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OILHEAD OIL LEVELS BEST USED BII(E PANIGALE VICE VERSA TAILLIGHT ISSUE
RAY NIERLICH
JUST BUY MORE BIKES
Q: I have owned a 2003 BMW R1150GS since it was new, and * it has been my favorite bike of many I’ve owned. I recently had to have it rebuilt (at 63,000 miles) after oil-related piston failure, which was a surprise to everyone. It was always maintained well and run on synthetic oil since break-in. One interesting fact: My bike has never held anywhere close to the recommended amount of oil. It has always dropped the oil level to close to a quart less by putting it into the airbox and/or burning it off on start-up. Several very experienced BMW mechanics have told me it is not unheard of on this bike, but I am concerned, as it still has this characteristic since being rebuilt. I have been told that as long as I can see a bit of oil in the sight glass, all is fine, and that adding more oil will result in what I described before. Time for a new bike? Or just ride it with an eye on the oil level?
MIKE MITCHELL SAN FRANCISCO, CA
A Mike, it’s always time for a new bike. But this doesn’t mean you have to sell your GS. Man does not live by one bike alone. An oilrelated piston failure comes as a bit of a surprise. These Oilhead BMWs are typically quarter-million-mile engines.
If it is pushing oil out the breather, either it is overfilled or it is building up crankcase pressure. First, check the engine breather hose for any kinks or obstructions. It runs along the right side under a plastic cover. Second, are you positive the engine isn’t being overfilled? Be sure you are only adding 4 quarts at the oil change. To get the most accurate level without overfilling, put in 3.5 quarts or so. Then run the engine for at least a few minutes, shut off, and wait three minutes. With the bike level, read the oil level in the sight glass. Top up the oil to the middle of the sight glass red circle. The circle on the glass from top to bottom is about one pint.
If you still haven’t found the problem, a leak-down test should be performed on your engine when at operating temperature warm. Leakage should be less than 5 percent for each cylinder. If
it is more, add a few drops of oil to the cylinder through the spark plug hole. If it goes down to 5 percent or lower, your rings are allowing too much bio why.
OIL VS. WATER TEMP
Does oil temperature run about the same as water temperature * on liquid-cooled bikes? I’ve seen oil temps of 300 degrees and climbing in heavy summer traffic on air-cooled machines. Not healthy. If the water temp is away from the red and kept stable by the fan, can I assume the same for the oil? Any direct correlation with the two readings?
LARRY HELVITE CYCLEWORLD.COM
A Sort of, sort of, and sort of.
Oil temperatures do follow B the coolant temperatures, but oil temperatures are slower to rise and slower to fall. Modern streetbike coolant temperatures typically run at 195 to 205 degrees Fahrenheit. Oil temperatures need to be at least 200 degrees to evaporate condensation. In normal operation, the oil temperature will continue to rise ideally to a maximum in the 225-degree range. Oil temps can climb higher yet especially when in high-load, high-rpm, and high-ambienttemperature conditions. Nervous time begins around 250 degrees for conventional oil and about 300 degrees for synthetics. Which is why separate oil coolers are common on racing machinery. Oil is expected to do more of the cooling in air-cooled engines. They are worse than liquid-cooled engines in maintaining sane oil temps, especially in low-airflow conditions, as you have noted. Fortunately for us, today’s oils are better than ever, so failures from high oil temps are almost unheard of.
FOLLOW
FOLLOW THE AXLE
I’ve owned mostly lateros and ’80s midsize streetbikes, and a good number of them (and several dirt bikes) have had their front axle located in front of the fork, not on the bottom as most are now. I believe I’ve seen a Yamaha (Seca?) with the front axle actually behind the fork.
¿%G0T A MECHANICAL OR TECHNICAL PROBLEM with your beloved ride? Perhaps we can help. Contact us at cwservice@cycleworld.com with your questions. We cannot guarantee a reply to every inquiry.
BEST USED BIKES YAMAHA RZ350
YEARS SOLD 1984-'85 MSRP NEW: $2399 ('84)
BLUE BOOK RETAIL VALUE: $4300
BASIC SPECS A two-stroke, power-valveequipped 347cc parallel twin with 26mm slide-valve Mikuni carbs, oil injection and six-speed transmission. A steel-tube frame with an aluminum swingarm rolls on 18-inch wheels with triple disc brakes. Its simplicity allowed it to be a light 371 pounds with the 5.2-gallon (!) gas tank half full.
WHY IT’S DESIRABLE: The RZ350 is the most modern and last legal street-going two-stroke sold in the US. In the first full test, we said ourjuly 1984 cover bike rated a “perfect 10” on the fun scale.
