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brook.reams
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VBMWMO #7701
Joined: 03/02/2010
Posts: 87

Folks,

It's time for me to get focused on this project if I'm going to ride this bike to next September's 40th anniversary get together back east. I'm putting together my project plan. I'm mulling over an idea (see below) and am looking for information.

First some details about this bike:
0. Odometer shows 37,400 miles.
1. Has dual plug heads.
2. Is a CFO model with 38 mm exhaust NOT the standard 1977 model with 40 mm exhaust valves.

--> THE IDEA I AM MULLING OVER:
============================
Configure this engine to the standard engine specifications for 1977.
That would include machining heads to enlarge the exhaust to 40 mm & purchasing the associated valve components and exhaust headers.
BUT, WHAT ELSE WOULD BE REQUIRED?

I don't know if the CFO models used the same high compression pistons as the non-CFO engines and there maybe other changes that were made to meet the pollution requirements.
--> I'D APPRECIATE DETAILS ABOUT THE CHANGES TO CFO ENGINES VS STANDARD ENGINES IN 1977.

Thanks in advance for any information.

Best.
Brook Reams.

Arvada, Colorado
-------------------------

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Brook Reams-Arvada, Colorado
[Various Two-wheeled Vices, All BMW]
Web Site --> brook.reams.me

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6419
Brook - I see that you posted

Brook -

I see that you posted your question on the Airheads email list...hopefully someone like Tom Cutter or Anton Largiader will weigh in. I went to the archives and searched for "CFO"...you might want to do that and see what kind of information you can find.

Ian Falloon's book mentions that the 1977 models had a deep oil pan, but it was only an option for the early CFO bikes. He also says that the CFOs (through 6183254) had the smaller header pipes and a more restrictive muffler.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

brook.reams
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VBMWMO #7701
Joined: 03/02/2010
Posts: 87
Confirmed 40 mm headers

Hi Kurt,

Thanks for the additional info. The exhaust system will need to be replaced, so I figured I could get the 40 mm headers, etc. Based on info in Bill Stermer's "BMW R100RS" book, the header clamps on this bike do not have the "42" stamped on them, so it's a 38 mm exhaust and valves. Something in me would love to stamp "XXX" over the "CFO" marks on the engine Smile

Best.
Brook Reams.

__________________

Brook Reams-Arvada, Colorado
[Various Two-wheeled Vices, All BMW]
Web Site --> brook.reams.me

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