1973 BMW R75/5: Fork Rebuild and Refinish

I just posted a new web page on rebuilding and refinishing the fork tubes. You can see this entry on the right hand column and can access it by clicking the 31 BMW R75/5 Fork Rebuild link.

I’m labeling the web pages for this project with the number BMW uses to identify major sub-systems of the R75/5 so you can easily correlate procedures with parts.  You can see the numbers on Hucky’s /5 parts page.

Here are some before and after pictures.

Front Forks with Wiring Harness Removed

Starting Out with Wheel and Fender Removed

Fork slider details

Grungy Fork Slider Removed

After Rebuild & Polishing

Final Product, Rebuilt and Refinished

1973 BMW R75/5: Bing Carburetor Restoration

Over the Christmas holiday, I restored the Bing carburetors. A restoration is a bit more work than a rebuild since the goal is to restore the finish to factory new condition as well as replace worn parts and all the O-rings and gaskets. Much of the time invested is in cleaning and polishing all the parts. You can access the web page about this using the this link:

which is also on the list of pages to the right. I’m using BMW parts subsystem numbers for the rebuild blogs so you can correlate the procedures with the parts.  You can see the numbers on Hucky’s R75/5 parts ordering page.

Here are some before and after pictures.

Carburetor in Decent Shape

Before-Barn Fresh

Before Soak, After Soak

Outside, Left No Cleaning, Right After Parts Washer

Before Soak, After Soak

Inside, Left No Cleaning, Right After Parts Washer

Cleaned and Polished, Outside View

Outside, Rebuilt and Restored

Cleaned and Polished, Inside View

Inside, Rebuilt and Restored

Cleaned & Polished - Top View

Top, Rebuilt and Restored

1973 BMW R75/5: Planning the Rebuild

Before starting a project and spending money, I try to take an inventory of the bike’s condition and develop a plan and budget. Usually, for a bike this old, I can plan on replacing everything that’s rubber, all the control cables, and renew all the filters. Since my wife has owned this bike since 1978 when I bought it for her as a wedding present, I have a pretty good idea of how it has been maintained and any major problems. Overall, the bike is in good condition for its 40-year age and 97,500 miles.

I took a number of pictures to document the “before” condition and to help with an initial parts list for the project.  I also removed the front fender, gas tank and seat to get a better look at the frame and chrome to better see the condition.

This is the high-level work plan  I came up with.

  • Replace all rubber parts
  • Remove all cables, tachometer and speedometer cables
  • Remove fairing
  • Remove tank, side covers and fenders
  • Rebuild petcocks and polish
  • Remove front wheel
  • Clean and polish front wheel
  • Grease front wheel bearings
  • Inspect brake shoes, replace if necessary
  • Rebuild front forks
  • Replace steering head bearings
  • Remove carburetors
  • Rebuild carburetors, clean and polish
  • Remove heads and cylinders, exhaust
  • Clean and polish exhaust header
  • Replace mufflers and cross over pipe
  • Bead blast heads, cylinders, valve covers
  • Rebuild heads with valves, seats, seals and springs
  • Replace piston rings and hone cylinder
  • Remove rear wheel
  • Clean and polish rear wheel and hub
  • Grease rear wheel bearings
  • Inspect brake shoes, replace if needed
  • Remove shocks
  • Clean and polish shocks
  • Remove battery box
  • Remove turn signals
  • Clean and polish turn signals
  • Remove rear frame
  • Remove rear drive
  • Remove transmission and clean
  • Grease drive shaft splines
  • Remove engine and clean
  • Remove all electrics
  • Remove wiring harness
  • Strip paint from frame, rear frame, rear drive, battery box, fairing bracket, handlebar controls
  • Powder coat frame, rear frame, rear drive, battery box, fairing bracket, handle bar controls
  • Strip faring paint, repair dings and replace chrome edging and windscreen gasket and  wiring harness plug
  • Strip paint from fenders, tank, side covers
  • Paint fenders, tank, side covers, fairing
  • Reassemble frame, wiring harness and electrics
  • Mount engine and transmission in frame
  • Reassemble rear frame
  • Reassemble swing arm
  • Reassemble shocks
  • Reassemble battery box
  • Reassemble cylinders and heads
  • Reassemble carburetors
  • Reassemble exhaust and mufflers
  • reassemble handlebars and controls
  • Replace all control cables, speedometer and  tachometer cables
  • Mount new tires and tubes
  • Assemble fenders
  • Replace battery
  • Assemble wheels
  • Assemble tank on frame

Here’s some of the “before” pictures.

