The Service Department
THE SERVICE DEPARTMENT
JODY NICHOLAS
NON-LEADED GASOLINE
Being the owner of two Hondas, I am concerned about air pollution. I would like to use non-leaded gas, but I recently read an article staling that no-lead gasoline burns valves prematurely, and only stellite-tipped valves will resist this.
My question is: is this so, and if it is, what can the average hike rider do?
Chuck Sleavaj Chicago, III.
It is true that non-leaded gas causes premature failure in the valve area, but not because of valve burning. Rather, the exhaust valve seats have a tendency to “pound in” if there is no lead in the gasoline. This is because the lead acts as a cushion between the valve and its seat. Stellite is usually found at the end of a valve stem to reduce wear between the rocker arm and the stem.
Some bike riders will find that several of the new low-lead regulars will run satisfactorily in their four-cycle engines without retarding the ignition timing or lowering the compression ratio, but most machines tend to prefer leaded high-test.
Two-cycle engines are another story. Many of them will run well on nonor low-lead fuels because of their rather low compression ratios. Many manufacturers of two-cycle motorcycles recommend premium gas because of the tendency of the oil. which is burned with the gas in the combustion chamber, to reduce the octane rating of the gasoline. In fact, with a copious supply of oil going into the engine, the gasoline’s octane rating is reduced drastically and combustion knock can occur. But, with many of today’s advanced two-cycle oils, the fuel/oil ratio can be lowered to 40:1 or even “thinner,” and combustion knock is not a problem. The non-leaded gas and small amount of oil keep the engine from becoming carboned up, and spark plug fouling is reduced markedly.
The best thing the “average bike rider” can do about reducing air pollution is convince his friends to buy and ride motorcycles and leave their huge, smog-producing sedans in the garage.
HOT LIGHTNING
/ purchased a 1970 BSA Lightning in June of this year. It now has 1400 miles on it, and I’ve had problems of severe pinging or detonation since about 500 miles. This pinging is accompanied by, in my opinion, severe overheating. The dealer says it doesn’t overheat, but the carbs have so much heat transferred to them after about JO miles that one can’t touch them. The exhaust pipes, however, show no signs of discoloration. The timing, carburetion, and valve adjustments have been checked by both myself and the dealer and all are correct. Also, several viscosities of oil and different brands of premium fuel have been tried, but to no avail. Could you make any further suggestions?
I am considering installing the oil cooler that is stock on the Rocket Three. Is this feasible? Would the scavenge pump on the Lightning have sufficient volume for this?
William Lee ABO New York, N. Y.
Overheating is almost always caused by either improper ignition timing or a lean fuel/air mixture. There is, of course, a provision for timing the Lightning with a strobe light by using the pointer inside the primary chaincase. However, it is conceivable that the pointer is slightly off, so that using it would cause improper timing.
The easiest way to check for this is to use the static timing plug in the front of the crankcase. This plug locates the crankshaft at 34 degrees BTC. Insert the plug and see if the pointer lines up exactly with the mark on the generator rotor. If so, there are other checks to make.
Another cause of the overheating could be that the ignition advance springs are of incorrect tension, but this is usually not the case.
BSA Western has found that it helps to raise the carburetor slide needles one notch to riehen the mixture in the l/4-to-3/4 throttle range, and sometimes it is necessary to go up a size or two on the main jets. A one-step-colder spark plug seems to help, too.
Of course, it is important to make sure that there are no air leaks between the carburetors and the cylinder head.
An oil cooler is a good idea for summer riding, and is easy to install. We recommend the unit available from Paul Kinch, 5 Cardiff Rd., Luton, Beds., England. A complete cooler kit costs only S31, including airmail from England. It’s a good idea to replace the ferrules on the rubber hoses with hose clamps, however.
