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jimbosidecar's picture
Beijing, China
Joined: 01/20/2009
Posts: 1

I recommissioned this bike for a friend's widow. It is stamped CFO on the crankcase near the oil filler. It is wearing 40mm Bings and 38mm exhaust. I've been told these bikes did not come with 40mm Bings. These are ending in 103 and 104. The bike now runs just about perfectly and very fast. Anybody know what carbs they did come with? The ones that are on there look like they came with the bike. Thanks.


1967CJ750 (BMW powered)

schrader7032's picture
VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 7080
Welcome to the forum! From

Welcome to the forum! From what I can tell, the CFO (stands for California-Florida-Oregon) models got the smaller exhaust valves but still got the 40mm Bing carbs. Seems like they then just jetted these bikes differently due to the changes to the heads. According to the Bing book, 103/104 carbs were ideally for the R100S of the period. The R100RS got the 105/106 carbs...Ian Falloon's book mentions that. It looks like the needle jet is a few sizes bigger (more fuel) and the clip position was #2 which is one step richer. But I'm sure the 103/104 carbs work just fine...it would have to do with the internal settings.


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

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