Maintenance Musings, Revivals and More

It would also have been interesting to show that the Norton had a much better combustion chamber shape and downdraft intake ports. Ignition timing at full advance was almost 10 degrees less than the Triumph twins. The engine also had axial crankshaft oil feed and a gear oil pump along with internal pushrods that were solid advantages and a good reason for keeping the engine basically unchanged for the new Commando.

Really enjoyed the article.

– Gary Arnold, Michigan

In addition to not working on quality with the mid-1960s arrival of the “Japanese Standard” for oil leaks, electrics, etc., I do remember the moans I heard from Triumph and BSA riders when the oil-in-frame bikes hit. “What are they thinking,” and one more nail was driven into the BSA, and soon to follow, Triumph coffins. I appreciate your discourse on results of less ignition advance as used by Norton. This may get some readers scratching their heads. – Ed.

CBX mysteries and maintenance musings

Some background information and rumors related to my 1979 Honda CBX 1000, engine number CB1E2002313. I am the second owner of this bike. I was told that Honda left out a main bearing and the result was a broken crank. Upon reassembly, they thought they followed the Honda service manual which resulted in the “25-mile valve job”. That is to say, they misaligned the 4-cams and the timing chain broke. The result of that was a bunch of new valves and probably more. I bought this bike with 4000 miles on the clock, and it has run well. But it has always burned a quart of oil every 500 miles. It isn’t leaking out and the back of the pipes are carboned up and the plugs gunk up too. Never more nor less, and it makes no worrying noises. The cams show no signs of wear. I’ve put more than 10,000 more miles on it, and it still runs well. Would the CV carbs cause the compression readings to be low (110-125)? Or maybe the cylinders are just carboned up too. Could they have reused the valve seals (or maybe just really old), and they are leaking? And if so, can I stuff greased rope into the cylinders doing one at a time, move the piston to TDC, remove the cams, and change the valve seals? I do not want to remove the head for fear of what I’ll find. If it ain’t broke don’t fix it! Since it has always been good, I don’t want to do anything to change that.

– Thomas Georgi, Bristol, VT

Your CBX certainly has a “storied past.” Though somewhat complicated to perform, a leak down test will explain a lot. My hunch is that the valves hit the top of the piston(s), smashed the top ring land, and may have broken a valve guide. Camshaft to crankshaft timing is critical, regardless of the machine you are working on. Assemble the engine, spark plugs out, rotate the crankshaft by hand, and recheck all your cam to crankshaft timing marks. Only then do you add fuel and spark. – Ed.

Building the perfect BMW ride

I just read your write-up on the R75/5, great piece. This is my ’71, with R90/6 cylinders, heads, later carburetors, and 5-speed with kickstarter for looks. BMW discouraged bolting on the 900cc top ends, but my friends all did it with no long-term problems.

– Andrew Granovsky, Port Hueneme, CA

Chasing speed and unforgettable rides

Wow! I just finished reading the Sept./Oct. issue with your excellent article on BMW Airheads and a reader report on Yamaha street bikes that struck a chord.

The ’70s were exciting times for advances in motorcycle design and technology, as mirrored by my own experiences. Recently divorced and looking for my first bike, like many newbies to the sport, I started small with a used 1972 Yamaha RD-250 (2-stroke) and managed not to scare myself too much, so I moved up to a used 1971 XS-650 (4-stroke) that was much more enjoyable and able to carry a passenger.

The local Yamaha dealer then talked me into a recently traded TX-750 (big mistake, an overweight pig that couldn’t corner), so I decided to do more research and consider several brands after test drives on friends’ bikes.

After looking at a Honda CB-750, Ducati 750GT, Triumph Trident, Yamaha XS-750, and a Norton Commando, I took a chance on a 1975 Moto Guzzi 850T (liked the shaft drive and handling, but hard to get used to the torque steer). I sold it to a friend when I finally found a sport/touring bike with significant advances and WOW factor — the BMW R90S.

This had everything I desired: low-end torque and weight distribution, low mounted bars, 70 HP, twin discs, mini-fairing, 6.3-gallon tank, under 500 lbs., and a real 125 MPH speed! This beauty took me on many trips in the Eastern USA, from Maine down to the Carolinas, and I imagined I was Reg Pridmore when traveling the Blue Ridge Parkway.

After replacing a noisy drive shaft, I sold it to another friend and moved up to another Hans Muth design: a 1982 BMW R100RS, which was even better for touring with more fairing protection and factory Krauser bags. After years of enjoyment, I finally had to sell it due to time/work/business concerns and, of course, now regret the decision.

Yes, these BMW Airheads were expensive in their day to buy and repair (even more so now, as they are priced as “collectibles”), but at 75 years old, I will always have the joyous memories of riding the very best of that era.

– Jim Tisdale, Glastonbury, CT

Thanks for your letter, Jim. Its arrival at our office coincides with the story on Ken Morris’ R90S in this issue. Might help you recollect your experiences back when you owned a Daytona Orange R90S, and maybe should have kept it. – Ed.

