem level.
This considering I'm about 170 lbs. fresh stock springs, no preload spacers, and about 20 lbs of dead weight from miscellaneous items I carry at all times. When touring I easily add up to 50/60lbs of extra load.
Just like any other aspects of tuning, forks have many variables that can be changed to attain different results.
If you're not satisfied with your current setup try play with it till you get it to where you like.
Ciao,
Domenico
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Is it wise to use some duct tape or something to make sure the rachet extender and it's 13mm socket stay together and not come apart inside??
Only if your ball & spring on the connections is not tight, I would say.
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The part I am referring to is called Support for Damper Pipe #18 as listed in the attached picture, whatever it's made of it melts with carb cleaner guaranteed.
Item 18 does support the damper rod or at least centre it at the bottom of the fork leg but they are more commonly known as an oil lock piece. It's purpose is to provide a hydraulic bump stop as the slightly tapered top hat shape enters the lower part of the damper valve body during the last few mm of fork travel.
Mine was made of metal and I thought they all were on R65's but you live and learn.
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I've found that ~230cc of 7.5 weight oil seems to work pretty well for me with a full drain/rebuild in each fork leg.
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You can make an easy jig that bolts on the upper triple and screw in/out the top nut as you remove the top circlip, very easy to do and effortless, just need one hand!
Domenico,
Any chance you have any pics to share of your jig. I am getting ready to build one before diving into my fork rebuild project this winter. No need to reinvent the wheel, errrr I mean jig, if I don't have to! I did it once before without a jig and told myself - not again!
Thanks for all your input.
Neal
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Neal !!
Long time, no see!
It sounds like this fixture/jig could be very helpful to all of us who sometimes can't get a helping hand in the garage..
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I could have sworn I saw a photo of someone (here) using a 3-jaw gear puller to depress the spring.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fecx.images-amazon.com%2Fimages%2FI%2F31gkpi5BJsL.jpg&hash=197a87a53ae44bbd2361a01dfc669805f01c33a3)
I could be wrong.
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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.
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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
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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!)
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Hope to see everyone in PA next July!
Missouri to PA on the R65? No, must be the oilhead...
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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.
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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 :-*
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If you have a carpenter's vise in your shop it comes in real handy for removing/installing that circlip.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.stockphotopro.com%2Fphoto-thumbs-2%2FBAD7K4.jpg&hash=7958767d1690ca156c9f97ed00c9a166545dc188)
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.
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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. :-?
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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 .
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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.
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You might need to post this question on Boxerworks (http://www.boxerworks.com/forum/).
The only thing unique about the mono-shock R65's of the period was it's engine displacement.
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many thanks , 300ml seems to work well, bike tracks perfectly, and the damping seems fine. once again thank you. :)