ROAD TEST GRAPH
I read your mag and all the others as soon as they hit the stands and sincerely think CW is the best, especially the road tests. I’m 14 and am saving for a Suzuki T500-III. I have about six mags with tests on it. My school has a subscription to CW and 1 saw that the October issue had a test on the big Suzuki. Naturally, I hit every store in Terrace looking for it. 1 got one finally and read it cover to cover several times, especially the road test on the Suzuki. 1 definitely think your specifications page is tops in the industry. 1 was looking close at your performance chart and noticed something I didn’t get. Under performance you state that at 7000 rpm in 5th gear the bike will turn 116 mph. Then you show on your chart that the bike shifts out of 4th at 103 mph at 7000 rpm and accelerates to roughly ¡08 mph at 7000 rpm, and this holds as top? Considering this happens on another test in the issue, it probably isn’t a mistake on your part, but on mine. Could you please explain how I should read this.
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I also noticed you said gear ratios were 13.75, 8.58, 6.38, 5.22, and 4.79 to 1. All the other books say 2.5, 1.56, 1.16, 0.95, 0.87 to 1. Is there an option of lower gearing for faster acceleration?
Curt Gand ini Mount lake Terrace, Wash.
You’ve brought out a couple of points which I feel certain are puzzling to other readers too. I’ll explain how we derive the material on the graph from the specifications and performance figures we receive from testing a machine.
Running horizontally along the bottom of the graph is the time in seconds. On the left-hand side is the speed in mph, and across the top is the rpm by 100s.
Using the Suzuki T500-111 road test chart as an example, there is a dashed vertical line between 6000 and 8000 rpm on the top line. This corresponds to 7000 rpm, which is the T500’s red line, and also the rpm at which it develops its maximum power. With other machines we use the red line because some produce their maximum horsepower at engine speeds which are less than the maximum safe engine speed.
By taking the final gear ratios, we calculate the machine’s top speed in each gear, at red-line rpm. Then, beginning at the lower left-hand corner of the graph, a line is drawn to intersect the vertical maximum rpm line. Note that the third diagonal line, which corresponds to third gear, intersects the dashed vertical line at 85 mph, which is the machine’s maximum safe speed in that gear.
You'll note that at the top of the data page, under the performance column, the computed speed in top gear is 116 mph at 7000 rpm, and you can verify this by following the fifth diagonal line to the 7000-rpm dashed line. However, right above that you will see that the machine’s actual top speed was 106.40 mph through the electric clocks, which corresponds to 6450 rpm. This is because the overall gear ratio in top gear is fairly “tall” and the machine can’t pull all the way to 7000 rpm. It was mentioned in the road test text that the T500’s overall gear was a bit too high, and that it could be lowered by substituting a 14-tooth countershaft sprocket for the standard 15-tooth item.
We publish the final overall gear ratios on the specifications side of the data panel because we feel that they are much more meaningful than the transmission’s internal ratios alone. Internal ratios really don’t relate to anything until the primary and secondary reduction ratios are known, from which the final ratios are derived.
TAKEN FOR GRANTED
In regard to a letter from A..I. Cox in the Service column, August issue, Mr. J. Nicholas advised washing parts in gasoline! This practice is extremely hazardous under all circumstances, and not in keeping with your usual good advice to motorcyclists.
As a professional fire fighter, I have seen severe burns, indescribable suffering and extensive property loss from the misuse of gasoline. A quick check with the Fire Prevention Bureau of the Long Beach Fire Dept, should convince you that gasoline should only go into gasoline tanks. I am also sure that any oil company would advise you the same. This product is so common that the average person uses it without thinking, thereby doubling the hazard!
At the risk of sounding like a “preacher, ” I would like to see you print an article on safe procedures for fueling motorcycles during races and outings. You may save a customer’s home or shop. Better still, you may save a customer.
Milton T. Hyde Stockton, Calif.
You are quite correct concerning the volatile nature of gasoline and the hazards it presents when used as a cleaning agent. Your advice is well taken. Certain Gunk compounds, kerosene, and certain of the ligroin-variety solvents, such as Stoddard solvent, are less likely to ignite under ordinary working conditions than gasoline.
Fueling a hot motorcycle is always a risky business, and especially during races. The best method I’ve seen for refueling is the one which Kawasaki Motors C'orp. adapted to their H-1R. It is a variation of the method used to fuel jet aircraft, but as such, it is much more costly than the average motorcyclist could afford.
