The Service Dept
THE SERVICE DEPT
JODY NICHOLAS
POLARITY CHECK ALTERNATIVE
May I offer a simpler method for “Polarity Check”? This was shown to me a few years ago by an old Swedish mechanic, and the steps are as follows:
1. Cut a potato in half.
2. Place two copper wires of unknown polarity about a half-inch apart in the exposed white part of the potato.
The negative side will turn slightly green at the wire in a few minutes.
Roger Ritz Winnipeg, Canada
SEALED BEAM CONVERSION
Some I 1/2 or 2 years ago you published an article concerning changing the Lucas headlight bulb system to a sealed beam unit.
/ have a 19 70 Triumph Bonneville which blows the lower beam at the rate of one or two a month. If you have this article or the particular issue of your magazine, 1 would sure like to purchase it.
Maybe you could also tell me the correct way to adjust my rear chain so it is running true on the sprockets and the rear wheel is in line with the front. The procedure outlined in the owner’s manual is impossible to get the wheels to line up.
Charles L. Swoboda St. Louis, Mo.
Triumph has a solution to the blowing bulb problem which involves mounting the headlamp unit in rubber. The parts needed are two each of the following Triumph part numbers: F3814, F0967, F5228 and Fl-51. These are rubber washers of varying thicknesses, steel washers and two nuts.
The idea is to isolate the headlamp from as much vibration as possible by removing the unit and inserting rubber washers on each side of the headlamp mounting ears, snugging down the headlamp mounting bolts, and then screwing the nuts on the mounting bolts on the inside of the headlamp shell to keep them from loosening up.
Another alternative is to substitute a GH 6014 sealed beam headlight for the standard unit. The 6014 is a threeprong, high/low beam unit which gives a good spread of light and is easy to install. You'll need a standard threeprong. connector which will plug into the rear of the sealed beam lamp. This conversion will mean that you'll lose your parking light, but they aren't legal in many states anyway.
Ideally, the front and rear wheels should line up perfectly with the chain running true between the rear wheel and transmission sprockets. Sometimes this perfect state cannot be achieved, due to slight manufacturing errors, or perhaps to a slightly misaligned or bent frame or swinging arm. Repeat the procedure outlined in your instruction manual and try to get the wheels to line up. It's more important to have them tracking true than to have the chain perfectly lined up.
(Continued on page 24)
Continued from page 20
CARBURETOR ADJUSTMENT
My Honda manual says to balance the exhaust pressures on the right and left sides by adjusting the stop screws. Where can I get a gauge to do this? Auto supply houses don’t know what I’m talking about. Bike shops “don’t know.” Am I wrong in believing you’d plug one into the hack end of the tail pipe?
Bill Potter Lansing, Mich.
You neglected to mention the model of your Honda, but adjustment of all twin-cylinder machines using a carburetor for each cylinder is very similar.
First, make certain that the float chambers are free from dirt, and that the float levels are properly set. Next, check the ignition timing setting, the condition of the breaker points and the spark plugs, and finally the tappet settings. If the former items are not set correctly, it will prove difficult to adjust the carburetors to obtain smooth running.
If there is room between the carburetor air intakes and the frame (or air cleaner holders), you might be able to use a Uni-Syn gauge to check the vacuum produced by each carburetor. These gauges are little more than a sight tube with a float inside which rises and falls according to the amount of vacuum. Before buying one (they are available at many foreign auto supply houses), make certain that the orifice in the cover plate of the Uni-Syn is smaller than your carburetor air inlet.
If there isn’t enough room to use a Uni-Syn, follow the method outlined in your instruction manual, and pay careful attention to the sound that comes out of each tailpipe. It should be the same.
As far as I know, there is no gauge available to measure exhaust gas pressure that would be within the financial reach of the average motorcyclist. [Ô]
