NTNOA Info-Library

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Brit Bike Shopping Tips
Caveat Emptur; Let the Buyer Beware or How to Check Out a Norton
Combat Comments
Identity Crisis or Name That Seat
The Art of Motion: Motorcycle Restoration

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Brit Bike Shopping Tips

For all of those in charge of acquiring their own Christmas or birthday presents (or spending money set aside for the wife and children's presents), here’s a handy guide to help you interpret the classified ads.

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Caveat Emptur; Let the Buyer Beware or How to Check Out a Norton

Unlike brands that had years of flawed frame design and other major problems, all Commandos are basically similar, and everything can be fixed. The ‘72 Combat was the absolute worst year in terms of reliability. While the '73 models by contrast, already had most of the improvements including the box-section head steady, camshaft bearings that won't blow in the engine, an oil filter, and above all, Superblend main bearings.

In any event here are some things to look for:

Frame The loop holding up seat can bend if really heavy loads are placed on the passenger seat. Fix it by straightening and installing triangular gussets to reinforce.

Isolastics Put the bike up on center stand and try to move the back wheel back-and-forth. It should not feel loose or clunk from side-to-side. Vibration from the engine should be startlingly pronounced at idle, and diminish markedly at about 2750 rpm. Fix it by rebuilding the rubber mounts. The front is easy and if necessary do the rear. This one is much more difficult.

Engine Check the big, finned nuts that hold exhaust pipes on. If the threads in the head are stripped, its a $100 or so to repair. Engine should start and run fairly easily considering this is a British bike. The ends ofplugs should be a light tan color. Fix it by doing a tune up. If the slides in carbs rattle a great deal, carbs may be worn. Rebuild or replace as needed.

Do a compression test, preferably after engine is warm. Actual figure is less important than that the two cylinders be roughly the same. Significantly lower compression in one means a top end rebuild. Take off the points cover and examine auto-advance (if no electronic ignition has been fitted.) If the cam is has much back-and-forth play, it is wearing out, and auto advance will eventually need replacing, preferably with electronic ignition.

Engine oil This should not look extremely dirty and sludge filled, nor suspiciously clean, as if just changed. Oil in gearbox should preferably have been gear oil rather than engine oil (check for stinky, sulfurous smell) and should be reasonably clean. Condensation in gearbox is a bad sign of sitting out in the elements.

Gearbox If the owner allows, take the cover off the primary case. The owner probably will not permit since oil will run out everywhere. Or take middle inspection plug out of cover. The primary chain should have some sag in it. If not, it's been straining the gearbox. If pressing down on the rear chain with your foot causes the primary chain to tighten, the main sleeve bearing in gearbox is worn. If the kick-starter operates roughly, or especially if it moves down on its own when the bike is running, there could be serious gearbox trouble immediately ahead. Fix it by rebuilding the gearbox. ( If lever moving down on its own, rebuild gearbox before you ride it any distance.)

Alternator Stator If owner let you take the cover off primary, take a look at the alternator stator, to see if insulation on the wire coming from it is cracked. Handy people can repair / replace this at home.

Instruments The speedo and tach should work. Rebuild is about $100 and not a do-it-yourself item . Veglia instruments on later machines which were installed on 1973 and later machines are probably not worth fixing.

Tires and Exhaust Problems are obvious. Tiny cracks in sidewalls of the tires are dangerous.

Oil leaks All the rubber parts in a 20 year plus old bike are probably dried out and the bike will leak some oil. Replace them as you go, and eventually the leaks will be history; it's a bad advertisement for Brit bikes to leave puddles behind them.

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Combat Questions & Comments

Question

I've heard that the Combat Commandos should be avoided. Is this true and what makes them different?

Answer

COMBAT HEAD: Norton shaved 40 thousands off the head to increase the compression from about 9:1 to 10:1, the 850 put it back. One thing Norton didn't do, and should've, was mill the same amount off the push rods to preserve the proper valve geometry. Some Norton dealers will mill your push rods for a Combat head; without this, valve-guide life is reduced. Alternatively, you can get a metal plate to put under the cylinders that adds the 40 thousands back so save the push rod modifications and get back to 9:1 compression.

