This continues the the excursion.
In Part 1 of this excursion I reflected back on the Book Zen and the Art of Motorcycle Maintenance of Robert Pirsig and how I identify with the Classical approach he is outlining in the book as an opposing pole of the Romantic approach towards problem solving. Pirsig had these two categories for people and elaborated on the differences in how they would approach motorcycle maintenance and problem solving in general. After reading the book when I was a teenager I had occasionally re-visited parts of the book, always thinking that I should read the whole book again at some time. I will now do, because I had an experience with motorcycle repair that initially stunned me but for which I then found an explanation in Pirsig’s concepts.
Recently, after always maintaining, repairing and restoring motorcycles all by myself and never bringing them to a shop – as Pirsig suggested in his book – I broke with this habit for the first time in 39 years. I brought my 1971 BMW to a local motorcycle shop. And it did not work out for me. Many others would have been satisfied with the outcome, for me it was pretty much a disaster. When thinking about it afterwards Pirsig’s elaborations about the Metaphysics of Quality came back into my memories, slowly first and then faster, with increasing clarity. In addition to the underlying theme of taking care of the motorcycle maintenance myself and not trusting others with it, the series of events that were supposed to be just the changing of a set of cylinders and pistons turned out to be a clear collision of Pirsig’s Classic and Romantic views of the world.
To set the scene, a few words about the background are needed in case you have not read the first part of this excursion: My first motorcycle ever, a Honda CB125J, which I had bought brand new, I brought to the shop for servicing twice. Then curiosity took over and I started doing it myself. This became a habit and I maintained it over the years. I also took four motorbikes completely apart and restored them to brand new condition. A BMW R25/2 with Steib LS200 side car, a Honda XL185, a Honda Dax ST70 and the BMW R75/5, which is the subject of this story. In these endeavors I only bought components to a repair shop that I could not fix myself, like the crankshaft, a gearbox and other parts where you need special tools I don’t have. The said BMW R75/5 was in quite a pitiful state when I acquired it and I stripped it down to the frame and restored it to original condition all with genuine parts, so internally it is basically a new bike with around 5,000 km on the clock. The only modifications I made was increasing the engine size by replacing the 750ccm cylinders with 1,000 ccm cylinders and pistons using the Siebenrock Power Kit, fitting a 5 gear gearbox to replace the 4 gear box of the original /5 series, installing a stronger starter motor to overcome the higher compression of the Power Kit, and installing a racing alternator from Silent Hektik with more power to compensate for poor battery charging at lower revs caused by the higher torque the Power Kit delivers. The cylinder heads were overhauled by a BMW accredited shop in Germany. All internal parts are new, or better 5,000 km old, and the bike was running nicely, until a week ago.
The next two paragraphs are a bit technical, so readers who are not interested in these details can skip them. The compression measured recently before the backwards conversion showed 10.35 bar on the left and 9.8 bar on the right, the Siebenrock kit is specified with 1:10.4 so not too bad. The original configuration with the BMW parts should have a compression ratio of 1:9. The Siebenrock kit increased the power from 50 hp for the stock configuration to around 60 hp after the kit was mounted, but the main difference was a huge increase in torque. I hardly had to shift gears anymore.
In conversations with other /5 owners I recently got a bit worried, they claimed that the motor housing of the /5 series is a bit weak and that the housing sometimes cracked under high load. The BMW accredited workshop in Bavaria, who had replaced the crankshaft bearings during my restoration, had said the same and had tested my housing for cracks. Given the increased power of my bike, I became quite worried and this worry accompanied me on every trip. Not much fun to ride a bike and expect the engine case to crack any time. So I decided to convert the bike back to 750 ccm. I still had the old cylinders and pistons in original size, there were some small spots of wear from corrosion at the lower cylinder surface. The pistons were worn and unusable. So I ordered a forged, high performance piston set with the first oversize from Motoren Israel in Germany and took them back to the Philippines after the home leave in 2017. Original bore size is 82 mm, first oversize 82.5 mm and second oversize 83mm.
