Inspiration, 1955 R50

[808Airhead]

John,I am friends with Mark,and he offered me that bike,but I already have 4 and passed. I am on Oahu,so are you I am assuming,and have rebuilt engines,transmissions,final drives,etc.,and I have every tool you need to do this stuff,even a engine/transmission stand. If you need help give me a e-mail and I will shoot you my #. My bikes run to perfection and have 1000's of reliable miles on them,so if you need any help give me a shout. If you want to install your crank,you are more than welcome to come over and borrow my engine stand and I can help walk you through it. I had a shop ream my valve guides and cut the seats,but installed new guides and rebuilt them myself.

[808Airhead]

My latest project was this 1951 R51/3 I just rebuilt the engine/rear drive,wheels/forks,etc. on . I RIDE them and restore them

[johnpst]

Aloha and Mahalo Thomas!

I may take you up on your offer. I've been considering my options. No matter what, the R50 will be a rider. It's a matter of how shiny and perfect. I think part of that decision has been made by the purchase of stainless bolt kits. My instructions to the painter, Hannibal on Sand Island, was to make it look like a well cared for original paint job. As you know, the paint was in pretty good condition. Now, do I blast the engine case to new or, hand clean it to a well cared for patina, which is my preference now. I'm getting distracted by stainless spokes and polishing up the rims. I still have time so, let's get on to the short stories of what was done before I started this post.

The dynamo. As I mentioned, when I got the bike running, the voltage regulator was not putting out adequate voltage. This story is a paragraph but, the actual job took a week of after hours study.

As you all know, the dynamo is a 6 volt x 45 watt direct current generator. In my world of power generation, the concept is, a magnetic field, relative motion, and conductors. Simple enough. The problem is, controlling that voltage so that it conducts enough current at the right voltage to light up the lamps. In today's semi-conductor world, all of that is effortless. In the 50's, it was a matter of mathematics and mechanics.

The original voltage regulator uses ohms law, springs, and contact points to work. Some of the power from the dynamo is diverted to the voltage regulator and powers a magnet. This magnet pulls an iron core attached to a lever which has contact points on it. The contact points carry electrons to the dynamo field. The cool part is, the current in the electromagnet builds a reverse current after a short time which turns the coil off. The field contacts open. This is repeated multiple times a second keeping just enough magnetic field in the dynamo to generate 6 volts up to 45 watts. Ingenious! Well, 60 years of riding has caused the insulation on the voltage regulator coils to leak allowing them to short out. This changes the magnetic field and therefore the ability to maintain the proper voltage for keeping the light on and charge the battery. Now, this can certainly be fixed by skilled craftsman like Tony at Sako Electric in Hawaii. The problem for me is, they were never that reliable to begin with and the time to rewind it correctlty would take a couple of days. There are other alternatives.

I purchased two solid state, modern regulators. A MZ ETZ 6V ELECTRONIC VOLTAGE REGULATOR and a TYP BMW R51/3 - 69S regulator. The MZ was poorly made with cold solder joints and would have had to be mounted away from the generator, like under the tank. I the TYP BMW. There was some confusion on the instructions but, a little work figuring it out and it works flawlessly and installes easily.

Problem solved. See the photos.

[808Airhead]

Hello John,I am actually using 2 of those same regulators in 2 of my bikes right now,they work perfectly. Be careful with Hannibal (from Psycledelics) he painted my R69S and did not do the striping correctly and I see "veins" p[opping up under the paint after only a couple years due to poor preparation. He also took longer than expected and when I told him I was taking it to "Cosmic airbrush",he then rushed the job out the door to get it back to me. I will never use him again.
On my R69S I used complete stainless kit and spokes,and SS spokes on all my bikes,well worth it. I have the wheel truing template for /2 and a truing stand,so if you lace them up,I can help you true them. I run my own auto repair business and am very busy,but summer is coming up and the waves are not as consistent so I have more free time for bikes. Where do you live? I can stop by one day with my R60/2 and give you some inspiration. I just rebuilt the engine and trans on that and runs and shifts better than the 17K original mile motor it was.

[johnpst]

Aloha all,

I restore bikes occasionally. Recently, I got the bug for a BSA Gold Star and during my research was inspired by a gentleman named Swan on the BSA Do The Ton Cafe Racer Forum; http://www.dotheton.com/forum/index.php?topic=20929.0.

Swan chronicled the journey he had with his DBD34 Gold Star, very similar to what I am working on. His description inspired me to share with you folks my 1955 R50 build. Swan has helped me to see options and resources in the BSA world which reminded me of some of the lessons I have learned about my BMW over time so, here goes.

