The Service Department

THE SERVICE DEPARTMENT

JOHN DUNN

VICTORIA WHO?

Recently I visited a friend in western Mass. who had on his property a motorcycle which he was attempting to put into running condition.

The machine was one which no one in that area or this seems to have heard of, hut for some reason I cannot explain, I feel I have heard of it before, and I think they went out of production around 1956. The name of the hike is Victoria. The name is enclosed in a circle on either side of the gas tank, in block letters, with metal script over it saying Berglmeister.

Could you tell me who made the Victoria Berglmeister? It is a V-twin, on the order of the new Moto Cuzzi V-7 two cylinder bike, but I can't decide whether this Victoria is a 350, 500 or 700cc machine, and have not the mechanical knowledge as to how to measure cc capacity.

I have been riding motorcycles since I was 13, but always left the engine work

to my father. Now, at nearly 23, I find I had better buy an old hunk of junk and rebuild it on my own, so as to be familiar with said work.

David N. Jacobs New York, N. Y. The Victoria was of German manufacture and went out of production in the mid-1950s. CW has no knowledge of this marque. If any reader has any information related to this make of machine. CYCLE WORLD would be pleased to pass it on.

To find out the capacity of the engine it is necessary to know the swept volume of one cylinder; then multiply this volume by the number of cylinders. If you know the bore and stroke and number of cylinders, the capacity can be easily worked out by employing the following formula:

IT r x S x N Where, vr — 3.14

r = Half the diameter of the cylinder bore multiplied by itself. S = Stroke

N = Number of cylinders Either millimeters or inches can be used for bore and the stroke, but like units must be used. Do not compute with bore in millimeters and stroke in inches.

Here is an example for a twin cylinder engine having a 50mm bore and a 50mm stroke:

3.14 x 25" x 50 x 2 (two cylinders) = 3.14 x 625 x 50 x 2 = 1962.50 x 50 x 2 = 98125 x 2

= 196250.0 cm (cubic millimeters) = 196.25 cc (cubic centimeters)

If the bore and stroke are given in inches, the answer is in cubic inches. To

convert from cubic inches to cubic centimeters, divide the answer by 0.061.

With the cylinder head removed, the stroke (total piston travel) can be measured. Measure the full travel of the piston, as in Figure 1 :

The bore diameter can be measured with a vernier caliper or an internal micrometer.

An alternative method for measurement of piston displacement is to fill the cylinder with a fluid from a calibrated glass. This can be carried out with the cylinder head on and the spark plug removed. It is best to tilt the engine so the spark plug hole is in a vertical plane. Turn the crank until the piston is at bde (bottom dead center), and pour the liquid from the calibrated glass through the plug hole until the cylinder is full to the bottom threads of the plug hole. This will give the total volume of the cylinder (swept volume plus the combustion chamber volume). Empty the fluid from the cylinder. Make sure none remains. Refill the calibrated glass and bring the piston to tdc (top dead center). Fill the combustion chamber with the fluid, and note the quantity used. To find the swept volume, subtract the combustion volume from the total cylinder volume. If you desire the compression ratio as well, divide the combustion volume into the total cylinder volume.

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The main problem with this method of measurement is that if piston rings and bore are worn, fluid escapes past the rings into the crankcase, to give a false reading. It also is possible to get trap air in the cylinder if odd shaped pockets exist. When the cylinder is nearly full, it is good practice to rotate the crank slightly back and forth to dislodge pockets of air.

SMOKE AND NO FIRE

I am very much baffled about the engine in my new 1964 Yamaha 250. It starts easily, but will not fire on the right side. The left side pumps clouds of smoke out the pipe.

I am really not concerned with the right side not firing, because 1 just haven't had the time to correct it. It's the left side I'm baffled about. I suspect there is a bad seal somewhere, but I have no idea where. Is it possible that oil from the gearbox somehow is finding its way into the crankcase? (I have been mixing gas and oil at a 20:1 ratio, using a recommended cycle oil.)

Since I can't afford to take the engine to a shop and have this corrected, and since I consider myself a pretty good mechanic, I would like to try and correct it myself.

Alan Quackenbush

Covina, Calif.

The center main bearings on Yamaha twins are not lubricated by an oil feed from the gearbox, which is the case on some 2-stroke twins. (This eliminates the probability of a leak from the gearbox due to a faulty center main seal.) There is a possibility that the joining faces of the crankcase are not sealed properly, which allows a leak path from the gearbox to the left crankcase. It also is possible that the drive side crankshaft seal is defective, which permits oil to be sucked from the primary drive case.

It will most likely be necessary to completely dismantle the engine to effect a permanent cure. This really is a job for an experienced Yamaha mechanic, as the cranks must be assembled and disassembled with a press. However, if you feel competent, you should acquire a Yamaha work shop manual and all necessary workshop special tools. You will need a clean place to work with sufficient room to lay out all parts in order of disassembly. Clean all parts thoroughly. Replace all seals and gaskets. Inspect the crankcäse mating faces for possible imperfections. Assemble by the procedure outlined in the workshop manual. Lubricate all bearing surfaces, including cylinder bores, with a film of engine oil.

While the engine is dismantled, check all components for wear and replace if necessary. If you make any of the gaskets yourself, be sure the cylinder base gaskets have openings for transfer passages. Quite a few people overlook this, and thus block the transfer ports.

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WOBBLE AND CRASH

/ am a newcomer to the sport of motorcycling, and have been reading CYCLE WORLD for a year and one-half, or 10,000 miles. I have a serious question.

