Cycle World Service
CYCLE WORLD SERVICE
Cable lubing
I've encountered conflicting advice on tubing cables. I've been told that light motor oil is good, and other sources have recommended moly-based sprays. Can you solve this conflict?
Rick Kjarval Chicago, Ill.
First check to see if the cable should be lubricated at all, as several manufacturers advise against lubing Teflon lined cables. The information should be in the owner's manual or shop manual. If no lube is recommended and the cable feels sticky, flush it out with contact cleaner or a very light oil like WD40. For cables where lubrication is recommended, the key is to use a light oil, like a 5 or 10 weight motor oil, or in a
spray can, Bel-Ray 6-I. Light oils with moly ad ditives are fine, but stay away from chain lubes. They dry so tacky that they inter fere with smooth cable movement.
Alternatives
in your column Cycle World Follow Up (April, 1984), "Big Batteries," you stated, "What sizes and varieties of batteries are available, we
don't know." I do. The following is a list of batteries available to the Moto Guzzi owner when a new battery is required: Old style Moto Guzzis (Ambassador, Eldorado): Volkswagen Group 42; any Corvair bat tery; Sears DieHard No. 4310; Ford No. 10 LSN; John Deere No. AM 52050; John Deere No. TY6024; Montgomery Ward 22NL; and Exide AG. New style Moto Guzzis:
Autolite 1OLSN (Ford); GS CHD 4-12; DEKA-Outdoors man, East Penn Manufacturing Co., Lyon Stations, Pa. 19536; Western Power, G&W Corporation, Kent, Wash. 98031; J.C. Penny Survivor MF-42; YUASA Battery Company Yumicron #160-N24L-A. I'd like to see more lists or alternate/substitute parts for popular machines. Dick Morgan Phoenix, Ariz First, thanks for the useful information. Second, we'd b~ happy to print more such alternate lists. As they say in the magazines, contributions are welcome.
Suzuki carb rejetting
I own a 1982 Suzuki GS1 100EZ and am thinking about installing a Kerker pipe, K&Ns, etc. I com mented to my dealer that I was thinking of installing a 1983 airbox for the increased airflow over the stock unit.
My dealer then informed me that it was futile because my stock carbs cannot be rejetted. I nearly fell out of my helmet. Now, I know that with any aftermarket product you need to get the correct fuel/air ratio for best power and I can’t rejet my carbs?
Am I up the proverbial creek? What’s the deal with these carbs?
Hal Haskins Dothan, Ala.
The CV Mikunis on the GS1100 are rejettab/e, but your dealer can’t legally change them. While you can rejet the carbs (pilot and main jets are readily available), it’s so difficult to properly set up CV carbs without a dyno and an exhaust gas analyzer that you may not find it worth the time required.
There are several solutions to this dilemma. First, you can avoid changes that are likely to require rejetting, essentially any modifications to the airbox or intake system. Exhaust changes shouldn’t require any but minor carb changes: perhaps a slight richening of the mixture with the pilot air screw, or a one size change in main jets. Second, you could buy a kit made bv MV Enterprises (1323 Schofield Áve., Schofield, Wisconsin, (715) 3594921 ) that includes individual air filters along with all carburetor components that need to be changed to work with them, and complete instructions. The kit sells for about $150, and may be distributed by K&N as well as directly available from MV. We’ve had some experience with a prototype version, and a GS1100 with the kit carburetes well. Finally, if you plan to make major changes to your engine, you may find it easiest to switch to slide throttle carburetors for jetting ease.
Magna capacity
I have a 1982 Honda V45 Magna, and I would like to increase its load capacity because I use it for two-up touring. I have a Continental TK-44 tire on the rear and I’m also considering air shocks. Would the shocks help?
Alan Cargile
Adger, Ala.
