Sorry - peripheral just means "around the outside" or "around the edges" - so, for example, if you walked around the edges of a piece of property you'd be walking the periphery. Anyway ... here are some pictures to make it more clear, or at least I hope so.
http://falcons.dyndns.org/links/open/bmw_pistons/
Cheers, John
BTW ... as of Tuesday of this last week I'm officially RETIRED! I'm really just getting used to the idea, figuring out what to do with my time.
One thing I'm doing as soon as my daughter graduates this June, is hopping on my '88 R100RT and riding from Northern California back to New Hampshire to be there in time for my aunt's 85th birthday. I'm going east on a somewhat northerly route, through Yellowstone, etc. I'll stick around New Hampshire for a bit (one or two weeks, I guess) and then plan to return home by way of the South, Texas, and the Southwest.
I'm planning to blog when something strikes my fancy ... probably here: http://www.cyclecircuit.blogspot.com
All told the trip should put another 10,000 miles or so on the odometer. I'm looking forward to it.
John
R100S top end
Re: R100S top end
That sounds like an excellent thing to do John!
will check your blog
Have a great trip
cheers
Mal
will check your blog
Have a great trip
cheers
Mal
Re: R100S top end
Wow, that peripheral squish band is indeed pronounced, here on an alleged R90S piston: 

Re: R100S top end
Oh wow, no mine's not like that. That's pronounced!Tim Shepherd wrote:Wow, that peripheral squish band is indeed pronounced, here on an alleged R90S piston
Well the R100/7 now has a S top end. It was one of those jobs that took twice as long as it should have. Had to stuff around with different pillow blocks under the rockers, they took some getting out. Then I found out that 32mm throtttle cables are too short for 40mm carbs. Then one of the carbs wouldn't stop pissing fuel. I kept taking it off and pulling it apart and reassembling it, like I had OCD. I fixed the leak but it wouldn't idle for shit. And I couldn't get that 'ken sidestand spring on no matter what I did, I gave up and wired it to the frame. I was beginning to think the whole exercise was a really bad idea.
Just as it was getting dark I finally went for a run. WOOOO- HOOOO does it ever lift its skirt and get moving!! Way more grunt than the /7 and it piles it on as the revs climb. The /7 hated to rev. I haven't ridden too many other boxers, but I think it compares well with Steve's 78RS and that bike has a sweet motor.
But I think my fuel economy will be tragic. Its too much fun opening that throttle!!
Re: R100S top end
On yer Mal! Well done to get it all sorted.
I'd like to have assisted with your questions but had no sensible advice to offer.
Fuel economy, bah humbug.
I'd like to have assisted with your questions but had no sensible advice to offer.
Fuel economy, bah humbug.

Lord of the Bings
Re: R100S top end
I just mounted all the sidestand and centerstand springs on my project bike, the easiest way I've found by far, is to use a long philips screwdriver: first hook the spring to the frame mount, then, using the stands mount pin as a fulcrum, snag the spring with the end of your screwdriver, you may have to hold the spring there with your finger whilst you stretch the spring using the pin as a fulcrum, and then pull the screwdriver towards you, sliding it on the pin until the hook is positioned over the groove. then it's wiggle, giggle and Bob's yer uncle (or you missed the groove and you get to try it again) It takes less than 30 seconds per spring, once you get the hang of it... Note: this works best with the centerstand in the down position, but on the sidestand in the nearly up position.
Re: R100S top end
...or use one of these. I had one come with the kids trampoline kit. It's a handy tool to have in the shed.

Cheers, Steve
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.
Re: R100S top end
So I will just go buy me a trampoline then ...SteveD wrote:...or use one of these. I had one come with the kids trampoline kit. It's a handy tool to have in the shed.
Re: R100S top end
Mal S7 wrote:So I will just go buy me a trampoline then ...SteveD wrote:...or use one of these. I had one come with the kids trampoline kit. It's a handy tool to have in the shed.


Bunnings sell really small cheap trampolines with great big spring hooks! Just the ticket.
Cheers, Steve
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.