Service
SERVICE
FJ1100 wheelies
As an owner of a FJ1100 motorcycle, I would like to be able to lift my front wheel off the pavement without popping the clutch. Would a header allow me to do this?
Darwin Gore Gouverneur, New York
We're not completely sure of the wisdom of making throttle-only wheelies easier, but an exhaust system change by itself is unlikely to have that effect. Physics dictates that only a few things will make wheelies easier: a higher or more rearward center of gravity, or more forward thrust at the rear wheel.
Moving the motorcycle's center of gravity higher or farther rearward is neither easy nor in most cases very desirable. That leaves increasing peak forward thrust. But because peak thrust occurs in first gear at the engine's torque peak, typical engine modifications that make more power by raising the torque peak up higher in the rpm range (with no actual torque increase) will make wheelies no likelier; even though they will make the motorcycle faster and quicker. Conversely, modifications (such as bigbore kits) that increase engine torque will make wheelies more likely by improving low-speed acceleration.
One very simple change will have the same effect, and require no engine modifications: lower gearing. Lower gearing multiplies the engine's torque at the rear wheel, thus increasing acceleration at low speeds and enhancing the wheelie tendency. If you 're willing to put up with a lower top > speed and increased engine buzzing at cruising speeds, a simple change of sprockets will give you all the throttleonly wheelies you could ever want.
Oil viscosity
I recently had a certified Honda dealer service my motorcycle. I told him I use Castrol 20w50 GTX motor oil. I have consistently used this viscosity oil since I purchased my Honda CM450C, and that was
10.000 miles ago. The service manager told me I should be using 10w40 oil. His reasoning was that 20w50 burns 35 degrees warmer than 10w40, and he pointed to my blue-colored exhaust pipes as evidence. (As I explained to him, my pipes are blue because for 30 miles this spring I ran with a partially clogged carburetor, hence a bad fuel/ air mixture and a higher burn temperature.)
So, which viscosity of motor oil should I use, and why?
Michael Andrew Uhl
Buffalo, New York
According to Honda, for any temperature over 15 degrees Fahrenheit, either 10w40 or 20w50 is recommended. And your service manager is wrong about the 35-degree temperature difference between weights; the two oils are like/y to be so close in operating temperatures that it would be difficult to measure the difference.
As far as one viscosity being better than the other, that would depend on operating conditions. For short trips around town (underfive miles) where the oil never comes up to full temperature, the 10w40 might give more engine protection by flowing more easily while cold. Under harder; more sustained use, and especially in hot weather, the 20w50 might be better. But as long as you 're using a quality oil of either viscosity, the difference isn't worth losing an y sleep over.
Steel sprockets vs. nylon
I own a 1982 GS750TZ Suzuki. The bike is set up for touring and is used for that as well as commuting. I don’t thrash my bike, and it rarely sees redline; in fact, it’s unusual for it to turn over 6000 rpm. I put about
12.000 miles a year on it.
The time has come to replace the chain and the sprockets, and I’m> considering a nylon rear sprocket.
An independent mechanic that I use said the nylon sprocket is a good idea. He also suggested that, with my riding style, I should replace the original-equipment 630 chain with a 530-size chain. He said it would be lighter, quieter, and run smoother. However, the local Suzuki dealer insists that I should stick with the 630 size and a steel rear sprocket.
He claims that the 530 chain and/or the nylon sprocket will not hold up.
Who’s correct, the dealer or the mechanic?
Samuel V. Camden
Elk Grove Village, Illinois
They both have a point. The dealer is correct in claiming that the 630 is an inherently more rugged chain than a 530; it ought to give a longer chain life on a Suzuki 750 than any other chain. And we’ve heard of numerous cases in which nylon sprockets didn ’t stand up to hard use, especially when subjected to drag-race style starts or power shifts. But the mechanic also is right in saying that a 530 chain is quieter and perhaps more efficient, as well as noting that with your riding style, the nylon sprocket would likely be adequate. But as to which combination will actually last longer, that ’s impossible for us to say without having tested the exact combinations you ’re proposing. We’d suggest that if you’re unhappy with the mileage you received from your current chain, that you might consider the mechanic's suggestion simply as an experiment. It might lead to better results. And if it doesn V, well, at least you'll have learned something.
