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Andrewbaron78
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Portland, OR
Joined: 08/26/2014
Posts: 3

Hey All,

This is my first post, but I've already gained a ton of knowledge about how to work on the 1964 R69S I inherited from my dad, so thanks in advance for the continued wisdom. Recently I decided to tear the motor down to clean the oil slingers and do some other much-overdue maintenance on the bike. I've got the motor out of the bike and the cylinder heads are off, and I've run into a problem getting the wrist pins out of the pistons on both sides. The pins moved back and forth freely in the pistons after I removed the clips, and I followed the directions laid out in the Barrington manual to heat the pistons until they expanded and I could take out the wrist pins, but the pins won't come out. I tried using a screwdriver and a couple gentle taps with a rubber mallet to ease them out of there, and it only made the wrist pins harder to move back and forth, it didn't punch them out either end of the piston. I don't want to hammer at them too hard and bend the connecting rods, but now they're kind of half-seized in there and I'm stuck. Anyway, if anyone out there has any expertise in this area it would be much appreciated.

Thanks,

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Andrewbaron78

808Airhead
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VBMWMO #7677
Joined: 08/05/2009
Posts: 1018
I will bet what is happening

I will bet what is happening is the same situation I just experienced with my rebuild. The piston pins for some reason bang on the circlips and this forces the groove where the circlip sits to widen and the piston alloy gets displaced and reduces the size of the bore in the piston pin hole.
You can carefully razor blade/file this edge away or make a piston pin removal tool using a socket slightly larger than the pin,a long bolt/nut/washer,and you can pull the pin through with the long bolt and into the socket. I saw this on both of my rebuilds so far,the piston pjin bashing on the circlip. Look closely,you will see the raised edge on the outer side off the circlip groove.

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Thomas M.
R69s - R60/2 - R67/2 - R51/3

malmac
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VBMWMO #8751
Toowoomba, Australia
Joined: 06/29/2014
Posts: 300
Home made piston pin removal tool

1600pxx994px

I knocked this up years and years ago - to do just what you want to do.

It did the job but it is not very pretty.

Mal

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mal - R69s
Toowoomba- Australia

capebretonmarkbmw
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VBMWMO #8407
Joined: 01/03/2011
Posts: 310
I use a wood dowel

Being a cabinet maker I have reached more times for wood to help removing wrist pins from pistons . I do heat the pistons and then use a (i THINK ) 1'' dowel and hammer them out . I think that you have put uneven pressure on the pins and they are somewhat bound. It is a good idea to check the groove for the clips as well and clean them up as stated above.Mark

VintageSalesand...
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VBMWMO #7368
Corona, CA
Joined: 03/24/2008
Posts: 296
Rods

It is important that, after you have the pistons off, put a wrist pin back in both rods, and use a couple of prisms (perfect square metal bars) to check for rod straightness. If the rod has a bit of a twist or bend in it, it will bang the wrist pins against the circlips as mentioned above. Use a fork like tool to straighten the rods and it won't happen next time.

Jeff

Andrewbaron78
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Portland, OR
Joined: 08/26/2014
Posts: 3
Thanks for the feedback, all.

Thanks for the feedback, all. It's really helpful. 808 Airhead, I'm assuming when you talk about the cir clips, you mean the groove on the outside of the wrist pin where the clips sit, correct? I looked in there, and a friend who works on these for a living made the same suggestion you did, so I took a scalpel and worked around that groove until it was flush with the rest of the piston bore, but that didn't free the pins, and as I tried to knock them out gently with a dowel they only got more stuck and harder to move back and forth. It feels like there's something hanging them up from deeper in the piston bores. I'll try to file out those cir clips a little more and see if that loosens them up. Backup plan to that will be to fashion a tool or go the wooden dowel route and straighten the connecting rods afterward.

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Andrewbaron78

capebretonmarkbmw
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VBMWMO #8407
Joined: 01/03/2011
Posts: 310
How much

How much can the wrist pin move before it starts to bind? Are you heating up the piston ....I used a heat gun and got the piston up to around 150 deg f . Since this is causing some trouble I would not use a dowel and a hammer but a puller and have a steady force applied . To much shock on the connecting rod big end . Mark

R68
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Joined: 08/20/2008
Posts: 466
Don't...

...here's the tool you need to buy or borrow. The lawnmower or small engine repair shop in your town will have this. Don't fuck up your Dad's piece-of-industrial-art R69S motor...

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Andrewbaron78
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Portland, OR
Joined: 08/26/2014
Posts: 3
Yeah, I think pulling rather

Yeah, I think pulling rather than pushing is the way to go at this point. R68, what is that tool called? I'll start making the rounds this weekend trying to find one.

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Andrewbaron78

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