Hi James, thanks for the post. I didn't realize the original silver turned-to-gold intake tubes were a desirable thing .... I learned something already. So do you think my carbs are not original to the bike? I must say you are all having an influence on my approach to this machine. Thinking .....
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1970 R75/5 #2970531 Restoration
- Thread starter tko11
- Start date
Hi James, thanks for the post. I didn't realize the original silver turned-to-gold intake tubes were a desirable thing .... I learned something already. So do you think my carbs are not original to the bike? I must say you are all having an influence on my approach to this machine. Thinking .....
According to the Bing book, the carbs look like Type 64-3 which James pointed out has two screws to hold the dome onto the carb body. The original would have been Type 64 with four screws. The carb numbers would give it away. James said 64/32/9 or /10 would in the right range...could also be /1-/2 or /3-/4. If it's much bigger, then the carbs are for another model. Not to say they won't work provide the internals are set up to resemble /5 carb settings.
AntonLargiader
Active member
FWIW I have 2970304 I think. A few hundred earlier, made in November '69.
My future brother in law and I were going to buy this bike together to fix and flip, back in '04, and I decided I wanted to keep it so I bought it. It was running on one cylinder, and the owner said he rode with his daughter up and down the street every now and then. I think he never knew how it felt with both cylinders firing, because by the look of the LH carb it had been a LONG time since it had atomized fuel. The transmission was stuck in one gear, the seat was trash, and I'm sure the tires were also. No pinstripes on the tank, so I guess it was a repaint.
I fixed the trans, overhauled the carbs, did whatever else I needed to do and it was a very nice runner. 2.91 final, extra heavy flywheel and a few other details give it away as a very early bike. It now has a 5-speed and I'd like to swap in a later clutch and starter, but it's just not a priority.
Years later, some guys were doing some utility work at the bottom of our yard and I was talking to them about the motorcycles they saw around. Yeah, their buddy had a BMW that he might want to sell. What's his name? Oh, he doesn't have that bike any more, it's up in my garage.
It's a super pleasant bike to ride at around 70~75 MPH. Glassy smooth. And it cleans up very nicely. I don't want to restore it further.
OK, hijack off. I just have a weakness for these.
My future brother in law and I were going to buy this bike together to fix and flip, back in '04, and I decided I wanted to keep it so I bought it. It was running on one cylinder, and the owner said he rode with his daughter up and down the street every now and then. I think he never knew how it felt with both cylinders firing, because by the look of the LH carb it had been a LONG time since it had atomized fuel. The transmission was stuck in one gear, the seat was trash, and I'm sure the tires were also. No pinstripes on the tank, so I guess it was a repaint.
I fixed the trans, overhauled the carbs, did whatever else I needed to do and it was a very nice runner. 2.91 final, extra heavy flywheel and a few other details give it away as a very early bike. It now has a 5-speed and I'd like to swap in a later clutch and starter, but it's just not a priority.
Years later, some guys were doing some utility work at the bottom of our yard and I was talking to them about the motorcycles they saw around. Yeah, their buddy had a BMW that he might want to sell. What's his name? Oh, he doesn't have that bike any more, it's up in my garage.
It's a super pleasant bike to ride at around 70~75 MPH. Glassy smooth. And it cleans up very nicely. I don't want to restore it further.
OK, hijack off. I just have a weakness for these.
Many thanks!
BMW could easily have folded on motorcycle development and production back in the late 1960's. My hats off to that small group of engineers and design team that did the fine work to to bring the /5 into being. We have the bikes we now have due to their diligence to keep it going. Thx much Guys. 
Hijack back ON.
Me too.
Hijack back OFF
Yes!!!!
This is so cool, yep yours just 'a few' earlier. It looks like mine was built in December of '69.
I thought these had a VIN plate with rivets, only a decal here .... is this correct?
Attachments
I wonder if that tag is a replacement. I went to several sites and the show that VIN as being built in January 1970.
http://www.bmbikes.co.uk/chassispages/enginechassis750.htm
http://www.bmbikes.co.uk/chassispages/enginechassis750.htm
About the carbs; the 9-10 carbs on my '73 are the ones installed when I bought it in 1989. No reason to believe they are not originals. I have also seen 9&10's on R75/6's. The 64/32/1&2 or 3&4 are earlier models and thought to be defective in airhead lore. On this 1971 R75/5 I recently picked up, there is a set of 3&4's in the extra parts boxes that came with it. I am confident that there is a good reason they are in a box apart from the bike. This '71 runs very well with the 2 screw, dome top Bings. I will check thru the service record to see when the previous owner did the change. He is one of our Airheads members from Illinois, and owned that bike since 1987.
I suppose the question to the original poster would be just how original do you want it, and at what cost?, in terms of both expense and performance?
Interesting information James, thanks for sharing! My bike currently has other non-original parts on it so doesn't really matter to me either way. Seems to run good as is, so I'll keep them. Interesting though, I was just looking at this bike ... see below. Nice early /5 bike that sold last year (for cheap if you ask me), was built about a year latter than mine and looks to have similar carbs ... was on the show circuit too.
http://bringatrailer.com/listing/1971-bmw-r755-motorcycle/
Attachments
AntonLargiader
Active member
For all practical purposes, the 9 and 10 are the original carbs for that bike. If you need a time capsule you could put the 3/4 on, with their funky spring-loaded chokes and so forth but they were replaced by the 9/10 early on, as in when they were current models or maybe when the /6 came out. There's a reason pretty much every R75/5 has them. My November '69 bike had them.
FWIW I have a '74 R75/6 in the shop with 9/10, a '74 R90/6 with 11/12, and a '76 R75/6 with 13/14. Just to give you an idea when those carbs were introduced.
FWIW I have a '74 R75/6 in the shop with 9/10, a '74 R90/6 with 11/12, and a '76 R75/6 with 13/14. Just to give you an idea when those carbs were introduced.