So I asked one of the top motorcycle restorer in the country whether he can bore and hone cylinders and he said he could. I brought the old cylinders and the new performance pistons to him and he suggested to have the next oversize due to the damaged spots in the cylinder. I did not think the damage to be so deep that removing 0.25 mm of material would not have addressed it, but I did not want to question the expert, so I went back and ordered the second oversize pistons. They arrived per courier in the Philippines a few weeks later. I then brought them to the shop.
After some business travel I got notice from the shop that the cylinders were ready and the shop offered also to mount them. Recently I have been quite busy with work. I also have other personal projects, we built a sailboat for the family and are still in the process of optimizing it. And there are many other things to do at the end of the year. Changing the cylinders is quite straightforward, it takes me two hours to do it myself. And there is not too much that can be done wrong, so I decided to safe me a weekend day for a change and bring the bike to the shop and let them do the conversion. I also had some small jobs that needed to be done, I had lost the steering damper and that needed replacement, and I had a luggage rack that needed some customization to be fitted. The left carburetor was also often leaking fuel, an issue that I had not been able to address successfully even after a full re-built of the carburetors with all now parts. So it made sense to me to bring the motorbike to the shop anyway and have checked wether the float needle valve could be re-worked.
Which I did, also verbally leaving detailed instructions about what jobs needed to be done. After returning home I also sent those instruction in Facebook Messenger, just to be sure that everything is noted and addresses. Being a Classical person I had left as much technical detail as possible in order to make sure that they understood the bike and its history as good as possible. I also had explained the additional starter button I had installed on the left side behind the battery side cover because the starter switch at the handle bar had a bad contact which let the starter click in fast succession when pressed but did not turn over the engine. The fact that the added button started the engine without problems profs that the starter motor is not the problem, but the switch at the handle bar is. I tried to make that as clear as possible to the mechanics, since I was expecting that they might want to find the cause of the problem and tinker with the bike more than necessary. I also told them that I had already ordered a new switch, basically telling them to leave the starter alone. In addition I told the owner that the bike might not look as nice as the one he restores, but that for me first priority was performance and function, and not looks. When I left I felt that everything was fine.
The shop owner had offered to change the cylinders on the spot while I was waiting, I said there is no rush, I did not want to stay the whole day in the workshop, then I could also have done the job myself. After all, my aim was to safe myself some time. This turned out to be a mistake, being there would have prevented many of the issues that came up later.
The shop has the habit to send photos of every step of work, according to the owner this is done to be completely transparent about what they do. The first set of photos I got via Facebook showed the cylinders removed, alternator cover removed, and, to my surprise, the top engine cover removed and the starter motor removed as well. I got deeply worried. I had not asked them to work on the starter motor, instead I had made it a point to leave the starter alone. I had even explained the cause of the electrical problem and specifically said that I don’t want work to be done on it. Bikes are emotional things. Later I told friends that at the moment when I saw the pictures, I felt as if I had left my wife or girlfriend with a friend for dinner and then later found out that the friend not only had her in the dining room but also took her to the bedroom. Nothing might have happened in the bedroom, but mistrust was seeded already. Not good. I immediately send a text appreciating the progress on the cylinders but asking why the starter motor was removed. The response was that it was removed for cleaning as an extra service. The first clash of the Classical vs the Romantic view:
Classical (me): Analysis of the problem, identify cause of the problem, conclusion that there is nothing wrong with the starter motor. Never change a running system. Every time screws are removed they cause a bit of wear, and there is the danger of damaging the thread in the soft aluminum of the housing. Therefore, leave well functioning things alone.
Romantic: We provide an extra service to the customer, which will be appreciated because we go the extra mile.
I had not gotten so far yet in the understanding of the process of analyzing what was going on, I was just deeply uncomfortable, worried, but I decided to ignore it. After all, he is the expert and restores and repairs hundreds of bikes every year.
Later some pictures of the cylinder head with valves disassembled and the question whether the valves have been changed arrived in my Facebook messenger. Alarm bells rang again. I had not asked them to overhaul the cylinder heads. This had been done around 3,000 km ago by a BMW licensed shop in Olching, Germany. Valves, valve seats, and springs were replaced back then. The only thing the cylinder heads need are a conversion to be used with lead free fuel, which I intend to do at some time.