On Jerry Branch’s dyno, the stock RZ350 made 42.7 hp at 9,000 rpm; redline is 9,500. Below 6,000 rpm, the engine “doesn’t make enough power to pull the skin off a bowl of rice pudding,” read the test, but power came on strong after 6K. Hey, welcome to the fun zone! The RZ350 turned in an impressive quarter-mile time of 13.19 seconds at 99.22 mph, and that was with the 0E catalyst exhausts. Fun and nimble handling are improved with fitment of modern tires on those classic ’80s wheels. A surprising number of these bikes come up for sale at reasonable cost, but original, low-mileage examples in excellent condition can go for double blue book. Aftermarket parts support remains very good.
THE COMPETITION: Not really. Yamaha’s own RZ500 V-4 two-stroke was sold in Canada, and many made the gray-market journey south, but prices are quite a bit higher. Kawasaki’s Ninja 600R was the most high-performance middleweight of the time, but it was significantly heavier.
ASK KEVIN
QiOn several
■ occasions, you’ve mentioned the handicap Ducati has with regard to weight bias and engine placement. The engine is heavy in back, where the crank and transmission are. So why not turn the engine around? Crankshaft toward the front, one cylinder pointing up, the other back. Admittedly, not trivial to do, but Ducati has plenty of resources.
GEORGE GRENLEY CYCLEWORLD.COM
A »In the early 1990s, a major motorcyclehandling problem was “squat and push.” During off-corner acceleration, if thebackofthemachine squatted down from acceleration weight transfer, the front end would become too light to steer and the bike would “push” (fail to hold the line and run wide).
Öhlins studied this and wrote a math analysis that was circulated to teams. It showed how
to use two other chassis forces to oppose squat: (1) the rear wheel tries to “run under” the bike, tending to extend the rear suspension; and (2) chain tension because it does not act parallel to the central plane of the swingarm, generates a tangent force, also tending to extend the swingarm.
With this knowledge, teams quickly made swingarm pivot locations adjustable so they could vary the antisquat force. Ducati, however, continued to pivot its swingarm on a lug integral with the gearbox, making pivot position adjustment impossible. Ducati’s stiff rear spring overcomes the squat force, but it causes a more rapid loss of tire properties. This problem plagued Ducati’s Superbike racing effort foryears.
If, as you suggest, the gearboxwere placed ahead of the engine crankshaft for a more advantageous forward weight distribution, some system of chain
idlers would have to be implemented to restore the necessary sprocket/ pivot relationship. Very possibly this could be achieved. The tendency in racing, however, is to make small, incremental changes that are easily reversed if they fail to meet their objective.
Ducati, for marketing reasons, feels it must use the “signature” 90-degree cylinder angle, despite its packaging bulk. Sometimes, companies must make choices. When Yamaha hired Valentino Rossi, Masao Furusawa gave him four prototype bikes to test-two with 90-degree cranks and two with 180-degree cranks, with one of each pair having Yamaha’s signature five-valve Genesis cylinder head and the other a conventional four-valve head. Rossi went quickest with (and liked) the four-valve engine with a 90-degree crank. The result?
MotoGP titles for Rossi and Yamaha in 2004, 2005, 2008, and 2009.
-Kevin Cameron
What’s the thinking here? I see how dirt bikes can take advantage of the slightly longer fork, but why were streetbikes configured this way?
L. DILL LEEDS, AL
A Streetbikes were made this
way for the same reason as dirt bikes. Engineers back in the ’70s and ’80s were attempting to improve rigidity of the fork while maintaining or increasing travel. By putting the axle ahead of the fork stanchion tubes (or behind in at least one failed experiment), they could increase the overlap between inner stanchions and outer sliders without reducing the clearance between the top of the sliders and the bottom triple clamp on full compression. They also increased tube diameters and beefed up triple clamps. Tubing strength goes up exponentially with diameter. So every small increase in diameter makes a significant improvement in strength. Today we have inverted forks. This puts the larger-diameter tubing in the triple clamps and also allows for more overlap between the sliding parts while maintaining travel.
MY TAILLIGHT STAYS ON!
I bought a 2006 Suzuki DR650SE. The bike runs great, but I have * one problem: Once in a while, when I turn the bike off, the taillight stays on. I’m pretty sure it’s not the brake light. If I move the brake controls around, nothing happens. The only way I can get it to turn off is to turn the key on and off again. Sooner or later, I’ll forget to check it and end up with a dead battery.
JONATHAN D.SUMMERFIELD ALLENTOWN, PA
A You have figured this one out.
On your bike, the taillight and B license-plate bulb are supposed to be on when the ignition switch is in the “park” position. Be sure you aren’t accidentally turning the switch past “off” to “park.” The contacts in your switch may be defective and are keeping the parking light on when the key is in the “off” position. You can verify this with a voltmeter or a test light at the switch connector. You should see voltage at the brown wire (taillight) when in “park” and none in “off.” CTU
