Service
SERVICE
We welcome your technical questions and comments, and will publish those we think are of interest to our readers. Because of the volume of mail received, we cannot return any personal replies. Please limit your “Service” letters to technical subjects only, and keep them as brief as possible. Send them to: “Service,” CYCLE WORLD, 1499 Monrovia Ave., Newport Beach, Calif. 92663.
BSA SUSPENSION
I own a 1974 BSA B50 MX and am very interested in modifying the suspension. Your May, 1979, issue carried an article testing the CCM 600 which uses B50 engine tooling, etc. Do you know if the swing arm and fork/triple clamp assembly will fit my frame? If so, what about wheel and hub assemblies? Please send me the address at CCM of someone knowledgeable in these matters.
James W. Hamilton Burkeville, Va.
CCM does not recommend the use of their suspension components on the BSA B50 MX. Their swing arm and front fork assemblies are designed specifically for the CCM frame, which has different eg, steering head geometry and suspension travel provisions than the BSA frame. Martin Horn, importer of the CCM suggests that buying a used CCM (or, better yet, a new one) would provide more eco-
nomical and satisfying results than trying to adapt new CCM suspension pieces to the MX. He says the best improvement in B50 suspension can be made by extending the swing arm 1 in., moving the lower shock mounts 6 to 7 in. ahead of the rear axle, and installing a good set of aftermarket forks, making sure they allow the bike to remain level. He warns that excessive rear suspension travel on the MX can cause chain snatch that is very hard on the gearbox.
CCM does make a full set of engine and gearbox parts which are directly interchangeable with your engine, including a complete crank assembly, a four-valve head kit, and a very strong three-speed gearset. You can get more information from CCM, Rt. 1, Huntley, III. 60142.
750F REARSETS
While I love my 1980 Honda 750F, I wish it were equipped with the rearset pegs and
lower, CBX-style bars that are standard on the European CB900. Is it possible to order those parts? What else, other than the bars and pegs, is needed? Assuming that one has all the proper pieces, will they simply bolt on with no further modifications? Finally, what would this conversion cost? If it is physically impossible or just too expensive to use Honda’s parts, do you know of any other companies making rearsets for the 750F?
In the June issue’s article on security devices, you stated that even a full-rev burnout couldn’t break the Stop & Lock you fitted to a Suzuki 750. But last fall, in a similar test, one of your competitors rated the device unsatisfactory. Seems that the one they fitted to a Gold Wing shattered when the bike was simply pushed forward. Can you or Stop & Lock explain the discrepancy? Thank you.
Giff Nickol Townson, Md.
Honda is planning to market a Europeanstyle handlebar and rear set kit for the 750F through Hondaline “later this year." No price available yet. They say the kit will bolt right on to the F with no other modifications. Tom Hayner Racers Supply, 6959 Van Nuys Blvd., Van Nuys, Calif. 91405 (213) 781-6386, sells a $67.95 rearset kit which includes footrests, levers and bellcranks with Heim joints, but no mounting brackets. They say the kit is adaptable to the 750F, but not a direct bolt-on, so some hole drilling may be necessary. For handlebars, we have used CB400F bars and Superbike and Graham’s Sheet Metal bars (at different times, for different riders) on our resident 1980 750F long-term test bike, no modifications required.
As to your other question, we ordered a Stop & Lock for a Suzuki 750 because that was the test bike for our theft project. The Stop & Lock worked fine on that bike; it was solidly made, well-finished, and virtually unbreakable. So we had to base our conclusions on the model we tested. Stop & Lock tells us that approximately 45 of their early production run locks for the G LI 000 managed to get packaged and sent out before Hhey were properly heat treated. One of these apparently fell into the hands of another magazine as a test lock, much to Stop & Lock's dismay. They have since tried to recall all the others. Anyway, the lock we tested worked.
CYCLE TOWING
I have a 1978 GS550 which I will have to move across country within a year. I plan to purchase or rent (if possible) a trailer and plan to pull it with my 1978 Fiat 128.
I would like to know if you could recommend any dealerships and/or companies who might deal in motorcycle trailers. I would additionally like to know if U-Haul or any similar companies rent motorcycle trailers, precluding my purchasing one.
Ed Fauss
Cascade, Md.
We don’t know of any rental agency, such as U-Haul, which provide trailers strictly for motorcycles, however most rental outfits •have a small, general purpose open trailer which works fine for bikes. (One of our staffers, evicted from his last place of residence, in fact towed his motorcycle to southern California using a Fiat 128 and a UHaul.) Most motorcycle trailers are manufactured and sold regionally because of the cost and inconvenience of shipping them any great distance, so your local motorcycle shops are the best bet for checking out price and quality on trailers.
An alternative to the trailer is a bumper carrier. This is a sort of front wheel cradle which bolts to a normal trailer hitch, holds the front wheel off the pavement and allows most of the bike’s weight to ride on the trailing rear tire. The motorcycle drive chain should be removed for towing with this type of carrier. You'll put some added miles on your rear tire and wheel hearings, but it’s cheaper than buying a trailer. Two Wheel Accessories sells one called the Hitch-Hiker for $79.95. Their address is 344 Jericho Tpke., Mineóla, N.Y. 11501. The HitchHiker has a lifting lever that makes it possible to roll the tire into the cradle at ground level and then raise the bike. A less expensive model, where you do the lifting, is called the Trail-A-Bike; suggested list is $49.95, and it’s distributed by Hap Jones, 1040 Rock Ave., San Jose, Calif. 95131. You can check with them for the name of your nearest dealer.
A third suggestion is to keep your eye on the classified ads. Used cycle trailers appear with some regularity in most metropolitan papers, generally priced anywhere from $100 to $300.