Classical: The bike ran well when I brought it. So on principle it should be OK. Measured compression was high and quite even, so there should be no problem with the cylinder heads, they both worked well and evenly with the Siebenrock cylinder. So just the pistons and cylinders need to be changed. Never change a running system.
Romantic: (I have to pass here, No idea what the motivation was to disassemble the cylinder heads. But probably also the extra service provided to customers)
Two weeks later, after returning from another overseas business trip I got another set of photos and a report that the steering damper was fixed and the luggage rack mounted, a small bracket had to be manufactured for it. They had mounted the cylinders too and were doing some tests. Good news.
A bit later came a text saying that there was some smoke from the exhausts indicating that oil is burned, and that they would recommend to install oil seals on the valve shafts. Supposedly he has done that for 5-6 customers already and they are all satisfied.
Classical: There was no visible oil burning when I brought the bike. I had it at emission testing center around 6 months ago, emissions are well within limits. With this type of engine there is always a bit of oil burning in particular when the bike was parked on the side stand. That is normal. Given that these engines usually last 100,000 km before a major overhaul is needed there is something wrong here if oil is burning. Since I did not observe smoke before brining the bike to the shop, this must be caused by the recent modifications. First thought, oil burning also happens when oil leaks between cylinder and piston, which could be caused by broken oil rings or by too much clearance. Did something go wrong with the boring? The fact that there was nothing wrong before supports this assumption.
Romantic: Visible oil, can be fixed using oil seals on valve shaft, this would take care of the leaking of oil into the combustion chamber, no more smoke seen, customer is happy.
This triggered some discussion, I also did an immediate inquiry on the 2-Ventiler Forum, a BMW online platform in which a lot of German owners and mechanics discuss technical topics. It also has an impressive technical database on the 2-valve models.
Classical: Based on previous performance and measurements this must be something introduced by the latest modifications. Either by the cylinder / piston system, or by disassembling the heads.
Romantic: There are some fine scratches on the valve shaft, it must leak oil.
Classical thoughts: What about measurements? Send the bore specifications for second oversize, asked whether the shop has the tools to measure to this resolution (0.01mm) exactly. (Response: We have a digital caliper). Oh no. Calipers have a resolution between 0.01 and 0.1mm and dimensional accuracy for more expensive calipers is usually not better than 0.02mm. With larger distance the accuracy goes down due to the tilting error. For measurement of the bore you need an internal measurement instrument. Does he mean that with “digital caliper”? What about calibration? The fact that a device is digital does only say something about the display, it does not say anything about accuracy. We have a digital moisture tester for rice that has 6% error but show moisture content in 0.1% steps. Not sure whether the shop knows those things.
Romantic: The valve shaft has scratches, must leak oil.
Classical thought: What about measuring the valve shaft and valve guide diameters and comparing it with the specs rather than talking about scratches?
Classical: I don’t really like the idea, it appears to be a quick fix to me. You cover up a possible problem with a short term solution and might run into problems later which you might not realize because the oil seal covers it up. If seals would make sense BMW would have designed the engine with oil seals.
Romantic: We don’t do quick fixes. Because of respect to the German engineers who designed the BMWs we always uses original parts and make no major modifications. For the oil seals, we have done that to many customers bikes already and it always eliminated the smoke. They are all happy with it.
At this stage I thought why not. Lets install the oil seals and if there is no smoke it is a positive effect, if there is smoke it is not the valves. I did ask about quantification, is there smoke only if the engine is cold after starting or also if the engine is hot? No response. Anyway, I give the go ahead. Then the responses from 2-Ventiler come in. A total of seven responses. Most of them advise against the seals. The engine is not designed for seals. One tried seals and said they are useless because of the very high temperature in the air-cooled head, the seals get hard and brittle very quickly. One says that oil seals are only needed in OHC engines with very short valve seats (makes sense to me), another one says that some oil is needed to lubricate the valve shafts (makes sense to me too, but another one says that is not the case). The bottom line is that I can not find any evidence of long term consequences of such modification.