Carburetor in Decent Shape

Left Carburetor

.Carb & shaft drive gunge

Right Carburetor and Drive Shaft Gunge

Petcock leaks

Petcock Leaks

.Points cover grunge

Possible Points Seal Leak

.Barn straw and leaks

Push rod seal leaks

..40 yr old foot peg rubber

40 Year Old Foot Peg Rubber Shot

.40 yr old foot peg rubber

Shot Foot Peg Rubber and Brake Pedal Rust

 

.Steering head gunge

Fork leaks and Top Clamp Gunge

.Brake hub grunge

Front Hub and Fork Gunge

.Front rim gunge

Front Rim Grunge

.Windjammer II dings

Windjammer II Painted to Match with Chips

.Rebuilt Vetter fairing bracket

Faring Bracket and Frame Rust

.Tank scratches

Tank Scratches and Dings

.Faring & fender off

Wrong Fork Boots & Frame Chips

.Fender dings

Front Fender Damage

.Pin stripe closeup

Front Fender Pin Stripe Detail

.Faring braket rust

Frame Tube Rust and Paint Dings

.Paint and rust

Frame Rust, Dings and Clutch Cable

Battery Box Corrosion

Battery Box Corrosion

Battery Box Corrosion

 

 

1973 BMW R75/5: Starting to Rebuild

Here is the link to the web page that I will use for documenting this rebuild. It’s a two owner (my wife being the second), 97,500 mile, 40 year old bike that’s been stored in a friend’s barn for the past six years. I’ll post some blogs on the project as I go.

I’ll also keep a photo scrap book here  –> Project Progress Photos

Silver Ghost Restoration-Epilog

Here’s a short video of the startup of the Silver Ghost on Halloween night 2010.

And, you can look at a summary of before, during and after photos of the build here and see the entire set of photos here.

Lessons Learned

Before I started, a blog I read said “Start from the inside and work your way out.” .  The logic made sense to me in developing the budget.  I estimated the cost for the frame straightening and fork tube replacement I knew were required.  This was the most expensive work I had done, and ended up costing about 50% more than the estimate.

After that was done, I prioritized the other “must do” work. I had the top end inspected and got cost estimates for repairing the broken fin on one head.  The estimates ranged from over $100 to about $15.  I took the $15 bid from Randy Long even though shipping to Pennsylvania and back cost me $25.  When he got the head, we talked and he pointed out the valves were past their service life.  So he got both heads and I had him replace the seats, valve guides, springs and exhaust valves.  Randy does great work and is willing to share his knowledge.

I priced out the carburetor repair and rebuilding, replacing the rear sub-frame since I knew it was cracked, and a new exhaust system as the original I had held on to was in bad shape.

I developed an estimating spreadsheet to forecast the costs and updated the total with actual cost when I bought parts.  Its a good idea to identify “must” from “nice” to have parts.  Get all the must have parts priced and paid for and then work on the nice to have sourcing new and used parts (eBay, BMW MOA forum, Craig’s List, Vintage BMW Motorcycle Owners group, and the BMW Internet Riders forum).

Optional parts included a used cast “snowflake” rear wheel to match the front one I bought in 1982, a used R90/S fairing, new electronic ignition, used bar end mirrors, and used battery tray.  Checking the on-line used markets and eBay for about a month turned up deals on many of these parts, so I spent the money.  With eBay, I only had one part with some disapointment, the cast snowflake wheel which had a dig in the rim.  But, I found a local company, Woody’s Wheel Works, who could pound it out.

Painting was the shock as I originally planned to have it professionally painted.  But, after multiple bids over $2,000, I called a friend who rebuilds classic British bikes for some advice.  He talked me into the “growth experience” of painting the bike myself.  He had the equipment, advice and encouragement.  I had to do the rest.  It took me 3 times as long to complete the painting as I had estimated.  The material cost doubled when I had paint failures and had to buy another paint kit from Holt BMW.  But, the education and satisfaction were priceless.  It was the memorable experience of the project and even though I got very frustrated and discouraged more than once.  As Brian says, “Endeavor to Persevere”.  And, “There’s nothing about painting you can’t fix with sand paper and more paint.  You can’t break anything.”

