R68 center-stand vs muffler quandary

[Grant R26]

I’m working on a 1953 R67/2 that appears very original, vin 614864. According to the Barrington Data pages, this bike was offered with straight pipes and swallowtail non-cutout mufflers. BUT…this bike is fitted with the cutout mufflers. Indications are that these mufflers were not adopted until a few months later AND cutouts were apparently only coupled with the S-bend pipes.

Cutout mufflers don’t seem to be available anywhere, so I ordered, per Barrington Data pages, the Swallowtail with Hanger version. But they won’t fit with the narrow-version center stand.

The 190mm narrow center stand feet comes up neatly into the cutouts and would hit a standard non-cutout muffler. ( see photo )

I have considered that the S-bend header pipes might give me enough outboard shift to allow the new mufflers to accommodate the narrow 190mm center stand. But... before I order from Salis, I hope that somebody out there might have advice for me.

Question:
a) do I change to S-bend pipes and my new Swallowtail-with-hanger mufflers and hope the 190mm center stand will clear inboard of the mufflers?

Or

b) As my work-around, do I convert to a 250mm wide center stand and stick with the current (original?) straight pipes and Swallowtail mufflers ? ( the assumption being that the wider center stand feet will sit outboard, clear of the mufflers.)

Very grateful as always with any advice you can send my way. ( and apologies for the long winded posting)

Grant MacNeill in Toronto. (and Nova Scotia)

[R68]

Typo? 614864 is not an R68 serial number, and I think 654864 might be a very late R69?
As for exhaust systems, have you considered the ISDT systems? Very expensive, but I believe made by Keckheisen and almost in the category of industrial art! Solution to your center stand issues?
As for the muffler you are showing, I've never seen R68 mufflers of either type with that cutout; sorry, but someone else may know more?

[Grant R26]

Hmmm...that is strange as this is the correct matching number and year is 1953. On page 518 of the Barrington book on the data pages they list the R68 for up to serial 650000 as straight pipes and swallowtail with hanger. then from 650001 the list as coming factory with S-Bend pipes and Swallowtail with cutout. These cutouts were only apparently around for a short time as by 9/1/1953, Barrington states they switched to Torpedo with captive nut.
We are just trying to figure out a way to make this work either by changing pipes or center stand. Vetch will know for sure if he is monitoring this page.
The owner has no interest in switching to ISDT and wants to keep the bike as original. Thanks, Grant

[schrader7032]

The R68 serial numbers start at 650001. Vech's still has this page up for serial numbers:

http://www.benchmarkworks.com/articles/tech/serial.html

A 614xxx sounds more like an R67/2.

[Grant R26]

Thanks Kurt...so the plot thickens.

My part in this adventure is as "the buddy who finds parts" for all the BMW owners I know who are not internet savey.
I've only briefly looked at the bike to verify the cutout mufflers and next I'll verify if it is indeed a R67/2. if that is the case, then according to Barrington's data, it should have the s-bend pipes.

the problem remains though, how to fit an exhaust system with the swallow tail mufflers without cutaway. change out stand or fit with S-bend pipes
I see that in sept 1953 they changed to torpedo with captive nut but that still poses the question about the feet of the center stand clearing the muffler without the cutaway.
Still, very useful to know that this bike must be a R67/2. I will get to the bottom of this.
Thanks Kurt

[Grant R26]

Kurt
it is indeed a R67/2.
Grant

[R68]

Perhaps someone has placed R68 R69, R69S heads on your R67/2 (it's a easy modification), but you'll need to match the headers to the type of head used (R68 or R51/3, 50, 60, etc)?
Keep in mind that the salami or torpedo muffers using "S" headers were an upgrade required by the German noise regulations of the time, so a motorcycle originally sold with fishtail/swallowtails could have been upgraded because of the new laws?
The peanut gallery would like to see a picture of this motorcycle.
Finally, that muffler with the cutout you show may have come from a prewar twin, ie. R5, R51?

[vechorik1373]

You could always change to the center stand that matches the exhaust system you have.
That is the simple fix.
The part numbers are, and they are both available:
46 52 4 028 026 is the narrow stand 190 mm
46 52 4 028 028 is the wide stand 230 mm
And I will add that perhaps your existing stand is bent. Center stands were meant to hold the bike up only.
If the previous owners in the past allowed their 400 lb girlfriend to pose on the bike for photos, you can guess the results..

[Grant R26]

Vech !! how the heck are ya ? I hoped that you would eventually see my post and tell me the solution... but it is summer and we all have things to do.

Just staying cool down there in the deep south must be a challenge for you these days!!

I'm 99% sure this bike has never been tampered with. Though Barrington says it should have S bend pipes. The mufflers with cutouts seem to be more or less, correct to period. That said, I recall you advised me once with my 51 R51/3 how often the mufflers changed due to supply issues.

Either way, these mufflers with the cutouts are rotted out and I've replaced with the swallowtail with hanger which seem to be my only available option these days

So...how to proceed; do I use the wide stand: 46 52 4 028 028 230 mm with the existing straight pipes and hope the feet fit outboard of the new swallowtail mufflers ?

(This was the only thing that worked with my early 1952, half hub R51/3 barn find.)

OR...do I stick with the narrow stand...bent or not... and swap to S-bend pipes and hope that the S-Bend shifts the mufflers outboard enough for the existing narrow center stand to clear inboard of the mufflers without the benefit of cutaways ?

My money is on the wide stand solving the problem but hope you can advise;


Do you think this is the best plan; straight pipes with swallow tail w/hanger and wide stand ?

All the best to you Vech!

Grant MacNeill, The Twelfth Fret Guitar Shop, Toronto ( semi retired ...grin)

[vechorik1373]

Grant,

you said: how the heck are ya ? I hoped that you would eventually see my post and tell me the solution... but it is summer and we all have things to do. Just staying cool down there in the deep south must be a challenge for you these days!!

THAT is what Air Conditioning is ALL about!

Now, concerning R68 exhaust.
Early bikes, 1950 through Sept of 1953 came with straight header pipes, (not the S bend) and were equipped with the bird tail (swallow tail) mufflers, NOT the fish tail. The single slash fish tail are a prewar design.
18 12 4 090 003.1 is the new part number for the Right side.
18 12 4 090 004.1 is the new part number for the left side.
They are used with narrow side stand. Measure yours, see if it is bent out! See the dimensions in my previous post.
Mark Huggett GMBH shows them in stock. Call them! www.bmwbike.com

Later bikes, from Oct 1953 to the end in 1955 (due to further noise restrictions enacted by laws) were equipped with the S bend header and the salami style mufflers with the notched side. This style was retrofitted may times, to comply with noise regulations in Europe after the original system had rotted out..
18 12 4 000 003.2 is the right side, 18 12 4 000 004.2 is the left. They are used with the wide side stand.
Mark Huggett GMBH shows them in stock. Call them! www.bmwbike.com