Installing piston pin lock rings

[Einar]

Any advise/tricks/black magic on how I install those highly annoying lock rings that goes on each side of the pin that connects the piston to the crank shaft rod? Preferably without deforming it too much.

I've been trying for an hour without success and ended up scratching the side of the piston and making a mess. I had to stop before I decomissioned the bike in rage.

As always your input is highly appreciated.
Einar

[Tony Smith]

A procedure on which everyone has an opinion, most of them right.

I use my thumbs and forefingers to start the clip opposite the "ends"  into the bore in the piston - I tend to try and have a rag over my fingers in the faint hope that if the clip flies the rag might snag it....

Once the clip is fully in the bore I then use small blade screwdrivers to move it toward and into its groove. Once in the groove I push as hard as I can on the piston pin to make sure that the clip really is home.

Don't re-use a piston clip unless it is an emergency (like your last brand new one just flew to places unknown - pick the used clip with the widest unladen end gap.

Curse BMW for not using proper circlips - these are an option actually and there is no reason not to use them.


Finally you can join an infamous and long running joke. Unfortunately BMW is the joker and you/we are  the butt of the joke.


According to BMW the clips have a flat side and a round side - the flat side is decreed to go towards the piston pin.

I have looked at many new pins and an at least equal number removed from service and I am yet to see the first one with a flat side.


It helps is the pistons are still warm so that you can move the pin easily.

[Einar]

Thanks for the tip Monte and Tony! You are not too late.

I was actually trying to put the circlip ends into the notch but quickly gave that up, so I will try to the opposite way tomorrow as you suggest.

I'm using new clips, they appear to be slightly thicker (and more rigid) than the ones in place, so that makes it even harder.
Anyway, I'll curse BMW sufficiently, take the PIA that is required, and hopefully with your advise get it in place tomorrow.

No flat side on my clips either, not the new ones nor the old ones.

A few scratches on the skirt, I will try to dress it down gently.

[Mike V]

those damned things ... hate 'em.

I have more trouble getting them off, than on, for some reason.  Gotta hold your mouth just right.  I ended up using a deep socket at the appropriate diameter and pushed them home till I heard and felt the joyous "click".  Thought about using a 5lb sledge hammer and cold chisel.  Whatever you decide to use be sure to support the opposite side of the piston not to stress the big end bearing.

I think they were designed just to irritate us.  Probably the same department that designed the '81 side stand and center stand. Seriously.

There's gotta be a special tool out there somewhere in Oz.

[Einar]

Yeah it certainly seems like a practical joke by the BMW team. What a pain!

I was looking for a special tool as well. It might be handy even if it won't be used much, if only to prevent garage rage.

[georgesgiralt]

IMHO, it was common then. A lot of car had this very same system which is lighter than it's circlips counterpart. I think it is part of the R45/R65 design to use more common parts and standardize a lot.
I install both ends opposite the notch then press each side from the opening to the notch and finish with a bit of wood. (at one time I used chopsticks but the bamboo they're made off fray too easily and you end up with filament of bamboo trapped under the clip...)
Working in a big plastic bag is a must if you do not want to buy them by the wholesale.

[Einar]

Hi everyone,

I installed the clips yesterday evening in less than 5 minutes, thanks to your tips. The link to a video Monte attached was also very useful to understand the technique to push in the clip.

I left a few scratches (pictures attached), would be useful to know if it should be a cause for concern.

What worked for me was:

1. Circlip ends go in first
2. A wooden chopstic to progressively push in the rest of the ring
3. A screw driver to gently "click" it in place
4. I found that it was only possible to install the ring putting the ends near the small recessed notch.

And of course a rag in the crankcase opening.

The chopstick didn't give off too much wood and I was able to clean it afterwards.

Thank you! More questions to follow as I am slowly working my way through a complete cylinder rebuild for the first time.

[Einar]

Thank you monte! I thought it was well seated but I will definitely check again if you can see from the picture that it's not completely in place.
To do tonight.

[Einar]

Update here, I have run into some problems:

After successfully installing the clip rings I was torquing the valves when one of the cylinder rods gave in. It appears it has been quick welded due to damaged threads and the welding didn't hold.

So.....I now have to fix the threads etc etc.
Likely to have more questions on the topic, however I will open a new message thread for that.

[georgesgiralt]

BMW used to sell special Helicoils with the proper length. So a shop knowing the airheads and their problems can help.

[Tony Smith]

BMW used to sell special Helicoils with the proper length. So a shop knowing the airheads and their problems can help.

I've Helicoiled a couple and whilst the standard Helicoil is a little shorter than the one BMW supply, they work just fine.

[montmil]

BMW used to sell special Helicoils with the proper length. So a shop knowing the airheads and their problems can help.

I've Helicoiled a couple and whilst the standard Helicoil is a little shorter than the one BMW supply, they work just fine.

CycleWorks sells the l-o-n-g-e-r helicoils for the case repairs. Talk to Dan about your needs. He also sells the tooling to make these repairs but at $225.00USD, you might need to go into business to justify the purchase.

http://cycleworks.net/

[Einar]

Thank you for the pointers and encouragement.
I will find a solution, I am sure. Fortunately my local mechanic is somewhat of an airhead (pun not intended).

And no, at the moment not too discouraged. I was rather scammed by the previous owner, however in a way a blessing in disguise as I am learning a lot, largely due to your valuable input.

New thread to follow.

[Tony Smith]

You local BMW club might have a set of guide plates/jigs to loan out when you drill the cases.

You really are supposed to use a jig, I didn't know such a thing existed the first couple I did, once I knew that jigs existed I tried to control my guilt. Go slow and have a friend kneel in front to confirm drill alignment before pulling the trigger.

Genuine Helicoil sets are devilish expensive, however there are clones. I have been using Ezi-coil fr many years, they cost about $AU40 per set, then you buy a GOOD quality drill of the correct size for that coil set and keep it in the tin with the tap and spare coils forever.

[Einar]

Great tip thank you Tony.

Would something like this do the job?
http://www.ebay.com/itm/V-Coil-Thread-Insert-Repair-Kit-M10x1-25-Compatible-With-Helicoil-Spark-Plug-/331788936660?hash=item4d402965d4:g:9zMAAOxyYANTXiGR

Any way I can identify the thread size (stud is 10mm, I believe) apart from with a gauge?