Classic bike maintenance goes beyond a shine and a spin

I have been moved to write this letter after seeing recent articles and photos in many special interest cycle magazines. Many contributors have beautiful bikes, very clean and correct appearing.
You may get/have a well-restored or a great barn find. i.e. “just needs a battery and fresh gas.” Don’t forget, many old bikes were not just “jump on and ride” even when new. As an older cycle owner and mechanic, I have known our machines were just that, machines, and will still need special attention, i.e. preventative maintenance and knowledge of the details that are critical to our safety and the cycle’s reliability.

Some simple, yet overlooked details are the 1/2 round clamps at the front axles, handlebar clamps, master cylinder (clutch & brake) mounted on the bars. Most Japanese bikes have one side of these clamps thicker than the other. The thicker side, usually to the front on axle clamps, must be tightened first. This will leave a gap on the opposite side and makes the clamping circle a round hole, not oval. The closed side should always face forward, then torque to proper specs, forward nut or bolt first. Many older European bikes have an equal gap, front and back so again, install and torque per the manual. Clamps can crack or loosen if not done properly. Close inspection of these decades-old parts is proper.

I was reading a popular magazine and their current project bike is built with many expensive “one offs,” a $10,000 frame and many other parts built by many knowledgeable professional people. The final photo showed a very nice bike that will be very capable and looks great. The one thing I noticed was the chain master link clip was on backwards, open end facing toward the direction of the chain rotation. This is a small thing but the “what ifs” start you thinking.

When tightening an engine or other component in a frame, check how much gap is between the frame and the component. If you pull together too much of a gap, the frame is now under tension and mounts or even the frame can crack. This was the case with the Kawasaki H2 750. It was common on many older H2’s and shims had to be placed in the gap before the bolts were tightened. Shims were U-shaped and had to be mounted with the open side facing down to lessen the chance of them falling out. Many frames were damaged by this small omission.

Always check your work and try to locate any information on your specific bike from dealers if they still have older service notices or check your make’s archives on the web. A great ride can be ruined by some very small things.

– Greg Smith, Ligonier, PA

Few of us doing builds and restorations have decades of professional technical experience, and can always benefit from “safety alerts” such as yours. Over the past few years, I have learned that the online auction company Bring-a-Trailer has raised the bar for cosmetic and mechanical motorcycle restoration. While most auctions present you with five photos of the offered machine and minimal history, BaT listings may have as many as 150 photos, plus “cold start” and riding videos showing that things are in pretty good order. The comments from those watching each sale further nitpick or support what they see in photos and documentation; it’s almost a competition to find problems with the offered bike or car. To your point, while replacing the drive chain on my 1970 CB750, summer of 1970, I put the master link clip on backwards. When the state trooper stopped to check on me at the side of the road, he noted my rear tire’s illegal tread depth, wrote me a ticket (then left) which forced me to attend traffic court. Last time for that mistake. – Ed.

Gold Wing café racer revival

I’m writing in to share the story behind my beloved Gold Wing café racer. The bike started as a birthday/graduation gift from my family in April of 2024. I’ve been building old motorbikes for a few years. This particular Gold Wing was important to me, as my father has had one for as long as I can remember. It was our first attempt at a café build — or any kind of build, for that matter. My father did the majority of the legwork, and I stood by with wrenches in hand, wide-eyed, with a growing passion for the old classics.

While searching social media marketplaces, I came across my “Hotwing” and was determined to get her home. What I thought would be mostly cosmetic modifications and some light fabrication turned into a five-month build. Upon the initial teardown, I discovered the wiring was in turmoil. The previous owner had cut off the wiring for the wind jammers, followed by what I can only describe as an “enthusiastically blind” free-for-all wire removal. The OEM coils had been replaced with a coil system from a Dodge Neon, and nothing was properly cut or crimped at the connections. The disarray of finger-twisted and haphazardly electrical-taped wires was overwhelming.

Without the trusty aid of a Clymer manual, I turned to every Gold Wing forum Google could offer me. After a brief search, I found the exact twin to my bike in its entirety. I brought it home that day and immediately began investigating how everything was supposed to look. With one more forum search, I found a complete, color-coded wiring diagram for my bike. I photographed every small detail of plugs and locations, then got to work gutting and swapping everything into my bike. It took a solid month and a half to rewire and modify the taillight system, but finally, it was time to twist the key. In a flash, I had power to everything.

I swapped the stock bar switches for those of a CB750. The real challenge began when I discovered a bad head gasket and water pump. After anxiously waiting for new gaskets, I swapped heads and replaced every gasket and O-ring. The calipers had to be renewed, and the carburetors rebuilt and synced. With some patience and plenty of guidance from my father, I got everything in top shape.

The journey of building this machine taught me so much about the engineering and perfectionism of Honda. It also gave me the knowledge I needed to help my dad get his bike to the style he’s been working toward for quite some time. I encourage anyone to jump at the opportunity to dig into one of these beautiful old machines!

– Rob Hall, Gibsonville, NC

You are to be congratulated! Rewiring a motorcycle is an extreme challenge, yet you have no doubt learned so much about wiring, but also close review of a used bike before purchase. Enjoy the Gold Wing Café Racer ride you brought back to life. – Ed