Tool for piston circlip?

[kstoo]

The last time that I took the barrels off my RS I said that I would not do that again until I found a better way of getting the piston pin snap ring off and on without prying it loose with a screwdriver. Can you recommend to me a better way of doing this?

http://www.maxbmwmotorcycles.com/fiche/FicheZoom.asp?image=Diagrams/B0000027.png

But when I look at this fiche that is not what is on my RS. The ones that I have are just spring steel wire with no 'eyes' for getting a tool into. Is that the problem? Do I have the wrong rings in there?

EDIT:
Never mind ... I would delete this thread if I could. The 1982 RS does have the circlip as pictured in the fiche so that is not a problem. The one that I was having trouble with was a /6 which does have a internal snap ring which is very difficult to get out. OK, I will be working on a /6 again some day so have you got any advice for me in that respect?

[20774]

Like the circlips #11 25 1 253 165 shown at Hucky's page?

http://www.bmwhucky.com/010011.html

If so, they're like the ones on my /2. There should be a groove cut in the wrist pin hole of the piston to let you get something underneath it to compress it and get it out of the groove/hole. I struggled...can't quite remember how I got them out. But a pair of needle nose pliers would be good to reach and grab it...especially if there's a corresponding groove cut in the jaws of the needle nose to wrap around the circlip a bit more.

On a /2 forum, someone mentioned using Teflon buttons instead of the wire circlips...possibly from Arias. I don't know much about those...

[nealart]

^^^ Yes^^^

I just did this on my friend's Bultaco and we cut two very small grooves into the ends of the needle nose pliers to help steady the wire clip in the pliers.

That piston had notches on the sides of the hole to get the pliers in there.

[grumpyone]

The snap rings your talking about are used everywhere especially on guns we work on. They are actually a wire with no ends on them in a groove.
The best and easiest way we have found to remove these little friends is take two scribes that you can hole onto good. Put one point at one of the clips end as a brake and slide the other under the other end. If it pops down instead of outward take a third scrive or small screwdriver and put it into the grove so it cant go back in and will ride over and take the scribe and lift it up and over the screwdriver blade and as it gets up tilt the screwdriver blade to extract.
If there is a load on the clip that will srping out and hit you in the chops or even worse in the eye put a clamp onto the part to hold pressure while you do it some of these contraptions have big jobs for little clips and can fly out with a good blow.
Good Luck
Jim and Esther

[Polarbear]

Yours apparently does not? My /7 has the holes for the right tool to grab onto, so you may wish to buy those going back in:). Randy:thumb :usa

[kstoo]

I took the top end apart completely yesterday on the 1982 R100RS and it was a stinkin' pleasure. This had the external circlip with the eyes to insert a standard tool into and it took about 10 seconds to remove.
On the /6 I had used the proceedure much like Mr. Grumpyone describes above. I wasn't happy with doing it that way but it seems to be the only way. It is too easy to slip and make scratches on the piston in that pin bore area; I did not like that at all even though I don't think that really caused any operational damage.
Thanks for the discussion on this.
I was going at the R100RS topend because of low compression at the rings but now I find that the connecting rod bearings are WAY bad. Do it now.

[kstoo]

Yours apparently does not? My /7 has the holes for the right tool to grab onto, so you may wish to buy those going back in:). Randy:thumb :usa

By searching the fiche it appears that before 1978 the internal spring wire clip was used and after that the piston design changed to an external circlip. It is what it is.

:whistle

[nealart]

but now I find that the connecting rod bearings are WAY bad. Do it now.

How many miles?

[kstoo]

How many miles?

This is an orphan RS; the odometer died and was replaced 16,000 miles ago but I have no idea what the total is. It may very well be over 100k. Just guessing.

[lostboy]

The early piston and wire circlip in R100s is trouble waiting to happen. By the time you get the clip in place, it has yielded and is no longer a proper fit in the groove. Even if you should get the clip in without damaging the clip, the piston is not strong enough to support it and frequently allows the pin to push the clip out, ruining the piston and cylinder. This is why the late pin and clip were developed.

If you are going to keep this motorcycle, I urge you to have the piston machined to accept the later pin/clip arrangement or replace the pistons with either a later type from BMW (this should be accompanied by remachining the squish band in the head) or an aftermarket piston.

[kstoo]

The early piston and wire circlip in R100s is trouble waiting to happen. By the time you get the clip in place, it has yielded and is no longer a proper fit in the groove. Even if you should get the clip in without damaging the clip, the piston is not strong enough to support it and frequently allows the pin to push the clip out, ruining the piston and cylinder. This is why the late pin and clip were developed.

If you are going to keep this motorcycle, I urge you to have the piston machined to accept the later pin/clip arrangement or replace the pistons with either a later type from BMW (this should be accompanied by remachining the squish band in the head) or an aftermarket piston.

Not a problem. The confusion that I created was because I was confusing my /6 work with my R100RS work. The RS has the external circlip so all is well.