COMING NEXT MONTH: TEN BEST BIKES OF 1980
KZ CLUTCH
After reading your article on the new Kawasaki KZ750 in your June, 1980, issue I am wondering about your statement on page 32 where you said, “The clutch is th^e same size as that of the KZ650, there are the same number of plates and they're made of the same material. What’s different is the clutch springs. They’re stiffer OHJ the 750 . . .” Does this mean that these springs could be used on the 650 to make a better street clutch for a modified KZ650?
Also, what is the largest tire that will tit on the 650? The factory tire is a 4.00H-18.
Chet R. Boisen LaPorte City, lowa¡
The stiffer 750 clutch springs will fit the 650 and provide heavier spring pressure for high-performance use, as will KZ1000 springs, because all three Kawasakis use the same clutch but have different amounts oj power to handle. The KZ650 clutch, however, has proved nearly indestructible ir^ drag strip use, even with stock springs in place. So unless you are planning modifications that will yield a big power increase, different springs may be unnecessary. If you do need heavier springs, several companies, such as S & W, R.C. Engineering and Barnett, make heavy-duty clutch spring kits. These are available through most performance-oriented Kawasaki dealers.
We have used a Dunlop 5.10-18 K81 on the rear of a KZ650 with no clearance problems. This tire has a 5 in. cross section, which is about as wide a tire as the KZ will safely accept without clearance problems. Different brands of tires have varying cross section widths, even though the numbers are the same from one brand to another. So whatever tire you choose, it’s best to measure the cross section and use approx. 5 in. (5.10 in. is okay) as a limit.
LUBING THE RD
I own a 1974 Yamaha RD 350 and it’s great bike. My Yamaha has Autolube, and somehow I don’t trust it. Would it be worth my time to disconnect it and mix my oil with my gas when I fill up? I bought the bike used and it is in rough shape. Also, what would you suggest for a mixing ratio?
Grant D. Hurrell Neepawa, Man. Canada
The Autolube setup on the RD is normally a sound, reliable system for lubing the engine, and we suggest you leave it in place. It meters the oil according to both throttle opening and engine speed, which cuts back on smoke and oil consumption eft lower speeds, as when you’re riding arounû town. It also makes gas stops a lot easier because you don’t have to worry about pre^ mix ratios or accept an oil of questionable quality from a roadside gas station. Roadracers sometimes remove the Autolube system to save weight and to eliminate the slight power drain of the Autolube pump.
"They are concerned only with full-throttle operation, however, and are able to tailor ihe premix ratio specifically to that rpm range. Also, mixing the right oil in the correct ratio is a lot easier with a 5-gal. can at Ihe race track than it is in your tank at a gas station. Yamaha did a lot of work on the Autolube system to make life easier for the two-stroke street rider, so unless you’re gearing up for all-out track performance, you should find the system reliable and quite a bit more convenient than going with premix.
O-RING OIL
I own a ’79 Honda CB750F with a rubber Ö-ring rear chain. Is it safe to use aerosol chain lubricants on this chain? My owner’s manual says to use regular gear oil and that «commercial chain lubes may have solvents in them that could damage the O-rings. What’s the lowdown?
Gary Kozak Petaluma, Calif.
Several companies now produce aerosol lubricants safe for O-ring chains; Kal-Gard, PJ-l and Bel-Ray are a few we know to be safe. Look for the inscription “Safe for Citing chains” on the side of the can and you won 7 go wrong.
HARLEY STARTER
I wonder if you could answer a technical query about my 1977 Harley-Davidson XLT; the operation of the starter motor reties on both a solenoid and a starter relay, and it would appear to me that this latter item could be disposed with.
Basically, why does it need a two-relay switch system? Is the answer that the handlebar ignition button is not of sufficient capacity? Should this be so, could you vecommend a heavier duty ignition switch, or button, that would allow the elimination of the relay.
John Hassall Manchester, England
Your suspicions about the ignition button are correct. The starter solenoid simply draws more current than would be practical to run through handlebar wiring and a compact starter button. To eliminate the relay and switch power directly at the handlebars tiould require heavy-gauge wire and an industrial duty switch, both of which would increase resistance in the starting circuit gnd place a heavier draw on the battery. If the battery were low, starter operation would be impaired. Generally, any time you can consolidate electrical components in the Vicinity of the power source and avoid running line current through distant switches you are ahead, not only in reliability but in the saving of weight and material. If the starter relay is causing no problem, the system is probably best left wired as it came from the factory.
COMING NEXT MONTH: TEN BESTHIKES OF 1980
WRENCHED SPOKES
I purchased a 1978 Honda XL1 25 about nine months ago from the Honda dealer in town. When I bought it, the bike had 108 miles on it and it now has about 2000. My problem is that the spokes on the back wheel have been snapping off at the hub. I only use the Honda for trail riding and farm purposes. I would appreciate any help you can give me.
Mark Waibel
New Ulm, Minn.
Dirt bike spokes can loosen up considerably when a new machine is first ridden, and, unless they are tightened at that time, may begin to fatigue and break. If you have already broken a few spokes, chances are the others are also weakened and in poor shape. Rather than replace one or two spokes and chase the problem around the wheel (having to remove the wheel and tire each time), your best bet is to have the wheel relaced with all new spokes, then check and tighten them more frequently. An added help in extending spoke life is to wire the spokes together where they cross and touch one another. A short length of stainless steel safety wire looped around three times and twisted tight works well. The twisted ends, as a precaution, should be bent inward so you don’t cut your hands on the sharp wire when working around the rear wheel or washing the bike.
If you continue to break spokes with normal trail riding, check the rear suspension to make sure you don 't have a bent shock or swing arm, or some malfunction that prevents the rear suspension from properly absorbing shock loads. E8
