11 BMW 1973 R75/5 Refinish Cylinders and Refinish & Rebuild Heads

Here are some pictures of the engine as I did the tear down to the frame. I had cleaned it with solvent-based engine cleaner to get the top layer of built up oil and grease off it before I brought it into the work shop.

Carb removed

Carburetor’s Removed

Cylinder off

Cylinders and Heads Removed

Ready For  Engine Removal

Ready For Engine Removal

Another use for Park-n-Move Dolly as Engine Stand

Another Use for Park-n-Move Dolly as an Engine Stand

Cylinder, Valve Cover & Exhaust Nut Bead Blasting

There is a local shop in Arvada, CO, Roadies Performance, that does bead blasting for me.  They build customer Harley’s and are great folks.  If I can, I like to spend some of the money for a rebuild in the local community. I took the cylinders, valve covers and exhaust nuts for blasting and got them back in a couple of days. It cost $83.00.

Cylinders, Valve Covers and Exhaust Nuts Ready for Bead Blasting

Cylinders, Valve Covers and Exhaust Nuts Ready for Bead Blasting

I scribed an “L” and “R” on the top of the cylinders. Here’s the final product I got back.

Bead Blasted Cylinders, Valve Covers and Exahaust Nuts

Bead Blasted Cylinders, Valve Covers and Exahaust Nuts

Good as new.

Head Rebuild

I sent the heads to Randy Long at Long’s Mechanical Services in Pennsylvania for inspection and repair. I figured the exhaust seats would need to be replaced and I asked for new valves, seats and guides.

I don’t believe Randy has a web site and I’m not sure he has a business Email address, so I call him when I need some work done. He’s been building heads for quite awhile and works on BMW, Harley and British bike heads. I think he got started when he was racing a Harley drag bike. He rides BMW iron and has been out to Colorado a couple of times riding, so I always enjoy chatting with him on the phone.

Randy Long
Longs Mechanical Services
74 Risbon Road, Honeybrook, PA 19344
(610) 286-5870

I just got the heads back from Randy.  Total cost was $490.  Here they are good as new again.

Rebuilt Heads

Rebuilt Heads by Randy Long

New Springs, Keepers, Valve Gudes

New Springs, Keepers and Valve Guides

New Valves and Exhaust Seats

New Valves, New Exhaust Seats and Decarbonized

Air Box Clean Up

I cleaned and polished the air box covers as shown below; before and after.

Airbox Covers, Before Polish & After

Air Box Covers, Before & After

As noted in other posts, I start by cleaning in my parts washer with a tooth brush and soft stiff nylon bristle brush to get as much oil and grease off the parts as I can. I use Scotch Brite pads with AutoSol aluminum cleaner to  get oxidation and baked on crud out of the rough casting. Then I use “00” steel wool with more aluminum cleaner until I get a nice luster. I follow this up with AutoSol aluminum paste polish to add some shine and finally, I finish with AutoSol Aluminum Protective Oil to help keep things looking new for awhile.


7 thoughts on “11 BMW 1973 R75/5 Refinish Cylinders and Refinish & Rebuild Heads

  1. Pingback: 1973 BMW R75/5: Renewing Cylinders, Valve Covers and Heads. | Motorcycles & Other Musings

  2. This is exactly what I was looking for!
    Thanks very much!
    Presently I have via Tom Cutter a set of R65 heads at Randy Longs which were re-done by Ted Porter for dual plugging.
    Looking forward to get them back.
    Paul K V Lissberg, Singapore

    • Hi Paul,

      I think Randy does very nice work. BTW, your address show Singapore. Back in 1978-1980 I consulted on two office buildings there, The Standard Chartered Bank and what is now Raffles Square.

      All the best on your R65.


  3. Brook,

    Have you powder coated or protected aluminum following bead blasting with a permanent finish? I’m not sure with an air cooled engine if a power coat finish would retain excessive heat and see that no one in forum babel has any actual data.

    I’m in Ohio so spring road grime will make a mess of all that work!

    Mike ’70 75/5

    • Hi Mike,

      I’ve not powder coated any engine parts. I have painted the engine cylinders with high temperature engine paint as BMW did on the R90S.

      I would not try powder coat on engine parts.

      I have used AutoSol aluminum protective spray on cleaned engine cases. I’m also trying Boeshield T9 to see how it well it works. It has been recommended to slow the darkening of the finish.

      In the end, dirt and grime are inevitable. 🙂

      I hope this helps.


  4. Dear Brook

    One more question regarding rocker arm shaft/axle which will insert bush, rocker arm and thrust ring, base on this that thrust ring should be free play into rocker arm shaft but mine was stuck with rocker arm shaft and cannot removed.

    any idea why it happened and shall I need replaced all shaft and ring when I rebuild my bike? It may one of reason to caused abnormal noise from cylinder head as discussed days ago.

    Please advise

    • Calvin,

      I believe the rocker arm assembly on the early R75/5 has a bronze bearing. If the rocker shaft can not be removed easily by hand, then bronze bearing has been damaged. This could be caused by lack of oil flow to the rocker. This oil flows inside the passage around the top cylinder studs. Or something else may have happened to damage them.

      You will need to replace the rocker, and the rocker shaft.

      I hope this helps.


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