Classical: Several people who have dealt with the matter technically advised against it. They cited technical reasons. To me it does not make sense to use the seals, if it would cover up wear that is developing and in the worst case could therefore cause some more major damage in the long run without sending alarm signs like increasing smoke levels that would help the understanding that there is something wrong. Oil seals are clearly a quick fix.
Romantic bottom line: No more oil in the exhaust, looks good. Other people were happy with it. We don’t do quick fixes. We respect the German Engineers.
I send him a follow-up note saying I don’t want the oil seals. Motor is assembled, so I tell him I will pick up the bike in two days on Saturday.
The next morning there is another set of pictures that shows the cylinder heads with oil seals installed. You need to remove the cylinder head to disassemble the valve springs, which gives access to the valve shafts, a necessity to install the seals. So they must have taken the cylinder heads off again. The message says there is no more smoke. I get really frustrated and angry. I specifically said I don’t want the seals. I have to do something else for a while to calm down before responding. I ask them to remove the seals. I don’t want them for the reasons I had explained before.
Classical: Citing all the own technical concerns, technical reasoning from other owners and mechanics, citing that BMW would have done it in later 2-valve models if it would make sense. Citing potential long term effects.
Romantic: Have done it for many users and they are all happy. Nobody has long term effects.
Classical: Analyzing this last statement, driving in the Philippines is different than what I am used to so I don’t use reports of Philippine drivers as reference. Here you never can go full speed, full throttle due to bad roads and the traffic. And it will take a long time to accumulate the mileage to see any long term effects. Probably years. All bikes I have ridden here in the Philippines that belonged to other local owners did by far not meet my standard for being technically sound. Most owners don’t mind or don’t notice it because they go slow, and they don’t know better. I want the bike as much as possible to original design specs, so that I can take it back to Germany and drive it there as I would with a bike with German history. And because that is just me. I don’t like to compromise on function and performance.
Romantic: Please come first and have a look at how it works with the oil seals before making a decision. Looks good – no smoke.
Classical: My benchmark is the bike before I brought it to the shop, there was not observable smoke with hot engine. Compression was good. Idle was smooth. Valves don’t wear within a few days or a few miles. I therefore just don’t believe it is a problem with the valve shafts. And even if, I would have a look at how it runs now with the seals, I would have no comparison with respect to how it runs now without the seals with the new cylinders and pistons. My benchmark is the condition before I brought it. So looking at it now with seals installed to make a decision is useless. Please remove the seals. I offer to pay for the seals since now they are used, even if I don’t want them.
Romantic: Will not charge, reputation at stake.
Classic: Reputation is not at stake, I am a hardheaded, different customer with a very different mindset and attitude, other customers are happy with the shop’s work.
(At this stage I remembered the classic and romantic concepts of Pirsig and decided to get back to the book).
From then on I stayed silent. There was just no point to continue the discussion. I got the feeling that by not wanting the seals I am questioning his authority, given the Asian context, he might loose face in front of his staff and/or his customers because a customer rejects his modification that he has so successfully introduced. No point in continuing this discussion.
Given the very different views there is just no way that this will work for me. I base any decision on technical assessment, understanding of the underlying technical principles, measurements and evidence, logic, conclusions and then decide.
I pick up the bike two days later. Trying to be as friendly and understanding as possible and also comforting with respect that I don’t want to challenge his expertise or damage his reputation. For me, I just want to get the bike, get out and get it over with, and never bring one of my bikes, or boats, to a shop again.
At the shop, after starting the bike, there is a bit of smoke, but hardly visible. Nothing that would have alarmed me with a cold engine. The ride back home is uneventful, but the bike shakes, sometimes violently, at idle and dies twice. Obviously the carbs need synchronization. I pull out the sync clocks and connect them. Left cylinder shows -0.2 bar, right cylinder -0.1 bar. Accelerator cables are all on the bottom with lots of play. I try to adjust idle with the idle screws and get an even reading, it only gets worse. There is something very wrong here. On the good side, no more smoke visible, so obviously not a problem with hot engine.
