Service

SERVICE

Paul Dean

Virago hand warmer

I used to own a Gold Wing, which had a liquid-cooled engine and a temperature gauge, and now I’m interested in buying a Yamaha Virago, which has an air-cooled engine and no temperature gauge. What’s bothering me about possibly owning this bike is, how will I know when the engine is getting too hot? Besides burning my hands by touching the engine, is there a simple trick or some gizmos that could prevent the engine ever getting to that critical point? Raymond Jubinville

Montreal, Quebec, Canada

With rare and infrequent exception, motorcycles with air-cooled engines never have been equipped with temperature gauges-and for good reason: They don’t need them.

Liquid-cooled motorcycles usually overheat when something malfunctions in their cooling systems. And because those systems are rather complicated, lots of things could go wrong that can lead to overheating. The water pump can fail, the thermostat can stick, and coolant can be lost as a result of leaks in the radiator, the hoses, the head gasket and numerous other joints and fittings in the system.

Air-cooling systems, on the other hand, have no mechanical or electrical components to fail. So, if an aircooled engine overheats, it usually does so because its engine has gone drastically out of tune in one of only a few ways that can cause excessively high operating temperatures. When this occurs, the engine also runs so poorly that its erratic performance usually serves to inform the rider that something has gone wrong-which is largely what a temperature gauge does anyway.

So, don’t worry about the Virago’s lack of a temperature gauge. Provided that you don’t run it at high rpm for long periods while sitting still in 100-degree weather, the air-cooled engine in the Virago is far less likely to overheat than that of any liquidcooled motorcycle-including your old Honda Gold Wing.

ZX wanderbike

My 1989 Kawasaki ZX-7 is really starting to annoy me. A few months ago, I took it to the local shop to have new tires put on. While it was there, they noticed that the steering-head bearings were loose, so they adjusted them. Ever since, the bike doesn’t want to go straight ahead. It wanders a little to one side or the other, kind of like a car that needs a front-end alignment. I’ve taken it back to the same shop, and they claim the bearings are properly adjusted. I’ve tightened the swingarm-pivot nut and all of the bolts on the front end, and I’ve even checked rear-wheel alignment using the method you described in one of your previous Service columns. Nothing so far has helped. Is it my new tires or is something else wrong? Jeremy Eisman East Moline, Illinois

It ’s not your tires. Either the steering head bearings are adjusted too tightly—despite what your dealer says-or they ’re detented, which means that tiny dents have formed in their races. Either way, the net result is to offer just enough resistance to your normal steering inputs to cause the bike to wander slightly.

When steering-head bearings are too loose—which was apparently the case with your ZX-7 before taking it to the shop-riding over bumps makes the front fork shake back-and-forth. This, in turn, causes the bearing rollers to bang back-and-forth inside their races. If the looseness is not soon corrected, the constant impact between rollers and races will either put flat spots on some of the rollers or hammer small dents in the races-or both. Because the vast majority of a bike s road time is spent going straight, the detenting usually occurs at the point where the front end is aimed straight ahead.

To check for tightness or detenting, prop the bike vertically with the front wheel off the ground, then see how easily the front end moves from side to side. Once the handlebar is turned about halfway to one side or the other, the front end should practically flop the rest of the way itself. If it doesn’t, the bearings are too tight. And if the bearings are detented, you ’ll feel a slight resistance to turning when the wheel is aimed straight ahead.

If the bearings indeed are detented, replacement is the only solution. But curing a tight-bearing problem is simple: Adjust them until the front end flops side-to-side easily and no freeplay can be felt in the bearings when you grab the bottoms of the fork legs and pull them back and forth.

ET, phone Homer

1 have a 1968 Triumph, a 500cc T100C, that originally had one of Mr. Lucas’s infamously unreliable energytransfer (ET) ignition systems that used no battery. I got tired of constantly fooling with it, so I replaced the ET alternator, ignition coils and all the charging-system equipment with equivalents from a Lucas battery-ignition system, including the 12-volt battery. But now I can’t get the thing to run properly. It starts, idles and runs at lower rpm reasonably well, but it sputters and backfires and runs weakly at higher rpm. Do you have any suggestions about how I might solve this problem?

Homer Creft Tucson, Arizona

Yes. Swap your bike s original energy-transfer point-cam/spark-advance assembly for one from a 500cc Triumph with a Lucas battery-ignition.

In an ET ignition system, the alternator generates the primary voltage in the coils, and does so in a way that requires the point-cam lobe to open and close each set of points very quickly. The battery-ignition coils are wired differently, however, and require a point cam with a much-longer duration that allows only one set of points to be open or closed at any given time. In addition, the ET ignition s advance mechanism provides only about half the spark advance required by the battery ignition. □