1973 R75/5 Rebuild Project Journal

[brook.reams]

Folks,

I just posted a blog, 1973 BMW R75/5: Tear Down to the Frame, showing the tear down of my wife's R75/5 down to the frame.

You will find links to other sections I've written on this project on the right side of the page. Feel free to post any comments, questions, tips, etc. I greatly appreciate the feedback, and I hope this information is helpful.

Here are a few of the pictures I took along the way.


In the Workshop Before the Tear Down


Me with Fairing, Seat, Tank and Front Fender Off


Wiring Harness Removed from Frame and Engine


Ready To Remove Swing Arm, Transmisson and Engine


Engine Out of the Frame


Naked Frame Ready for Powder Coater


Best.
Brook Reams

[kantuckid]

I'll keep an eye on your blog for helpful eye candy. Your project might answer questions I run into like,"where does this go"? My basketcase 1973 R75/5 came to me in boxes & I work on it as I also do 2 other vintage bikes at the same time & as time allows. Having never fully taken down an airhead there are reassembly questions that will come about, I'm certain of that. FWIW, my frame will get KBS "Black Top"satin black chassis paint based on quality of the paint,cost(the paints pricey-I'm the cheap part) & the fact that I do it in my shop & not a send out as is powder coating. I know many use powder coat for bike frames but I see many failures of powder coats on commercial applications so it's not for me. I read a coatings engr's comments on another site that made the point that it's simply another way of coating cure,i.e., heat vs. solvent. I have my fenders & tank ready for primer now. The headlight bucket is sitting on a workbench while I try to decide whats the best way to repaint it and not suffer too much trauma to get the wire jungle back inside! I'm leaning toward a "leave it mostly wired and mask off" approach. I'm doing my stripes with 3M fineline striping tape where you "peel away the white line areas" and have striping paint and brush to fill in stripes. I'll "finish the end" of each stripe with a flourish to suggest that it's a hand applied stripe as that's about as close to a hand striper as I'll ever be.

[brook.reams]

kantuckid,

Thanks for looking and sharing about frame painting. What attracted me to powder coating is the ability to cover round tube completely and to have a hard finish. I've spray painted them and never seem to get the uniformity I'm after ( read that, missed areas).

I'm very interested in your comment about 3M fineline striping. Can you provide a link to that product? I'm going to paint the bike myself (as I did on my R75/6 "S" replica project) and this time, I want to do painted pin stripes.

I hope some of my pictures help you on your project.

Best.
Brook.

[lmo1131]

Thanks for posting Brook. Excellent photo-journalism.

May I make a suggestion .... consider posting your blog "notices" in the same MOA topic. That way all of your information will be readily at hand in one location. Down the road, the only way to find this Tear Down article (for example) will be to use the Search feature ... which is not too specific with it's return information.

Shane Balkowitsch's Complete Restoration of BMW R75/5 into Cafe Racer project is a good example.

[brook.reams]

Thanks for posting Brook. Excellent photo-journalism.

May I make a suggestion .... consider posting your blog "notices" in the same MOA topic. That way all of your information will be readily at hand in one location. Down the road, the only way to find this Tear Down article (for example) will be to use the Search feature ... which is not too specific with it's return information.

Shane Balkowitsch's Complete Restoration of BMW R75/5 into Cafe Racer project is a good example.

Hi Lew,

Oh, indeed. That makes excellent sense. Thanks for that suggestion.

Best
Brook.

[brook.reams]

Hi Lew,

Oh, indeed. That makes excellent sense. Thanks for that suggestion.

Best
Brook.

Folks,

Per Lew's most excellent suggestion, this thread is now merged into this one so I can just add information on this project as I post it.
http://www.bmwmoa.org/forum/showthre...roject-Journal

Best.
Brook

[lmo1131]

Brook, before you send your frame off carefully inspect the passenger peg/muffler mounts. The "U" that the battery vent tube passes through creates an excellent stress riser; the worst case scenario is that a crack develops (where I've drawn a red line) ... check top and bottom. The right side on my '73 /5 was cracked, the left was not. I've purchased two frames in the past for projects; both had cracked brackets; one on both sides, one on one side only.