CAMSHAFT: The Combat had the high-lift SS camshaft which sacrifices a broad power band for more top end. It requires certain head modifications to prevent coil-binding (obviously, all Combat heads have these). The result is narrower, peaky power band with more ponies at 7000 RPM.

MAIN BEARINGS: Prior to the Combat, Norton’s were built with a roller bearing on the drive side, and a ball bearing on the timing side, which carried less load. The increases in power over the years were straining this bearing, leading to bottom-end life as short as 10,000 miles, so with the significant power increase of the Combat, Norton knew it had to do something to increase lower end durability. They decided to go to roller-bearings on both sides, supposedly because of their increased bearing area. Unfortunately, roller-bearings are far less tolerant of misalignment than ball-bearings. In hard use, a 2-bearing crankshaft flexes slightly, harmlessly to the crankshaft and formerly neutralized by the easygoing nature of the ball bearing. With two roller bearings, the flex led to embrittlement of the rollers, scoring of bearing tracks, and bottom ends that would often blow out within 1000 miles, seldom lasting beyond 4000.

The result, of course, was a financial and public-relations disaster, with virtually all Combat bottom-ends blowing up within the warranty period, but there was no good solution, since the ball-bearings were themselves too weak, even for the pre-Combat engines. For awhile, stopgap repairs were made using high-strength ball-bearings (i.e. with extra balls, and notches cut in the tracks to stuff them in). The twin, high-strength ball bearings were better than nothing, but not truly satisfactory, and a crankcase with two ball-bearings is intolerably hard to disassemble. Eventually, a roller bearing was specially developed with slightly barrel-shaped rollers called the Superblend. This has the bearing area of a roller-bearing coupled with the flexibility and tolerance of a ball-bearing. It has the part number NJ306E, and will go 100,000 miles. Note that the bearing that blows up in 1000-4000 miles has the part number NJ306, try not to get these confused.

In short, the bearing problems came and went in '72. The Norton Tech Digest claims the Superblend was introduced at engine number 207197, but there are engines that are after that number & did not have them. It's hard to believe than any Combat engine still runs on the original NJ306 bearings, including SURF COMBAT; some '72's may still have the heavy-duty ball-bearings.

Edited from the Internet

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Identity Crisis or Name That Seat

This information comes from an expert in upholstery specializes in custom work.

Begin by measuring the dimensions of the old faded lettering on your seat. Write it down so you don't forget. Then remove the old lettering using lacquer thinner. Wipe gently. Do not rub or you may take the black dye out of the seat. Let the thinner dry, and keep repeating until the old lettering is gone. If a little bit is left it probably doesn't matter because the new lettering should cover it adequately. This also has the advantage of thoroughly cleaning the part of the seat on which you wish to apply the new lettering. (If you do take some of the black dye out of the seat, he said any upholstery specialist should be able to re-dye it for you to match the rest of the seat, or even re-dye the whole seat to like-new shiny blackness. It gets trickier matching the colors if your seat isn't black.)

Then you need to make a template of the logo you are going to use. Get a copy of the logo larger than that which you ultimately want. Photocopy it on a copier machine with a reduction feature. Play around with the reduction until you get it down to the exact size you want. At this point you feed in the stiffest piece of paper the copier will handle, because stiff paper will be easier to work with in the next stages. Carefully cut out the paper around the lettering until just the logo is left.

You now need piece of vinyl about three-quarters of an inch larger in width and height than your logo. Using the paper template of the logo and a very sharp upholstery knife, cut the lettering out of the vinyl so that at the end of the process, you will have Triumph, Norton, or whatever cut out of the middle of the vinyl piece. This may be easier to do if you first glue the paper template onto the vinyl swath with a water soluble glue, because that will keep the paper template from moving around while cutting. Be sure it is a water soluble glue, and then you can peel off the template and easily remove any stuck on paper or glue from the vinyl template using a wet cloth.

