The Service Department
THE SERVICE DEPARTMENT
GARY BRAY
DISTRIBUTOR MOVEMENT
My 1962 250cc C-15 BS A started misfiring severely when 1 was in the hills recently. It became so bad that I couldn't accelerate or go over 10 mph. It finally quit altogether after about one mile.
The timing has been giving me trouble as 1 have had to keep advancing the distributor after having it at one setting for a while, in order for it to start. 1 don't know if this could eventually make it miss so badly it finally quit.
My plug is new and clean and 1 have a new condenser. The points look good and no amount of advance or retard seems to help. Most of the terminals have been checked. The machine has gone about 231 miles since a new piston, rings and valve guides were installed. John R. Bucher Salt Lake City, Utah
The early BS A C-15 did suffer from circuit breaker movement. The factory distributor positioning clamp was not sufficient to hold it, which meant the distributor had to be constantly repositioned to maintain the correct ignition timing.
Standard procedure to cure this problem has been the installation of a small Allen set screw (1/4-20) at the base of the distributor mounting hole. This work is done from the outside and no engine dismantling is called for. If after re-timing the machine (1/32 BTDC at full retard) and it still won't start, the trouble may be due to either a faulty ignition coil or some difficulty in the stator assembly itself.
Since test equipment is required to determine the condition of the stator assembly, it will be necessary to see your local BSA dealer.
A BIT MORE NOISE
1 have a 1962 Zundapp 250cc, and although the functioning of its two-cycle engine is quite satisfactory, 1 would like to know if a different muffler is available. 1 believe that a different muffler — one which is not so quiet — would make it easier to gauge engine speed in shifting, yet remain within limits of Dept. of Motor Vehicles' requirements for noise. George Duffield San Diego, Calif.
While a variety of mufflers are available or can be adapted to this machine, performance and dependability may suffer when other than the muffler engineered for the machine is used. This rule applies in general to most two-cycle motorcycles.
Replacing the muffler with a non-factory unit can create trouble at the local law enforcement level, particularly if the re placement muffler is louder. Whether you would ever get stopped for a muffler violation depends on who, where, when, what kind of a mood the officer is in, and how sharp he is. In other words, there is the risk of a citation if the stock muffler has been replaced by something else. One replacement muffler for your Zun dapp that works quite well is available from the Beck Distributing Company, and it is louder. Good luck.
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MORE TOURING PERFORMANCE
I own a 650cc BSA 1957 Golden Flash. I do a lot of touring and am wondering if you can give me some advice on im proving its performance and top speed. It has a stock engine (6.5:1 compression and single carburetor). Many friends have recommended that I raise the compression to 9:1, put in a racing cam and add a second carburetor. Also, I find the dual seat supplied with my bike uncomfortable on long journeys. Could you suggest a saddle (for a single person) which could be fitted to my ma chine without too great a modification job. Peter Padley Beaconsfield, Que., Canada
Performance of your Golden Flash can be increased quite a bit without a tremen dous amount of work or expense. Higher compression pistons will help but I rec ommend going no higher than 9½ to 1 for a touring machine. The standard camshaft used in the BSA Road Rocket (#357) will also be a great improvement over the camshaft presently used in your machine. The stock Road Rocket intake and exhaust valves are larger than your present ones and can be installed with a minimum of work. A larger carburetor (1-3/16") should prove most satisfactory. Matching of the carburetor and intake port is necessary in this instance but is less work by far com pared with the problems involved in adapt ing a second carburetor to your present cylinder head. S & W racing valve springs should also be used in conjunction with the more efficient camshaft. Many different types of seats, both dual and solo, are available. The dealer in your area should have an accessory catalog to help you make your selection. In the event you desire more information in this area, you can acquire an accessory catalog at a small charge by writing any one of the accessory distributors who advertise in CYCLE WORLD. I was wondering if there is any inexpen sive way to convert a two-stroke engine into a four-stroke engine. Is it possible to use wet sump lubrication? Jim Deichier Carnec'ie. Pennsylvania
certainly would be anything but inex pensive if it were even remotely possible to change a two-cycle engine into a four-cycle. Wet sump lubrication is also out of the question. Any large quantity of oil carried in the crankcase of a two-stroke would be pulled into the combustion chamber. This would result in an oil-fouled spark plug.
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There are, however, some two-cycle motorcycles that utilize a type of dry sump oiling. Oil is carried in a tank separate from the fuel tank. By metering the correct amount of oil directly to the engine, mixing of gas and oil in the same tank is done away with.
FROM ACROSS THE POND
1 note in the Service Department column of your September 1965 issue of CYCLE WORLD a fellow by the name of R. S. Powell is having head gasket problems with his 1949 Ariel Square Four.
