1975 R75/6 Install Siebenrock 1000cc Upgrade Kit

[brook.reams]

This bike is my first BMW that I bought new in 1975. It's the first bike I rebuilt. After I put over 100,000 miles on it, I gave it to my son, Branden. In about six years he added another 100,000+ miles on it. So it's time for a top-end refresh. He decided to install a Siebenrock 1000cc upgrade kit that we got from <a href="https://www.euromotoelectrics.com/product-p/pistonkit0072.htm" target="_blank" rel="noopener">Euro MotoElectrics</a>.

Here is video of how Branden did the work.

<strong>VIDEO: <em>1975 BMW R75/6 Install Siebenrock 1000cc Upgrade Kit</em></strong>

 

[stevenrankin]

What have you noticed?

So I have been contemplating the same upgrade of my R80RT, it is getting to be about time to do a rebuild. How much of a performance gain have you noticed? I know doing the kit is cost effective for a straight rebuild but, is there a noticeable performance gain? St.

 

[brook.reams]

So I have been contemplating the same upgrade of my R80RT, it is getting to be about time to do a rebuild. How much of a performance gain have you noticed? I know doing the kit is cost effective for a straight rebuild but, is there a noticeable performance gain? St.

Steve, my son, Branden, said there is a noticeable increase in performance and acceleration. He also changed the main jets from 135 to 150 as it was running lean with the 1000cc kit installed. Not unexpected.

 

[stevenrankin]

Thanks

Thanks Brook, this may be in the bag when the time comes. I love my R80RT but miss the additional power my now gone R100RS had. St.

 

[robsryder]

Another excellent, well illustrated and narrated video from Brooks.

I found it much easier (on my fingernails) to use a piston ring expander such as this from the 'Zon -
https://www.amazon.com/Stens-751-90...S&keywords=piston+ring+expander&qid=169162880

The clamp ring compressor used looks handy. I've long had a set of ring compressors like these -
https://www.amazon.com/Glarks-Compr...628898&sprefix=piston+ring+comp,aps,86&sr=8-5

With all of the bikes that Brooks has worked on, I expect that he has extra wristpin clips. I know that there are likely several still in dark corners in the garage at the house we use to live in. Maybe with increased practiced it becomes easy, but I would always have a few extras on hand, cause .... ping! ... and the clip is gone!

 

[stevenrankin]

floor

Ha ha, I just laid down flooring in my shop to make it easier to see dropped stuff and filled in the spots where zinging parts could fly to. I should have done it twenty years ago. St.

 

[k547]

Lol!
I work on stuff that may fly away inside one of the large thin plastic bags that the dry cleaners return my clothing in.
I save a few of the bags for that purpose. It has been very helpful more than once.

 

[kbasa]

Ha ha, I just laid down flooring in my shop to make it easier to see dropped stuff and filled in the spots where zinging parts could fly to. I should have done it twenty years ago. St.

I'm getting ready to move into a new house and I"m going to epoxy the garage floor a nice solid light gray so I can find dropped parts. Plus, having had a floor like that previously, it really helps your lighting be more even.

 

[barryg]

Did U bore out the engine case to accept the new cylinders? I have a late 70’s R80/; I thought I would need to get the case bored out to accept 1000cc cylinders?

 

[pglaves]

I'm getting ready to move into a new house and I"m going to epoxy the garage floor a nice solid light gray so I can find dropped parts. Plus, having had a floor like that previously, it really helps your lighting be more even.

Since you have one you already know - but I have found those floors to be slick with even the slightest dampness. Rolling a bike around or even just getting off can be a challenge on a slick floor. I had my shop's concrete floor broom finished. Harder to keep clean for sure, but easier not to drop the bike. I learned the hard way on the floor in the attached house garage.

Or maybe I just have the wrong kind of shoes!

 

[kbasa]

Since you have one you already know - but I have found those floors to be slick with even the slightest dampness. Rolling a bike around or even just getting off can be a challenge on a slick floor. I had my shop's concrete floor broom finished. Harder to keep clean for sure, but easier not to drop the bike. I learned the hard way on the floor in the attached house garage.

We had a stained floor back in Mass. and it could be slick, but the chances of me riding motorcycles in the rain these days approaches zero. We've got an epoxy coating in the atrium of our current house and they added some fine sand to keep it from being slippery when wet. You can't see it, but it's there if you walk on it barefoot.

 

[robsryder]

I'm getting ready to move into a new house and I"m going to epoxy the garage floor a nice solid light gray so I can find dropped parts. Plus, having had a floor like that previously, it really helps your lighting be more even.

When we moved I had the basement and garage floor coated with a grey epoxy, but for the small anti-slip pieces embedded in the epoxy I asked for the colors of black, white, and red to be used - sort of an homage to my schools' colors (NC State and Ohio State). Lots of LED overhead lights also! It turns out this is just about perfect camouflage for small washers, screws, nuts and other bits. Such little bits become invisible once they hit the floor. Sometimes use of a broom and a sweeping motion can cause the item to reveal itself, sometimes not. The small screws are very easily findable by walking barefoot on the floor (I generally don't do this). My preference for stainless steel has made use of a magnet less useful in finding lost items.

Once the replacement is secured the lost item becomes more easily found. If I need 2 of something, I will often obtain 5 of the item. To appease the floor monster, I will often just toss the first item over my shoulder in some random location. Then when I lose one other item, my chances of success in locating the lost item are automatically doubled. And I still have enough to complete the task if I can't find any lost items.

Epoxy floors are great. Unless one spills a bit of oil...and subsequently tries to clean the floor with water and maybe Simple Green. Tennis sneakers thus become as ice skates on an ice rink. For a time this helps one develop a keen sense of balance.

[Most of this, or at least some of this, is written as a "tongue-in-cheek" commentary].

 

[Omega Man]

Once the replacement is secured the lost item becomes more easily found. If I need 2 of something, I will often obtain 5 of the item. To appease the floor monster, I will often just toss the first item over my shoulder in some random location. Then when I lose one other item, my chances of success in locating the lost item are automatically doubled. And I still have enough to complete the task if I can't find any lost items.

This is just a sign that you are an experienced professional!

OM

 

[bbhatt]

Did U bore out the engine case to accept the new cylinders? I have a late 70’s R80/; I thought I would need to get the case bored out to accept 1000cc cylinders?

I too am interested in learning about this. I asked my mechanic about adding a big bore kit and he said it wasn't a good idea to bore the case out. Curious if this kit requires that or not?

 

[20774]

The only concern for those considering this is the year of the bike. Up to the 1975 models, the case opening was 97mm, but beginning in 1976, the case opening was 99mm. So you must by the kit that works with that opening. If you want to go from a 800cc to a 1000cc, the Siebenrock kit gives you the new cylinders, pistons, and wrist pins. You just reuse your heads.