Now stick your newly created vinyl template onto the seat itself exactly where you want the lettering to be, again using water soluble glue. Apparently there is special water soluble vinyl glue which works best, but any water soluble glue will do. Once the glue has dried, you use a special type of vinyl spray paint, available at most well-stocked hardware stores. This vinyl spray paint will soak right into the vinyl without

bleeding, and thus won't fade easily in future. Cover the exposed parts of the seat with newspaper and masking tape it on. Then spray the template with the vinyl spray paint following the instructions on

the can. Once the spray has thoroughly dried, pull off the template. Some glue will remain on the seat, but you can remove it with a wet cloth. Be sure the vinyl paint has dried completely before trying to remove the glue though, or you might take off some of your new paint.

Spraying the seat every month or so with Tana All Weather Leather Protectant supposedly if you do that as standard maintenance, your seat and lettering should never fade again, or at least not for several decades.

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The Art of Motion: Motorcycle Restoration

Motorcycle restoration is in many ways the perfect hobby. It combines an interest in things mechanical, the joy of craftsmanship, the satisfaction of collecting, the beauty of art, the excitement of riding and the value of investment. Deciding where to start is the hard part.

The traditional approach has been to concentrate on English bikes of the 1950's and 60's, especially the sporting or racing 500cc singles, like the Manx Norton, BSA DBD34GS Gold Star or Velocette Thruxton. Also at the very top of the heap in terms of desirability are the Vincents the 500cc Comet, the 1,000cc

Rapide and the 125mph Black Shadow. In recent years, the prices of all these classics have been rising so rapidly, they are now out of sight for all but the most well heeled motorcycle investor.

Not to worry, the second rank of English bikes, mostly 650cc twins, is both more numerous and more economical. The best of these are the twin carb Triumph T120 Bonnevilles from 1966 to 1970, any 650 Norton from 1960-1970 and the standard BSA 650, the A10. More available, and gaining in popularity, the later Bonnevilles, Norton Commandos and BSA Lightnings.

After this, the list of desirable classic motorcycles gets a lot more confusing, if no less interesting. That's because, as prices have risen, greater attention has been paid to motorcycles that, while reliable, innovative or a pleasure to run, never created the same cult following.

A bit More Exotic

This list is a lot longer than the ones above, but it would certainly have to include the delightful Norton ES2 single, the enclosed bathtub model Triumph Speed Twin or T110, Ariel's fully-enclosed 250 Leader, the Matchless G80CS desert racer, Benelli 750 six, BMW R69S, Ducati Desmo singles and twins; and even early Vespa scooters. On this side of the water, a thriving restoration movement exists for pre and post war Harley Davidson’s and Indians. Large clubs are active, much help can be found from enthusiasts and parts are surprisingly plentiful.

Before you decide what make and model you'd like to work on, take some time to review the field. The best way to do this is to attend meetings of your local vintage bike club, such as the North Texas Norton Owners Association.

Go to Daytona

For an instant immersion course, go to Daytona for Bike Week and take in the classic racing on Monday. There you'll be able to walk through the infield pit area and see hundreds of classic and vintage bikes, many being prepared for racing just as they were thirty years ago. Daytona also attracts dealers and individual sellers who show off their bikes at an official auction, various flea markets and outside numerous watering holes. On a more local level there are area Vintage British Bike Rallys occurring throughout the year.

The next thing to do is to get subscriptions to Classic Bike magazine from Britain and Walneck's Cycle-Trader magazine from the United States. Classic Bike contains excellent articles on individual machines, beautiful full-color pictures and an extensive classified section for parts and fully restored classic motorcycles. The prices that go with these ads will give a good indication of how popular and how available various models are. That's also the reason for buying Cycle Trader, because Walneck's can give you an indication of what the same models are selling for in the United States.

Finally, once you've decided what manufacturer and model you're interested in, you should join the club that has members with similar interests. There is a club for most popular marques, including Vincent, BSA, Triumph, Ariel and BMW. There are even clubs for specific models, such as the Gold Star Owners Club.

Once in the club, you'll be able to see what bikes are currently for sale, and get the names of club members who know what bikes might be for sale. This is, by far, the best way to buy a specific model. Club members are usually pretty straight with when it comes to the value and true state of their machines. A second approach is to find a motorcycle repair shop that deals with a specific model. These often have basket cases ready for restoration. They can usually be talked into doing the mechanical work, while you tackle the cycle parts and cosmetics.