CBX connecting-rod strength
I have a 1979 CBX that I’m rebuilding. I’ve been told the rods in the CBX are weak. Can you tell me if there is a heavy-duty or highperformance rod available without going to R.C. Engineering’s Golden Rod?
Mitchell R. Harris
Tyler, Texas
mUMPSsMUSs
CBX connecting rods aren 't exactly weak; rather, they were designed to take stock engine loads, and not much more. If you are rebuilding your CBX with stock components, there is no need to change rods. But if you 're installing a big-bore piston set, or camshafts and valve springs that will allow the engine to rev significantly higher, you'll want better rods.
Kaz Yoshima, of Ontario Moto Tech, has as much experience as anyone in building high-output CBX engines, and he recommends Carillo steel rods for much-modified engines. (Yoshima also counsels that many forged, big-bore pistons are very heavy, and impose particularly large loads on rods; lighter cast pistons make life easier on rods and bearings.) Ontario Moto Tech usually stocks the Carillo rods, and its address is 6850 Vineland Ave., Unit 16, North Hollywood, CA 91605;phone (818) 766-7101.
Correct oil volume
I own a 1983 Honda CM450A Hondamatic. In the section pertaining to changing the engine-transmission oil, the service manual specifies 3.5 quarts of oil. When I use this amount, the oil level on the dipstick goes over the full mark.
I have called my local Honda dealers for advice. One has closed, and the other said, “Fill just to the top mark.” That’s less than three quarts in my machine.
Could a Hondamatic possibly take a different-length dipstick, or does the quantity of oil required for my machine differ from the amount used in a standard transmission?
A. Tosiano
Burlington, New Jersey
Your dealer is correct, and the dipstick is the proper indicator that your CM450A has sufficient oil. There are several possibilities for a discrepancy between the recommended 3.5 quarts of oil and the amount you 've been able to put into the engine before the dipstick reads full.
First, the 3.5-quart capacity assumes the engine is completely devoid of oil, a condition that won 't exist unless you change the oil filter as well as drain the sump. Even then, a few tenths of a quart may be trapped in the engine. Secondly, the dipstick must be used as Honda intended: simply pushed back into its hole to make a measurement, without being screwed in. Finally, the fresh oil must be allowed to fill up all the cavities vacated by the drained oil, and particularly the torque convertor of your bike. The only way to do that is to add the fresh oil until it's at the dipstick full line, and then run the engine for a fewω minutes. Afterwards, you 'll find the oil level has dropped, and you'll be able to add some more. But even if you 're never able to fill the engine with exactly 3.5 quarts, don't worry;just trust the dipstick.
More on countersteering
In reference to Paul Dean’s June Editorial, “Left is left, right?,” I am still confused as to exactly what is '*• going on. Could you please give me some good written references on this subject?
Forrest R. Boozer
San Luis Obispo, California
Unfortunately, we don't know of i any good accounts of countersteering. But while countersteering seems a confusing idea, all it really means is i that the way the handlebars are turned to start a turn is different than their position while in the turn. When going around a constant-radius right-hand i corner, a motorcycle's front wheel is turned very slightly to the right—not as much as a car's front wheels would be turned, but at least in the same direction. But arriving at that steady cornering state is very different from automotive practice.
To initiate a right-hand turn on a motorcycle, the motorcycle's front wheel is first turned to the left. Why? Because a motorcycle has to lean to turn, and countersteering to the left steers the front wheel out from under the motorcycle, causing the motorcycle to lean to the right. So the basic sequence for the right turn is this:
Turn the bars to the left to start the i turn, and then let them swing back to the right as you settle into a steady cornering attitude.
Many (if not most) motorcyclists are not consciously aware of this sequence, and find it slightly incredible. But countersteering is very real, and is the only way to make a motorcycle turn quickly. EH