They certainly would, as does the use of a tire with a greater load capacity than the stock tire. Keep in mind, however, that manufacturers set vehicle gross weight requirements by taking into account more than tire and suspension capabilities. They also have to make sure a motorcycle is stable while carrying its maximum load, that the
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brakes are still adequate, and that parts don’t break from the extra weight. If you venture much beyond the manufacturer's GVWR figure, you’re venturing beyond the point where the manufacturer says the bike is safe. You’ll have taken care of some concerns with tire and suspension modifications, -,but some caution is still advisable.
850 Triple defects?
# recently purchased a 1981 Yamaha $50cc Midnight Special. I enjoy the bike and its ride; however, as a new biker, a few questions are bothering me.
Was there a chronic problem that I am unaware of, or any special reason Yamaha stopped producing the three cylinders? Should I think about dumping this three cylinder for a twin?
George W. Fisher, III Mt. Ephraim, N.J.
The Yamahas Triples did have a chronic problem that no Japanese motorcycle model can survive: less than satisfactory sales performance. The de-
mise of old models and their rapid replacement with new reflect market demands more often than engineering defects. The XS750 and XS850 were sound machines. If you’re content with your Triple, keep it.
NSU parts
# am the owner of a NSU-Prima motor scooter (circa 1950). The scooter is in apparent good condition, however, it is badly in need of servicing. I am in desperate need of a service manual. Can you help?
James F Brace Buffalo, N.Y.
We’re told the NSU scooter parts and information expert is Al Nelson (154 Durward Rd., Akron, Ohio 44313).
Drop him a line and he should be able to help.
Jerky clutch
I was interested in your response to Scott Bury (March, 1984) regarding his lurching Ducati. I have a lurching Kawasaki KZ440 which has a serious clutch sticking problem. The engine often stalls when I drop the transmission into first gear after the bike hasn’t run for a day or so.
The real concern was damage to the engine/transmission, so I use a steel ring at times to hold the clutch lever pulled in overnight. The ring is slipped over the handlebar grip and pulled-in clutch lever, and this solves the problem.
Will leaving the ring on for an extended period harm my clutch in any way? I realize it keeps the clutch cable under tension, and the return spring compressed, but how about the throwout bearing?
Carl Anderson Dartmouth, Nova Scotia
Damage to the throw out bearing is unlikely, and the steady load shouldn’t hurt the clutch cable. Leaving the clutch disengaged for long periods may cause the clutch springs to sack, however. This would make the clutch more likely to slip, but unless you actually have clutch slippage problems, there’s no real reason to stop your clutch disengagement practice.
Tire test questions
^he other day I pulled out my October, 1983, Cycle World with the tire tests, and figured out the lateral acceleration and the acceleration due to stopping from 60mph. What puzzles me is that during cornering, the Continental tires >
could produce .78 g of acceleration which is below what a high performance car can pull, but when you figure out the deceleration during stopping, the tires produce 1.093 g. This is much greater than what a high performance car can produce. Also, the forces required to generate these accelerations are much higher than the numbers generated in the static tests. Can you offer any explanations?
Jeff Short
Sacramento, Calif.
The contact patch size may vary considerably between full braking and full cornering, which could explain some of the difference. The rest could probably be attributed to the greater ease a tire can be held close to its traction limit during braking (as well as the smaller penalty for exceeding the limit: a slight skid corrected by backing off the brake). It’s simply much more difficult to corner a heavy bike near its limits around a skid pad.
As for the differences between static loads the tires generated during our test and the actual loads during cornering and braking, there are two explanations. First, during braking, weight transfer onto the front wheel increases its traction. This wasn’t true for our front tire static test. Second, our static testing may not reflect real world conditions that accurately, and for that reason we put more emphasis on the other performance measurements during our testing.
Backfiring XT
i am having a problem with my 1982 XT550 Yamaha. It has a tendency to backfire on upshifts. As it does not do this when the choke is on, I suspect an intake leak. My dealer says that this is a tendency on the part of this model and that it is not a problem, but I’m not so sure. Although I have looked carefully I can find no leak, but I have a SR500 which I shift exactly as I do the XT and it certainly has never done this. I would think that with the intake system, Yamaha certainly would not take a step backward in technology.