My original budget was more than the blue book value of the bike, and that is typical for a rebuild, or in my case, a build of an R90S cafe racer replica.  I kept detailed records of all costs.  The paint preparation (primer, sand paper), solvents, cleaners, shop supplies cost much more than I had estimated.  Don’t over look that in your budget.  In the future, I’d put in a 5% shop supplies budget and estimate primer cost at 30% of the paint cost.  The final cost exceeded the budget by 60%.  Plan accordingly.

Finally, there is practical value in figuring out how to overcome the “cussedness of inanimate objects”, not at the time, of course, but in retrospect  :-).   I’m reminded of Robert Pirseg’s book, Zen and the Art of Motorcycle Maintenance,  “The real motorcycle you are working on is yourself”.  If that is true doing routine maintenance, then doing a rebuild of a bike means you are rebuilding yourself.

Resources

The web is a great resource for advice, parts, options and ideas.  I found a large amount of information, resources and “How To” advice for rebuilding bikes in general and BMW in particular.  I  asked questions on various forums and always seemed to find someone who had the tid bit I was looking for.  The available knowledge and willingness of folks to share what they know make taking on a project of this scale doable.  All you have to do is search and ask, and you can learn just about anything you don’t know.  I compiled a list of resources I found here.

I found Max BMW’s on-line parts fiche a reliable tool for cost estimating as well as other on-line suppliers of parts for classic BMWs (Benchmark, Rephyche, and Hucky’s).  My local dealer, BMW of Denver met or beat most of those prices but I did some business with internet sellers as well.

In particular, Clem Cykowski at BMW of Denver, Kent at Holt BMW and the kind folks at The Bing Agency were particularly helpful and supportive.  And of course, my friend Brian House, who encouraged me to learn how to paint motorcycles and lent me his equipment was a great resource of tips, advice and wisdom.

Tips for Those Who Follow After Me

In no particular order, here is my list of tips when doing a project like this.

  • You can do this work with simple tools in your own garage.
  • Clean out a work area and keep it clean
  • Newspaper is a your friend.  Keep it handy, cover your work bench with it, change it often.
  • Shop towels on the roll are very handy.  Buy a half-dozen rolls.  They are always “clean” when you need them.
  • Take pictures as you take things apart.  You will not remember how everything goes together in a year.
  • Bag parts as you remove them in plastic zip lock bags and label them with what they are (front fender, shocks, etc.)
  • Use boxes to hold parts bags for major subsystems.  I put all electrical parts in a box, all engine parts in a box, etc.
  • Keep a list of “to buy” parts as you remove them.
  • Assume you will buy all new rubber parts.
  • Develop a “to do” list for work you have to do and think about the best sequence to do it in.  You will save a lot time in end and avoid “redos”.
  • Monitor your patience, attitude and energy level.  When you aren’t feeling focused, confident, or happy, stop working.  You’ll just screw something up, usually something expensive or hard to find.
  • There is no rush.  Take your time and the stress goes away.
  • The fun comes from doing, thinking, planning and overcoming the “Oh Shit” that is inevitable.  Relax, have a beer, tomorrow’s another day.  If you aren’t in the mood, the bike is not going to go anywhere.
  • When you get stuck and don’t know how to get a part on, or figure out how to fix a mistake, clean the work bench.  You can control that, and in the process, solutions will come to mind if you will just be quiet enough to let them suggest themselves.

Painting

  • Sand paper and its proper use are critical to a nice paint job.
  • Preparation will take 80% of the time for painting.
  • Sand the last coat with a finer paper than the previous coat.  For 3 coats of primer, 320 grit, 400 grit, 600 grit.
  • If you are painting base coats with silver or black, add a fourth coat of primer and sand at 1500 grit.
  • Clear coat looks very shiny when it goes on, but it has to be sanded to remove the “orange peel” and dust motes.  Use no coarser grit than 2000 and finish with 2500 grit.  Then you can buff it out with scratch remover.
  • You can’t really ruin anything when painting.  If you make a mistake, grab the sandpaper and erase it.  Worse case, paint it again.