Tires

1. Why do my tires seem to wear so quickly?
Two of the most common reasons for premature tire wear are incorrect tire pressures (which we see constantly) and a tire compound inconsistent with your bike and riding style i.e. a soft tire compound on a touring bike.

2. I want to put bigger tires on my motorcycle. How can I tell what will fit?

No, you probably don’t want to put bigger tires on your motorcycle. They will probably make it handle worse, not better.

3. How do I break-in my tires?

If you take aggressive turns on new tires, you may dump your bike. New tires may have sticky or slimy goo on them; either mold-release compound from the manufacturer to make sure the tire comes out of the mold, or lubricant to let the tire slip more easily onto the rim. (Typically we recommend 50 – 100 miles before you can really push the tires) In any case, new tires a little greasy causing them to have limited traction. Take turns gently, slowly increasing your angle of lean. Slowly is the key: You always want enough of the contact patch to be on the broken-in section that you don’t lose it. Eventually your chicken-strips will disappear.

5. What’s the difference between radial tires and bias-ply tires?

The main difference between radials and bias-ply tires lies in their construction. Tires are reinforced with cords of steel or synthetic materials such as nylon or Aramid. In bias-ply tires, the fibers are wrapped in an X pattern between the beads; in radial tires, the fibers are wrapped perpendicular to the tread. Radial tires have more flexible sidewalls than bias-ply tires, and thus absorb road irregularities better and have a comparatively larger contact patch when leaned over. Because of the flexible nature of a radial, these offer higher mileage compared with a comparable bias-ply for a given rubber compound. Since they absorb small road irregularities better, they ride more comfortably and are less likely to be upset by groovy pavement.
While radial tires perform better than bias tires, some older motorcycles can’t be fitted with radial tires because of differences in rim profiles.

Engine, Transmission, Chain

1. How often do I need to change the oil?

There are several schools of thought on this. Some say you should change your oil every 3000 miles; others say every 6000 miles is fine. In any case, you should change it every 3 months.

2. Should I use petroleum-based oil or synthetic oil?

Yes. BMW doesn’t recommend synthetic oil until the engine is broken-in.

I notice that many bikes seem to require 10w-40 oil. Most manufacturers, of course, recommend their own specific name brand. We would be happy to recommend certain brands that we feel are best for your bike.

3. How often do I need to lubricate the chain? What should I use?

Every 600 miles or 1000 km, either spray wax chain lubricant or pour some gear oil on it.

How often do I need to check the chain’s tension? How?

Every 600 miles or 1000 km. Your motorcycle’s Owner’s Manual will have directions.
With most motorcycles, you check the tension with the bike on its side stand. The key is to have the suspension at the correct sag. (Best if owner is sitting on bike while it is adjusted)

You need to check the tension at several points along the chain’s travel around the engine and wheel sprockets. The tension should be set so that the loosest spot and the tightest spot are still within the slack tolerance specified in the owner’s manual. If the tightest spot is at the tightest allowed and the loosest is beyond the tolerance, then it’s time to get a new chain and sprocket set.

4. Do I have to replace the sprockets at the same time I replace the chain?

Yes. It’s likely that the sprockets are worn. Putting a new chain on a worn pair of sprockets will make the chain wear out faster—and replacing the sprockets without replacing the chain will sear out the sprockets. Do them as a set.

Fuel System, Exhaust

1. What grade (octane rating) of fuel should I use and why?

Use the minimum octane that does not cause your engine to knock. Anything more is wasted money.

2. Do I need to turn the fuel valve off to park the bike overnight or longer? Does it do any harm to leave it on?

If the float valve is in good shape and everything else is OK, no, you don’t have to turn off the fuel petcock. However, if anything isn’t perfect you’ll have, at best, gas all over the bike and the floor. At worst, you’ll fill one cylinder with gas and the other cylinder will fire when you try to start it and you’ll go into hydro lock and bend a connecting rod.

3. What does it mean to “re-jet” the carburetors?

Carburetors supply a mixture of gasoline and air to the engine. The gas comes out of little things called “jets” (usually a pilot jet, needle jet and main jet). If you modify your air box or exhaust to flow more freely, you get more air going through your system. This often means that there is not enough gasoline, so the engine runs badly. “Re-jetting” means replacing or modifying some of these jets so as to supply gasoline differently than stock, usually more gasoline than stock. If done correctly, this allows your engine to generate more power, run a little cooler, start and run smoother and get worse mileage.