[kantuckid]

kantuckid,

Thanks for looking and sharing about frame painting. What attracted me to powder coating is the ability to cover round tube completely and to have a hard finish. I've spray painted them and never seem to get the uniformity I'm after ( read that, missed areas).

I'm very interested in your comment about 3M fineline striping. Can you provide a link to that product? I'm going to paint the bike myself (as I did on my R75/6 "S" replica project) and this time, I want to do painted pin stripes.

I hope some of my pictures help you on your project.

Best.
Brook.

You might take a look at a current thread on ADV under airheads that has a guy redoing the same bike. I commented on stripes & he tells his plan for same-I gave him a link too. Take a look at KBS website and their finishes. I've seen some paint brush frame jobs that were astounding using the Blacktop Chassis paint. It is tough stuff.

[lmo1131]

I've seen some paint brush frame jobs that were astounding using the Blacktop Chassis paint. It is tough stuff.

That reminds me, Interlux and Pettit make epoxy and urethane "topside" paints for marine application that give excellent brush finishes. For flat surfaces the process is call "roll and tip"; roll on the paint and follow up with a fine bristle brush to knock off the "tips" of the roller marks; generally a specific reducer is called for that slows the set time and allows the paint to flow out. On compound surfaces (like a frame tube) a brush alone does well.

[kantuckid]

Thanks for that tip! I'm going to check my frame closely based on the metal fatigue crack issue. I've been on other stuff so the frame is still in my barn.
On the KBS Blacktop paint: I was getting ready to paint my 1971 Honda project frame & when I opened the can it had hard sediment in the bottom that wouldn't incorporate into the mix. As the qt cost near $50, I called the tech line( nice guy too! offered to mail it but I was going that way to the AP store where I got it) & learned it was part of a bad batch/lot so just used black base coat on that bike but my new can of KBS still goes on the R75.
While painting is up for discussion in this thread I have a fender painting question: I have my fenders & tank sanded & ready for the epoxy primer I'm using & it's tough stuff. I really don't see a lot of appearance reason to paint the inside of the fenders as they obviously don't show much. The thing is, the holes were fatigue cracked a little bit and a couple holes needed redone as they were enlarged. That repair was made using epoxy & came out fine, probably stronger at the holes than originally as I reinforced each hole.
I was thinking that the epoxy primer would strengthen the fenders composite material just a bit but there was no paint there from the factory, so maybe being anal? How often are they painted inside?

[lmo1131]

How often are they painted inside?

Depends on how cold it gets in your neck of the woods this tima year .. .. ..

I'm a slug, I've painted my /5 four times since 1974, and I don't think I've ever painted the underside of the fenders. If it was intended to be a garage queen I might, but it's a road bike.

I had some stress cracking going on around the mounting holes as well. I chose to laminate a piece of 1.5oz. fiberglass cloth (using epoxy) onto the entire underside of both fenders, with a few extra pieces at the mounting holes, and turn signal housing boss. I didn't paint it then either.....

[kantuckid]

no paint "inside" is my real lean and this bike is being built to become a replacement for my oilhead and the trip bike. As for "how cold in my area" , I have maples tapped & the sap has run a little but not a good run yet, when it runs it's riding weather too!

[lmo1131]

I have maples tapped & the sap has run a little but not a good run yet, when it runs it's riding weather too!

Probably nothing to worry about, but nowadays ya jus' never know....

Maple Syrup Farm Mistaken for Meth Lab in Illinois.

[brook.reams]

Brook, before you send your frame off carefully inspect the passenger peg/muffler mounts. The "U" that the battery vent tube passes through creates an excellent stress riser; the worst case scenario is that a crack develops (where I've drawn a red line) ... check top and bottom. The right side on my '73 /5 was cracked, the left was not. I've purchased two frames in the past for projects; both had cracked brackets; one on both sides, one on one side only.

Lew,

Oh, that's a great suggestion. I added that to end of that section and included these photos.

[kantuckid]

Probably nothing to worry about, but nowadays ya jus' never know....

Maple Syrup Farm Mistaken for Meth Lab in Illinois.

The tree picture is not the greatest but it looks to me like they are tapping red maples, not sugar maples which have more "sugar" in the sap. I avoid the red ones as it takes me forever to boil the stuff down @ 40/1! Now back to bikes...