This first post will be the longest since I've been at this for over a year now. A lot has happened. I'll cover the highlights and the important stuff here.

I have been a motorcycle fanatic for almost 50 years. I've ridden and raced just about everything with two wheels. As i age I'm getting nostalgic. Full disclosure, my commuting bike is a 2006 BMW R1200RT with the foot pegs ground to nubs and as much ware on the sides of the tires as on the center. Last year, I ran into an ad for a not running 1955 BMW R50 with Earles Forks. It brought me back to 1974 and my riding buddy Scott. We spend some quality time in Topanga Canyon, him on his R60 and me on my K550F. I met a business owner entrepreneur named Mark who had purchased the bike a couple of years before. The bike just stopped running and he didn't have time to get it running. We talked about politics, business, and motorcycles. He agreed to a reasonable settlement from his asking prices and I loaded the bike in my pickup truck, wife and dog riding shotgun.

The VIN is very near the beginning of the 1955 production run. Numbers all match and the bike was complete, as far as I could tell. My plan? Get it running and ride it of course. Problem? The engine was seized. After sticking a borescope in the cylinders, the right side was rusted solid. I pulled the pan and dug through with a magnet and visually inspected the rest of the bike and found nothing besides the stuck slug on the right side. That's where you all come in. I found VBMO and started reading.

First job was to get the piston unstuck. I fill the cylinder with WD40 and ATF and left the bike sitting for a week. After the week was up, I tried to kick the bike over. No good. I tried bump starting the bike. No good. DO NOT DO THIS. More on bump starting a press fit crankshaft later but, if your engine is stuck, do not force it any harder than the kick starter will allow.

I went about pulling the heads to inspect further. The bike had been apart before. The pistons were not original but, they were original 68 mm size though. Good! Minimal potential for having to replace expensive parts. The right side piston took some persuasion to get moving. About two weeks of soaking, heating, and mechanical agitation. I finally got it loose. Yeehaw! I measured everthing up, I honed the cylinders, bought new rings and reassembled. After going though the ignition and fuel system I was able to get the bike running. No real drama. In riding the bike I found the rolling chassis pretty good and the engine with NO power. The transmission shifted as smoothly as I though it should. The lack of power was really an issue. I pulled the plugs and check compression. 65 psig. Hmmm? I added some oil to the cylinders and checked again. No real change. I did a leak down test. The valves and rings (not unexpected after honing the cylinders) were leaking like crazy. All else thing being what they were, a top end and piston oversize seemed in order.

Here's where some drama came in. I did my due diligence and chose a shop in California to help me with the top end. We spoke on the phone, swapped e-mails, and agreed that he could do the work. After providing a specification as to how I want the work done (I'm an engineer and work on large scale jet engines for power industry. I provide specifications for everything.) the one question I did not ask was, how long this shop would have my parts. In my business I give daily updates on progress, with specific findings. I thought at least weekly would be reasonable for doing what I consider to be 10th grade auto-shop work when I went to school. I specifically looked for folks who had experience with these bikes because there are critical dimensions that only experience will know to check. Reading any reliable tech manual will get it done but, there's no replacement for experience. I prompted every week for an update. I would get answers about cleaning and installation before I got messages about disassembly. In other words, the vendor was BSing me. Bottom line was, the question I didn't ask was, how long it would take. it took 6 months to disassemble, clean, inspect, install new guides, replace the seats, and bore and hone two cylinders. The vendor started giving me excuses that he couldn't find springs and keepers. It took me twenty minutes to located some and sent them to him. I paid $700.00 more than we estimated plus I bought the valve gear because he "couldn't find any". Lesson? Don't be fooled by Facebook pages with great story's about the 90 year old mentor and friend teaching the old ways. My cylinders were not to specification. They were dirty when I received them which holidays in the paint. ring gaps were incorrect, valve springs were larger diameter than OEM and did not fit as designed. In the end, I had to rebuild the heads. The machine work on the guides was correctly done and the seats were properly installed. I can only assume he had someone else do that work. Buyer beware! Any vendor that tells you they do not have time to document their work is not worth partnering up with.

That was the only bad experience so, I'll move on.