My motorcycle is a 1966 CA 77 Honda Dream (305cc), equipped with windshield and bags. I was cruising at 60 mph on a straight and level road, when the handlebars, or front end, started to shimmy badly. Consequently I was thrown off, and my leg was broken. My pride was also hurt, and I feel this shouldn't have happened.

This is a serious thing, and 1 can't find out why it happened. The dealer says it was a high speed shimmy; some say it was the fault of the spring forks in the front end. Regardless of hearsay from onlookers, I wrote to you. 1 would appreciate learning the reason it happened and what to do in case it happens again.

Harvey Ledwidge Encinitis, Calif.

When in good condition and proper adjustment, a Honda CA 77 should negotiate a fairly bumpy stretch of road at full speed without steering wobble and a crash. Worn or slack steering head or wheel bearings could cause a steering wobble. A defective suspension unit or swinging fork pivot also could cause this problem. Incorrect (too soft) tire pressures or a buckled wheel rim may have been the cause.

How much weight were you carrying in the rear pannier bags? How rigidly are the pannier bags fitted to the frame? It is most important that the pannier bags are very securely attached to the machine, particularly because loaded vibrations started by their swinging will travel through the frame to cause front end navigation to be very uncertain. Excessive weight behind the rear wheel spindle also can cause a steering wobble. If you are traveling with a lot of luggage, keep as much weight as possible between front and rear wheel spindles.

A large windshield also can result in some alarming steering effects when suddenly caught by a strong crosswind, particularly if the screen is attached to the handlebars or front forks.

What should one do if a steering wobble occurs? The age old remedy is to accelerate hard. Unfortunately, the malfunction usually occurs at maximum or near maximum speed, so acceleration naturally is out of the question. A rider who manages to escape a bad steering wobble usually does so with a combination of luck, natural riding ability and giving the machine head to a certain extent. A motocross rider is on the verge of a speed or steering wobble 50% of the time he rides, but does not frequently come unstuck (as you did) when things become hectic. The main thing to remember is to have your machine in a safe condition at all times. A modern motorcycle should not get out of control on the street when properly adjusted and correctly loaded.

CUTTING CONVERSION

I own a 1964 Honda Scrambler, wit/i 250cc, Type 1 Engine. I plan to make some modifications to the engine, but I am not sure what to do.

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I am stationed on Okinawa. This means I can get parts at approximately half price as compared to the cost in the U. S. I have $150 that I can spend on these modifications. I will tell you my ideas, then you can give me your suggestions on my ideas.

I want a dependable bike that will give only minimum trouble. I feel that a 350cc kit would be my best bet, yet the ones I have seen here have given owners a great deal of trouble. I wonder if this is typical of all 350 kits, or is it just the Japanese type kit that is sold here? I was told that the only weak part of this type kit is rings, and if I buy a set from the states I will not have that problem.

Is there any difference between heads of 250cc and 305cc engines? Is the cylinder assembly the same on the 250 as on the 305? Also, is there any overheating problem with the 350cc kit? The only type cam available, other than a stock cam, is a cam known as the YB. Do you have any knowledge of this cam? What type cam would you recommend for good all-around use? Also, would a full race cam be too radical? Could a wrong cam cause overheating problems? Is there any particular way of parting the intake to adapt 26mm carbs? Can any harm be done by milling the heads? How much should be milled?

By now, you should have a general idea of what I am after. What suggestions can

you give me for mild modifications? Just a few other questions about a 350 kit. Can I gain anything other than stock spark plugs on the 350 kit? What would be the valve settings? Would an exhaust such as the megaphones make any big difference? What size sprocket would I want for highway use in the States?

I would appreciate any suggestion or material covering this kit and the questions which I have asked you.

•W. D. Moran

APO San Francisco

Unfortunately, the Honda 305cc engine is more ideally suited for the 350cc conversion than the 250cc unit. It is necessary to machine the 250 cylinder barrel to accept the 350 sleeve. There is less material thickness in the 250 cylinder wall — which usually results in the machine tool cutting right through to the base of the cylinder fins. This does not occur with the 305 barrel. Also, on the 250 engine it is necessary to machine the mouth of the crankcase to accept the spigot of the larger diameter 350 sleeve. When carrying out this machining operation, it is necessary to cut into one of the cylinder hold-down stud bosses. This severely weakens the boss, which results in the threads in the boss stripping when the stud is tightened. To carry out the machining operation, it obviously will be necessary to completely dismantle the complete engine.

Smaller diameter of the 250 combustion chamber recess makes it necessary to machine the head or piston crown, or both, to

assure adequate piston to head clearance. This usually is achieved by machining the piston crown only, which often results in top ring land failure due to inadequate material thickness at this point. I would suggest that you investigate the possibility of machining the head face around the combustion chamber. It may be a better arrangement to take material from both the head and the piston crown.

Check the compression ratio and aim for 9.5:1 for street use, or 10.5:1 if the machine is to be used for racing. There is very little advantage to be gained by exceeding 10.5:1 if the engine is to be run on gasoline. A ratio of 13.5:1 would be a good starting point if an alcohol fuel is to be used.

The YB camshaft supplied by Honda is intended primarily for racing. If the machine is only to be used on the street, the standard camshaft is advisable.

The intake ports on the 250 head can be blended in to accept the 305cc engines' 26mm carburetors. Blend in gradually; do not create sudden changes in crosssectional area.

If you mill the cylinder heads, this will bring the camshaft drive sprockets closer together, and result in retarded camshaft timing. There is no provision for adjustment of valve timing on this engine, unless a special camshaft sprocket is employed. The standard exhaust system will perform very efficiently with the 350cc conversion.