One of my motorcycles is a 1938 Ariel Square Four with "iron" engine and 1 have experienced the same difficulty. However, by using a gasket compouund available over here 1 have cured this problem. 1 understand this compound is not available in the States and wondered if you could supply me with Mr. Powell's full address or forward this information on to him as 1 would like to help him out of his difficulty. Jim Lee Public Relations Officer Ariel Owners Motor Cycle Club 245 Birmingham Rd. Ansley, Nr. Nuneaton Warwickshire, England
In dealing with Mr. Powell's head gasket problem it must be remembered that his Square Four is the early alloy cylinder and cylinder head model. Head and cylinder distortion is far greater on these machines than the cast iron Four. It is doubtful that any gasket sealer would cure head gasket failure on the early alloy Square Four. It would seem that a gasket cement capable of such strength could create some litle difficulty if it ever became necessary to remove the cylinder head at a later date.
OILS PLUGS
ƒ have a very perplexing problem I hope you can help me with. I own a 1964 Ducati 250 Scrambler which I ride in sportsman scrambles. At the beginning of this season 1 tried to put new rings in it. 1 got them from the dealer from whom I bought the bike and they were a standard replacement aprt. The first time the machine was started it pumped raw oil out the exhaust pipe. I tried to break them in with Gordon Jennings' "on and off" method but 1 couldn't keep plugs in it. They fouled out as fast as I put them in and after six plugs it wouldn't start at all.
When it was kicked over with the head off, it would scrape clean going down, but on the way up it would bring a load of pure oil. When the old rings were put back in it ran fine.
I asked about this at the shop and they wanted to see the barrel and piston. They miked it with the following readings: cylinder taper, .003; cylinder out of round, 0.0018; piston taper, .002. They told me that this was my problem and offered to bore it out and sell me an oversized piston for a slight fee. I asked around at other shops about it and they said this would not cause oiling as bad as I was getting it. Tom Keeble Palo Alto, Calif.
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While several causes can be attributed to extreme oil consumption after a top overhaul has been carried out, the villians in this instance are very likely the new piston rings themselves.
Lack of tension in the rings or some defect in manufacture is preventing proper oil control. I would suggest trying a different brand of rings, such as Hepolite, if you are unable to find new rings which have at least the tension of the originals.
AS WELL IN THIRD
In your August column you answered a query on the speed problem of a Honda 150. You also commented that the same type of problem existed on some 300 Dreams. My '64 300 Dream is, I believe, in perfect tune according to the book. Countershaft sprocket is 16T and rear wheel sprocket 29T; this is the way it came from the factory.
My Dream will do nearly as well in third as in fourth gear, maybe better if I let it wind full out. It lacks top speed and climbing ability in fourth gear. Seems too tall, sort of a poor overdrive. Can you suggest any changes to improve performance? F. H. Cain Seattle, Wash.
The Honda 300 Dream is geared a bit high. By replacing your present 16-tooth countershaft sprocket with a 15-tooth one, an increase of 5 to 7 mph in top gear can be realized.
TRIUMPH TROUBLES
1 have a 650cc Triumph TR6 S/C, '65 model. In 4800 miles my dealer and I have been unable to time the thing properly. In following the factory prescribed routine, we find that we come out too far advanced. Setting by ear gives an engine that will run but performance in the 1/4 is poor. (16.57 secs. @ 78.82 mph.) From there to carburetion. Stock specs say a 310 main jet and #7 needle position. Trial and error gave 380 main jet, #5 needle position. That gave us a speed of 87.71 @ 16.56 sees.
Still poor performance at best. All trials were with open exhausts, Amoco hi-test gas, Champion N-4 plugs, Dunlop K-70 tires. Oh yes, inlet and exhaust clearances were .003 and .005 respectively.
This bike is fitted with a wide-ratio gear box which clashes on the street but performs beautifully on the strip. Is this normal? (Castrol #30 is used.)
I would like to know how to time this more precisely and what you would recommend I do to get better performance? N. J. Woodbury Burlington, Vt.
We do not know what the Triumph distributors in the East offer to help their dealers; in the West, Johnson Motors supplies service bulletin 17-63, which gives a very comprehensive accounting of ignition setting procedures. In general, we would say that if you have this, or a similar bulletin, at your disposal, then problems would have to result from A) misreading the instructions or B) a manufacturing error. In any case, the trouble you are experiencing with tuning your Triumph can almost surely be traced to the ignition — which seems from the symptoms to be running somewhat retarded.
Presumably, when you say that the "factory prescribed routine" gives too much advance, you mean that the points are too advanced, relative to the alternator rotor, to produce a spark. You can go wrong by having the rotor indexed to the wrong dowel, and it is possible that the dowel holes have been improperly drilled at the factory. Try a different rotor and see if the problem clears itself. If so, the rotor can be sent to the distributors for properly indexed dowel holes. If not, then check through your timing procedure carefully.
As for the transmission-clash, this is probably resulting from a dragging clutch. On the drag strip, where everything is spinning furiously, merely easing the throttle will slip the box into the next gear. On the street, a little more help from the clutch is often needed. •
