Roundup
ROUNDUP
THE GHOST OF MOTORCYCLE FUTURE
There was a time, we're told, when there were no dirt and Street bikes. Just motorcycles. Most roads being unpaved at that time, any motorcycle, whether it was a BSA, a Husqvarna, a Moto Guzzi or a Harley, had to be able to handle all kinds of roads. These weren’t dual purpose machines, because there was only one purpose for a motorcycle: riding it.
As roads got better motorcycles, like cars, gained more road-hugging weight, which some riders discovered how to remove before they raced across the desert or across the forest. That was the birth of the dirt bike, even though the off-road versions were no differently equipped than all motorcycles had been at one time.
Although street and dirt bikes have grown apart, there is a common ground and it’s really a simple cliche: Racing improves the breed. Kinda catchy, right? Just remember, you saw it here first.
What this is leading to (yes folks, it is leading somewhere), is the benefit to street bike technology from off-road motorcycles. First air pressure was added to dirt bike forks, and then designers of street bikes found benefit in the idea. Now some of the leading dirt bike designs are moving away from high air pressure in the forks, but the idea has stuck with street bikes.
Aluminum swing arms have been used on motocross bikes the last couple of years and this has been followed by the aluminum swing arm on the Suzuki GS1 100.
Single shock rear suspensions, led by the Yamaha monoshocks, but now used by all the Japanese off-road bikes, are appearing on street bikes this year. Yamaha is using systems on the 750 and 920 V-Twins that are similar to the design of the dirt bike rear suspensions. Same with Honda. Originally the Pro-Link rear suspension was designed by Honda’s New Racer department, worked out on the works motocrossers, and now it's used on the CBX and the GL500 street bikes. The street bikes even have their own reasons for the single shocks, it making saddlebag mounting much easier.
Most of the innovations transferred from dirt bike to street bike has been in suspension and chassis, because competitive dirt bikes have used two-stroke motors while street bikes have become predominantly four-stroke.
Motorcycle development hasn’t stopped. It hasn’t slowed down. There are going to be more dirt-bike ideas used on street bikes. Things like the big fork tubes and beefy triple clamps being used on the latest off-road machines. And street bike maintenance could take simplicity lessons from dirt bikes. Why can’t street bike wheels be removed as easily as those on the Suzuki PEs?
If dirt bike design can influence street bike thinking surely best idea is the simplicity and light weight required of the motocrossers.
A 250 lb. YZ465 with lights and shortened suspension could make a heck of a street bike.
MORE MONTESAS
For the rider who doesn't want a common motorcycle, who thinks Huskys or Maicos are ordinary, Montesa has announced a range of 1981 models. Yep, Montesa is still around, and making more than just trials bikes.
Naturally the Cota 349 trials bike is still produced, essentially the same as it was last year. A smaller Cota, the 200, with a full cradle frame and a much different motor, is also offered.
For motocross there’s the 414 VG and the 250 VG, with 12 in. of suspension travel front and rear from the Marzocchi leading axle forks and piggyback reservoir shocks. The 250 has an all-new chromemoly frame and comes with Pirelli Pentacross tires.
Enduro models, in both 250 and 360cc sizes are available. Unusual for contemporary enduro machines, the 360 still uses straight-leg Marzocchi forks. The 250 is more modern with its leading axle forks, and both bikes come with enough lighting to be street legal in many areas.
Information on the 1981 Montesas is available from the importer, Cosmopolitan Motors, Jacksonville and Meadowbrook Rds., Hatboro, Penn. 19040. (215) 672-9100.
THE BIKERS' CAMPAIGN
As part of its new political awareness, the American Motorcyclist Association in 1979 formed a political action committee with the aim of helping candidates who might give a sympathetic ear to biker problems and concerns. All perfectly respectable and privately funded.
Also successful. AMPAC entered the 1980 campaigns with a fund of $ 13,000, of which $12,000 was contributed to 49 can-» didates for the U.S. House and Senate. Of those 49 candidates, 42 won in November. AMPAC’s concern was with riders and
riding and candidates were chosen on their records and on where they would work in Congress, that is, on committees dealing with transportation, energy, public* lands and resources. Party labels weren’t as issue, although 27 of the winners were Republicans and 25 were Democrats.
AMA isn’t claiming any credit for the’ wins. The money probably helped, but nobody claims the bikers overturned the old order by themselves.
What it does prove is that AMPAC and the voters were on the same side.
ON WISCONSIN
Two bits of good news from Wisconsin. One is in the form of a pamphlet, issued by the Wisconsin Department of Transportation and given to new riders and drivers. The title is "Equal Rights On The Road." The introduction mentions the increased number of motorcycles and mopeds and reminds drivers that twowheelers are equal under Wisconsin law. The booklet advises care when making turns, warns that cycles may be difficult to see and reminds that cycles have rights-ofway just like other motor vehicles.
Equally helpful, perhaps moreso be-1 cause the audience is less likely to be thinking of the subject, was an article in “Insight,” the Sunday magazine published by the Milwaukee Journal. The* cover story shows a biker narrowly avoiding a car door flung open in the bike’s path and the picture caption says “That cyclist has rights, too.”
The article goes on to say what we all wish the public was willing to hear, that motorcycles are legitimate, have rights* and deserve to not be crowded off the road.
None of this is news to us bike nuts. But to have the non-motorcycle press and the all-vehicle state officials telling the story to people who might not otherwise have thought of the subject is bound to help us« all.
ITALJET ARRIVES
When Italjet hired world trials champ Bernie Schreiber away from Bultaco it didn't have a competitive trials bike. Within a couple of months, though, Schreiber was winning four world trials competitions in a row, something that had never been done before, and he did it on an Italjet trials bike.
Now the Italjet 350T is in production, and it’s available in the U.S. Last time the Italjet 350 Trials was mentioned here, there was no report from the U.S. importer about availability. According to the factory, the 350T will be available through Italjet U.S.A., 13148 Saticoy St., North Hollywood, Calif. 91605. (213) 982-2000.
Specifications on the Italjet aren’t available yet, though the photos available indicate it’s much like the other good trials bikes, the Montesa Cota and Bultaco Sherpa. It uses no frame tubes under the engine to increase ground clearance, has the exhaust routed inside the frame tubes and shocks where it’s not likely to burn a rider, and uses short travel suspension that looks much like that on the Cota. Italjet
has made a broad variety of two-stroke motors for years, and the 350T uses a
trials-tuned version of an existing Italjet motor.
INSIDE YAMAHA'S YICS
Here's a diagram of the Yamaha Induction Control System (YICS) used on the Seca 550 and Seca 750. Besides the usual intake ports, the YICS system has four inter-connected subports. The subports intersect the main ports between the valve guide and valve seat, at an angle. The main port draws through the carburetor, as usual, but the subport draws from the intake tracts of the other cylinders, through the other subports. On the intake stroke, mixture is drawn into the cylinder through the main port and the subport. Because the subport is about one-fourth the diameter of the main port, and yet is ► exposed to the same amount of cylinder vacuum,the mixture traveling through the subport travels about four times faster than the mixture in the main port. When the high-velocity stream of mixture from the subport intersects the flow of mixture from the main port, it swirls the mixture - entering the cylinder. The swirling distributes the mixture more evenly in the cylinder and improves cylinder charging.
What it all means is more engine efficiency and better fuel economy without lowering performance.