The Basics

The three essential ingredients in any bike restoration project are an engine, a frame and a manufacturer's parts book. The engine and frame are the heart of the project; the parts book, with its exploded diagrams, is the brains. Let's assume you have these three things. The first step is to either tackle the motor rebuild yourself or haul it to an engine shop that specializes in completely rebuilding your type of motor.

It should be obvious why you need to have a 30-year old motor rebuilt, but there is a not so obvious reason as well; getting it clean. The head, barrel and case have to be bead blasted and all the bright metal parts have to be mechanically polished, and this is the time to get it done.

While that's underway, you can get started on the frame and swingarm. This should be sandblasted and then examined for cracks, twists, missing tabs, extra holes, and battery acid damage. If any welding is needed, get it done now. A good tip at this point is to dry assemble the bare frame with the newly rebuilt engine.

Assuming it fits, send it out for powder coating or painting with industrial polyurethane. Stove enameling was the method used by most manufacturers, but it's very hard to find a source for this process today.

At this point you'll be starting to think about what kinds of nuts and bolts you're going to use. As with all aspects of motorcycle restoration, there are more than two schools of thought about this too. Traditionally, most engine and frame bolts were cadmium plated steel. One hundred point restoration judging will require the same kind. Unfortunately, cadmium plated bolts will eventually rust if put away damp, so many people prefer using stainless steel. Most of today's stainless nuts and bolts are in American sizes and threads, while all the original bolts were in British or metric sizes. You'll have to decide for yourself.

The next two things to worry about are the shocks and forks. The shocks are easy because you can buy brand new replacement shocks for most classic bike styles.

Forks

Assuming you have an intact set of correct forks, you should check them for straightness and excessive wear. If either needs fixing, send the forks to a fork specialist.

Rear hubs for most English bikes are easy to find as are front brakes. Steel wheel rims are readily available as new or rechromed. For some bikes an attractive alternative is to use a set of alloy rims, such as those made by Akront and a matching set of stainless steel spokes and nipples. Table top wheel lacing is a realistic possibility for most people, although final balancing and run out correction is best left to an expert.

What rubber?

Conflict between traditionalists and pragmatists can be expected over the right kind of tires you should fit on your rims. Many traditional tire types are now available, so these should be considered. If you plan to enjoy riding the bike, buy the closest available size in a modern tire, preferably from the same country as the bike. The same argument will take place over hand grips. Your choice is to opt for the original look in hard rubber or to install foam grips and ignore the critics.

By this point, the importance of a working center stand will be apparent. With the forks, swing arm, and wheels installed, your bike can now stand on its own if you have one.

The next steps are finding, sandblasting and repainting the fenders, tank and other bodywork, such as side panels. Unless you are in the auto body business, get this professionally done. Poor paint work on motorcycle body parts, especially the tank, can ruin an otherwise outstanding restoration project. For many machines replacement body parts can be obtained in the US or from England, as well as tanks, exhaust pipes, mufflers, headlights, seats, decals and wiring harnesses.

When original, or original pattern after market parts can't be found, there still is a chance you can get a fiberglass or alloy version. Your fellow club members will usually have a line on where these, and other hard to find pieces, can be obtained. One nice thing about motorcycle restoration is that if you've had to cut corners to get your bike on the road, you can always go back at it and replace second rate parts with genuine originals once you have the money or find the parts. Obscure sources of Original Equipment Manufacture (OEM) parts are continually popping up.

So if the sound of a classic bike engine rattling your garage windows is music to your ears, take the plunge. Remember, unlike almost every other hobby involving restoration and collection, when you're finished you get to ride it! That's when the fun really begins, scattering leaves on a two lane ribbon of winding asphalt, your exhaust note rising like a symphony as you tuck into your tank and pick the perfect apex on the next corner. If you've done your restoration right, you'll be transported back to the 50's, 60's or 70's when both the bike, and you, were young.

Not a bad feeling. And at the end of the day, as you pause to turn off the light in your garage and go to sleep knowing that the darn thing is appreciating.

Edited from the Internet from an article by Frank Hilliard 1994

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Copyright © 2000 NTNOA All rights reserved.
Revised: January 31, 2011 .