I pull out the compression tester. Left cylinder has 8.4 bar, right cylinder has 6.8 bar, compression ratio according to the specification is 1:9. There is the explanation for the inability to adjust the idle. Something is very wrong. Deep frustration settles in.
Classical: Low compression is usually cause by worn pistons and rings. Sometimes by leaking valves, but this is the valve seat, not the valve shaft, and since the shop has polished the valve seats as part of their “additional service” this is very unlikely to be the cause. Even if the shafts are worn by a few fractions of a mm, given the length of the valve seat the tilt would be minimal it is very unlikely that the valves leak, so with high probability it is the pistons, cylinder or rings. Bored to the second oversize already, maybe wrongly, so maybe the cylinders are gone, if bored too big. Problem is since I don’t know what else the shop did, they made all this additional work that one did not ask for, I don’t trust the bike anymore. Maybe the cause of the problem is something else they did? How would I know without doing it myself? He asked me to drive in the bike slowly, 60 km/h, maximum 80km/h. Back home we used to say 3/4 of max revs. 80km/h would be 50% of max revs. Looks like he does not trust the work himself?
Romantic: Good reputation, customers are happy, we provide extra service, honor German engineers.
End of story, never again.
Other issues that came up as a result of all this tinkering.
I have provided the shop together with the cylinders and pistons one set of cylinder foot gaskets, cylinder head gaskets and the rubber seals for the pushrod tubes. Gadgets are not supposed to be re-used. I never re-use them, always use new ones, I had several cylinder foot gaskets leaking before. I also use very little, if any, silicone gasket sealant. None on the head gasket. As long as the surfaces are smooth and clean, no silicone gasket is needed. The shop has now disassembled – assembled the cylinders at least three times.
- For the initial conversion (found oil)
- For fitting the oil seals
- For removing the oil seals
I am 100% sure they did not use new gaskets each time. I also noticed that they have used some excessive liquid sealant with the head gasket. Not my thing. I wonder what the surfaces look like. Will find out when I convert the bike myself.
Next steps for me:
1.a) Convert the bike back to the Siebenrock kit, the bike performed good with it and in the meantime I got some assurance that engine cracking would not occur at the way I am using the bike in the Philippines.
1.b) Alternatively, buy some second hand cylinders, original size, bore to 1st oversize and use the other piston kit that I still have.
2.) Sell the current oversize piston / cylinder set, since it was done by the top shop in the Philippines there should be a market for it.
3.) Avoid motorcycle repair / customization shops by all means.
Afterplay
The next day I opened the engine housing of the Honda Dax, the other bike that I had at the shop. I wanted to check what sort of alternator it has because the primary ignition coil seems to be broken and the 6V light is very dim so I am thinking of replacing it. The same shop offers a conversion kit for 12V and suggested to use this. However, the bike came with two different crankshafts and one needs to know which one is used in order to order the right parts. So I decided to do it to check.
After opening the alternator cover, I found that the flywheel, which was a bit rusty but fully functional when I had restored the bike earlier this year, was now freshly painted and paint had settled in the thread that is used with the flywheel pulling tool to remove the flywheel could not be attached anymore. In addition some of the screws, which I had bought new in February, are now damaged by either using the wrong screw drivers or by not using an impact screw driver for loosening the.
Classical: The flywheel was perfectly OK, and functional. A bit of rust but that is normal at this age, the bike is likely from the 1970s, it does not affect the function and nobody sees it when the engine is closed. Now it is painted, rust cannot be seen, but I had to use a wire brush to clean the thread and a grinder to smoothen the first rounds of the thread to be able to use the flywheel removal tool. This modification was not needed, useless and counterproductive.
Romantic: (Extra service to the customer?), looks better.
Next steps with this bike:
I ordered the alternator plus ignition from a trusted shop in Germany, shipment to an address in Germany, my daughters will bring it next time they visit.
Will do the conversion myself.