Bob Peeples
Orem, Utah
You’re on the right track looking for something that makes the carburetion lean; the backfire is caused by a lean misfire. The backfire may be related to a problem common to all 1982 XT550s. The 1982 models supplied both carburetors with fuel from a single float bowl, and under some conditions the >
secondary carburetor didn’t receive enough, causing a lean stumble.
Yamaha fixed this in 1983 by supplying fuel to the secondary with an external line instead of a drilled passage in the float bowl. They also made a kit available so the fix could be supplied to the 1982 models. This fix might end your backfire problem.
If it doesn’t, look for other reasons for a lean mixture. Check out the float
level height, and check for any plugged jets. If it’s not either of these, the problem may simply be an idle mixture set too lean. Any Yamaha dealer equipped with Yamaha’s exhaust gas analyzer could give you a quick check on that. If your local dealer doesn’t have the equipment, you could try adjusting the pilot screw out half a turn or so.
Warped brake rotors
# own a 1982 GSI 100EZ Suzuki.
When I bought it, it had already had its front rotors and pads replaced twice under warranty. The original owner had much more opportunity than me to use the brakes hard as he lived in California with its winding roads compared to the flat, straight ones where I live. The local Suzuki dealer wasn’t surprised to hear of my bike’s rotor exchange as they had replaced “quite a few’’ under warranty. Is there anything I can do to retain proper brake lever feel and prevent further warpage, as there is a slight pulsation returning to the lever after only 1000 miles of light use? Would aftermarket brake pads such as Lockhart competition series pads help?
D. J. Minor
Champlin, Minn
Brake pads aren’t a solution, as the problem lies with the brake discs. Their manufacturing process leaves stresses locked into the discs. Then the high temperatures created by braking relieve the stresses, and the discs distort slightly to new equilibrium states. The cure is to take warped (and therefore stress relieved) discs to a good machine shop, and have the shop grind a few thousandths of an inch from the surfaces, so they run true again.
Slow throttles
In many of your tests you frequently comment on the power available by saying, “give it a handful of throttle and watch it go.” My problem is that on my 1983 GPZ1100 my wrist cannot phys>
ically move from idle position to wide open without rolling the grip in my fingers. Not only is this dangerous, as I must loosen my grip to perform this feat, but is sometimes impossible if I'm wearing thick gloves.
Why do manufacturers of such powerful bikes inhibit full use of the power available by requiring three hands to simply open the throttle completely? Is it a design requirement or regulation? I’ve found this condition present on many different makes.
Michael J. Spencer Santa Maria, Calif.
We measured the amount of movement required to fully open the throttle on several open class street bikes, and they all required about 90° oj throttle rotation. With that amount of rotation, it’s difficult to fully open the throttle if you’re holding the grip with an unbent wrist with the throttle almost closed; you have to hold the throttle further forward so your hand starts out rotated below the forearm, and ends up at full throttle rotated above the forearm.
Most people have over 150° of wrist movement, so with the correct hand positioning, throttle opening can be done without letting go of the handgrip Still, it can be a fairly clumsy operation, and pure race bikes often have throttles that require less movement. Why not on big street bikes? Less rotation would require more effort to overcome the return spring, but the main reason is in the power of the bikes. The manufacturers are reluctant to put quick throttles on bikes that already respond quicker than some oj their riders.
Follow-up follow-up
T"his letter is in response to your March, 1984, Follow-up column where you mention a couple of problems with the Suzuki GSI 100ES: side cover pegs and chain life.
I found that if you lubricate the side cover retaining grommets with WD-40 it keeps them from becoming sticky and making the side cover difficult to remove, thereby sparing the side cover pegs.
As for the chain, it was recommended to me by my Suzuki dealer that the chain should be run just on the loose side of the suggested tolerance. I currently ride a 1983 GSI 100E and have covered 16,000 mi. in a short 10 months. It has the original chain, and although the rollers are slightly loose, it has been adjusted only four times. I feel that it has plenty of miles left.
W. S. McIntyre Simi Valley, Calif. Eâ
