Service
SERVICE
Len Vucci
RE-TIRED GOLD WING
I bought a set of Lester mag wheels for my Honda Gold Wing last year, and had to choose a rear tire for the 16-inch wheel. I chose a 5.10-16 Pirelli primarily because its outside diameter was very close to the 17-inch Bridgestone that came with the bike.
I am now in need of a new rear tire, and was considering Goodyear's 16-incher (the one used on Kawasaki's 900 LTD). How ever, the Goodyear's low-profile design is about 1-inch less in diameter than my Pirelli.
Do you think this size difference would make an annoying increase in rpm and if so, how much? How about the decrease in ground clearance, or effects on the ge ometry of the bike? Maybe you can think of a tire that would be more suitable for me.
Anything you can come up with will really be appreciated.
Steve Witthoff Canoga Park, Calif.
Engine rpm will increase only about five percent, which shouldn't be annoying at all.
In fact, the extremely long-legged GLJ000 will probably respond well to the change.
A decrease of one inch in diameter lowers axle height by only one-ha/finch. This is a fairly small change, and shouldn `t produce any noticeable effects on handling.
MYSTERY OIL
In past issues of CYCLE WORLD, mention is repeatedly made concerning HD-315 oil.
Can you inform me where and how this oil can be obtained? There's not a bike shop in Michigan that's heard of it.
Keith Lucia Sterling, Mich.
Not surprising. The lubricant is made by Texaco, and was never intended to be used in motorcycle forks. But don't run down to your local service station to buy some. We use the oil only as a laboratory constant when testing the forks on the dyno, then replace it with a commercialfork oil. In this manner, different forks can be directly com pared without introducing another variable, viscosit~; which has a pronounced effect on damping rates.
HD-315 has a viscosity of approximately 10 at room temperature, and is the Saybolt (S US) viscosity designation. This has re cently given way to the metric designation, Centistoke (cSt) viscosity. In future issues of CYCLE WORLD, you will find the metric designation, which is HD-68.
AFOUL OF THE LAW?
The tip on how to convert to a sealed beam headlamp (March 1977) camejust in time for spring. I have a 1973 Triumph Bonneville and finding headlight bulbs for it was impossible. I installed a sealed beam and it works like you wouldn't believe.
I've been thinking about renewing my subscription to your magazine and after that tip there is no question about it. I'd like to tell other Triumph owners that it does work and not to be afraid to use the sealed beam, because for once in their life they'll be able to see where they're going.
Thank you again for a brighter outlook on riding.
Dennis Daly Schenectady. N.Y. continued on page 26
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It has been brought to our attention the conversion to automotive sealed beams may be contrary to the letter of the law in some states, California for one. We would not knowingly recommend that any law be disregarded. (The sealed beam on my own 1971 Bonnie does work very well indeed.)
BUFFALO DUMP
I ride a 1975 Suzuki GT750, watercooled bike. I have never had to add any water to the coolant system and two-up riding is great with this machine. The only problems I have had are a seal leak at the drive sprocket when new and a fork seal leak a short while later.
I suggest that anyone who owns a GT750 should inspect the plastic oil line on the CCI lube system from the tank to the pump. Mine split at the pump connection and dumped all the oil. Examination showed the line to be embrittled. Thank goodness it happened at night in the garage and not on the highway.
Russ Magers Paris, 111.
Thanks for a worthwhile tip which may help keep the Water Buffalo off the list of endangered species. Owners of other twowheeled animals might also benefit from your experience.
CERIANI FORK KIT
I read “The Service Department” in April’s issue with interest and dismay. Interest, as usual, and dismay that you were unaware of the fact that we have the Ceriani kit for Honda 550s.
As the exclusive U.S. importers and distributors of Ceriani products, we’ve maintained stocks of this kit since mid1976 and have experienced gratifying sales ever since.
The kit has a suggested list of $79.95 and can be obtained through dealers across the country (we do not sell direct to the public).
Thank you for your attention.
Roger B. Weston
Accessory Distributors, Inc.
175 Fair St.
Palisades Park, N.J. 07650
MINI FIX
How can I get more power out of my Yamaha YZ80C? Also, how can I improve my stock forks?
John A. Haynes Decatur, 111.
We receive scores of letters requesting information on engine performance modifications, and wish we could provide an answer to each of them. Unfortunately, allotted space in “The Service Department ” precludes our offering any but the most general replies. Rather than deal in genercontinued on page 30
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alities, we suggest you check through advertisements for performance parts and write the manufacturers for information. Many decisions can he made on the basis of priceno small matter even for a mini.
We can help you with the suspension problem, though. Number One Products has recently introduced a kit which fits most mini-racer forks. It alters the damping from the stock 50-50 compression rebound to rates which are more suitable to the bike’s potential.
BUZZER REBUTTAL
You printed a letter from me in your April column and titled it “Turn Signal Buzzers for BMWs.” In response to your note following the letter, I listened to a Mallory Sonalert at a local electronic store and found it unacceptable. It is not loud enough and it is not waterproof. If you mount it inside the headlight shell you won’t hear it for sure!
David M. Winters, M.D.
Reseda, Clif.
It never occurred to us that the Sonalert might not be waterproof. Southern California gets very little rain, but several heavy mists and foggy mornings failed to diminish its sound. It is not as loud, as embarrassing, or as personally offensive as a Honda buzzer, but when we installed one on a Honda 750, the Sonalert could easily be heard.
MISSING YZ-D
I recently purchased a new YZ400D. and I'm having a lot of trouble getting it to run smoothly on the bottom end.
It blubbers and cuts out all the time. In the March issue you stated your test machine ran better down low than a DT400 tested earlier.
Could it be my carburetor? If so, please tell me the jet sizes used in the bike you tested.
Mike Coop Caldwell, Idaho
The carburetor is most likely at fault. But before tearing it out and apart, check the ignition timing and spark plug, and make sure the proper gas/oil mixture is being used.
Check the carburetor next. Obvious problems such as loose jets and bad gaskets should be eliminated first. Jet sizes and needle positions should correspond to your owners’ manual, but this is merely a starting point. The bike should run well with only basic carb adjustments, but a jet change may be in order. That process is relatively simple in nature, but would require much more space than available here. We invite you to consult the carburetor article in our January 1977 issue for the necessary information. [5]