I got the top end installed and got the bike running again. Yeehaw again! Much better After a good tune up I started the break-in period. Changed the oil a couple of times in the first 100 miles just to be sure (Valvoline VR-1). I rode the bike to work and got the oohs and awes of my fellow gear heads. The suspension was a little mushy and the tires were over 10 years old so, It was time to do "the little things" to make the bike a safe rider. I also found the voltage regulator was not working correctly. I found the coil insulation was old and leaking which caused shorted wingdings, changing the voltage the regulator would hold to 12.8. No enough to ride across country but, fine for a day rider, until I decided to cruise the beach one night. It was unnerving to ride at night when the headlamp dimmed every time the bike was at a stop. I bought a new VR (see other post for that story). After cleaning and testing, the dynamo worked fine. Problem solved.

Tires were changed, rims were cleaned, and the brakes freshened up. I bought new liners and riveted them in myself. I chucked up the wheels in one of my mills at work and clean up the brakes. No drama. Bike stops like it should, not well. Over the next week I found multiple minor things to adjust and replace. The speedometer warbled like I remember the magnetic styles of my childhood so, off it came for a cleaning and inspection. No drama. The mileage ticker however clicks away at at least twice the actual mileage. I'll deal with that later. I changed the headlamp with a halogen bulb. Much improved. Similarly, I replaced the rear brake lamp with LED drop in replacement. Again, great improvement.

After a week of tinkering and riding to work, 5 miles away, a knocking began in the lower end. Hmmm? I did just do a top end. Maybe the wrist (gudgen) pin, which was 0.0015" smaller than the bushing (I though I'd fix it later when I installed it) was the problem. In steps Dan Niener of CycleWorks. Dan helped me with a bushing replacement tool. "Off With Her Head". The tool works perfectly. I measured everything up and found it to be right were it was on reassembly a week earlier but, replaced the bushing anyway since I bought the tool and it was apart. Curious. If nothing changed, then where is the noise coming from.

I put it all back together and found the noise was still there. Hmmm? I laid the bike up and ran it weekly to keep everything oiled and help troubleshoot. I used screwdrivers and stethoscopes to try and isolate where the sound was coming from. The knocking was intermittent, not like a rod bearing. I could not isolate where the sound was coming from. Cam? Nose? Crank? I took run-out on both shafts and found the nose of the crank to have 0.025 run out. This is well out of spec but, the spec if for the crankshaft isolated on a mandrel. Hmmm? After 6 months of reading and thinking, I finally pulled the engine apart. CycleWorks has provided me with the Many In One tool which works as described. When I got the timing cover off I could see that the oil pump gear was torn up. Probably salvageable but, more on that later. Further inspection found the nose bearing race had grenaded. The race bits were sitting in the bottom of the timing cover. Now I'm thinking, ok, now I can go with the original plan. Replace the bearing, get back on the road and restore later. Luckily, I thought better of that idea. I pulled the whole thing apart and found the rear bearing grenaded. Measuring the connecting rods found the bearings to be out of spec. I called Dan at CycleWorks and cried on his shoulder a bit about my last experience with a vendor and had him estimate looking at the crankshaft. He found that the webs had slipped causing the run-out to be excessive. Remember, I told you I'd get back to not forcing a seized engine any harder than the kick start will allow. Apparently, the force of bump starting was enough to cause the crankshaft to deviate resulting in taking a 60+ year old crankshaft and 40+ year old bearings and shredding the races.

The crank will be restored to factory specs. the connecting rods will be honed and larger bearings installed to tighten them up to the crank pins. The flywheel will be lightened up to help with shifting.

I've completely disassembled the bike for restoration now. The tank, fenders and miscellaneous painted bits are at the painter now. All proper BMW Avus Black paint and white pin striping specifications have been provided. I still have some disassembly work to do before getting the frame to the powder coating shop. My daughter and granddaughter are in town so, it will be a couple of weeks before anything changes.

So, now we're all caught up. Here's some photos to walk through the progress. See ya in a couple of weeks.

John

[JDL]

Hi John,

I will follow your progress. It looks like after a not so good start things are falling into place. I'm curious as to who is that first engine builder. Whenever I hear stories like that I take a mental note and try to avoid certain vendors. However, if no names are mentioned it's impossible to avoid them.

Thanks,

JDL

[Slash2]

808, Why aren't you my neighbor?

[808Airhead]

/2,I wish we were ALL neighbors! LOL
John,I just checked my message box,the last message in there was from Darryl Richman in 2011,lol. There are no messages from you in there,try again or my e-mail taivw@hotmail.com

[schrader7032]

I believe there is a problem with the internal messaging system. Best to use emails for contact.

[808Airhead]

Mystery solved!! That is why I never replied to your message John,I never got it!!