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mcsherry1328
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VBMWMO #1328
Madison, WI
Joined: 10/27/2006
Posts: 112

As simple and obvious as this question is, I'd like opinions from the experts.
Recently I dismantled my R69S engine to clean the slingers. I've since discovered that one piston is stock and original and the other is a first oversize. It must have been this way for many years as this is the first time I've had it apart.
I'm not sure if I should leave it as is, find a replacement original size cylinder and piston, or have the stock side bored to first over.
Just wondering if any of you have experience with this. Thanks, Michael

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2185
There are several ways you

There are several ways you can go. As you never noticed it, you could just put it back together again, even though it probably creates a slight unbalance in the engine.

For myself, I would measure everything to see how worn each cylinder is relative to it's piston. From that information, and how much I wanted to spend, and the availability of a new cylinder, I would make my choice. You might end up going to 2nd over on both cylinders with new pistons and rings to get everything even.

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mcsherry1328
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VBMWMO #1328
Madison, WI
Joined: 10/27/2006
Posts: 112
Darryl, Thanks for the

Darryl, Thanks for the insight. I have been looking at several options and appreciate your input. I'm also putting an R67/2 back together which I dismantled 25 years ago and have some questions on the rear drive and suspension installations . Do you know of any any members with plunger frame knowledge in the Midwest? Thanks again, Michael

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
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I don't specifically know

I don't specifically know anyone in the Midwest to recommend as a /3 mechanic. Dan Niner at Cycle Works in Kansas City probably knows a lot about them, but I don't think he does restorations, just machine work.

The rear drive on a /3 is similar to a /2, but the ring gear is on the other side of the pinion. You should know that the heavy pin that ties the U-joint to the splined nose of the pinion only goes through one way.

The plunger suspension is a bit weird to take apart and put together, as the guide post that ties the pieces together only comes out one way. If you need to replace the Pertinax bushings (fiber/epoxy short tubes), Mark Huggett in Switzerland has them.

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schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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The only person that I know

The only person that I know in the Midwest that might have some insight would be Dave Clark at Forever Endeavor BMW in the St. Louis area. He worked on my R69S engine...he told me he cut his teeth on the /2 era bikes...not sure how much experience he has in the plunger bikes, but it's work a check.

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Matteo
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Joined: 04/12/2010
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I've done a lot of

I've done a lot of installations of the suspension parts on the plundger frames recently and I developed a few "shady tree" techniques. Post your questions, there may be a few people on this forum that could help.

One tool that I found useful was getting a pipe that is the diameter of the bottom end of the slide that guides the suspension. The bottom end is smaller than most of the rest of the tube. I took an old, unusable slide and had a machine shop turn it down to the smaller diameter. It was so simple, the machinist didn't even charge me for the work. I use that pipe to push up an installed slide. I have to used the weight of the bike to force the installed tube up. A little precarious but no tip overs so far.

When I reinstall the slide, there a several washers that are the bottom of the suspension but those washers never stay centered. I use the same "tool" and slide it from below. It keeps the washers in place and as I bang the "flight" slider down, it pushes the tool out of the way. I lather the washers with grease to help keep them put.

Hope that makes sense.

mcsherry1328
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VBMWMO #1328
Madison, WI
Joined: 10/27/2006
Posts: 112
Thanks Matteo, I appreciate

Thanks Matteo, I appreciate all the tips I can get. I'm sure it will make more sense as I get deeper into assembly.
I will also contact the guys in Kansas City and Saint Louis about some technical stuff. Thanks Darryl and Scrader. Michael

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