Quick Shifting
Quick shifting
SERVICE
I like to do a lot of drag racing, which goes fine until I have to shift. Then all hell breaks loose—I just can't seem to shift quickly enough. Someone into drag racing recommended that I use an air shifter or an electric shifter, so I wouldn't have to use the clutch except for taking off. I hadn't heard of either before. Could you tell me where I could get one of these, and which would be best? With one of these shifters installed, could I still ride my bike on the street and around town comfortably?
Matt Beckner Fort Knox, Kentucky
An electric shifter momentarily kills the ignition when the shift lever is moved. That removes engine load from the transmission momentarily, allow-
ing a shift to be performed without backing off the throttle or using the clutch. Most electric shifters also have a switch controlling their operation; with the system off, engine and shifter operation is absolutely normal, allowing easy street use.
An air shifter combines an electric shifter along with an air cylinder to actually move the shift lever; basically, it reduces shifting to pushing a button mounted on the handlebars. As such, it's less streetable than an electric shifter. Electric shifters for most large Kawasakis, Suzukis and Yamahas are available for about $180 from HP Products, 311 Chestnut St., Santa Cruz, California 95060; (408) 4273625. Air shifters can be purchased from M*R*E, 625 Pinellas St., Clearwater, Florida 33516; (813) 4435330.
Building a Superbiker’s mount
I’ve seen the Superbiker's race on ABC’s Wide World of Sports, and also some clips on Moto World showing Eddie Lawson's winning 490.
I’m interested in building or buying something like these machines, but I haven’t seen any ads or reports on these bikes. If building is necessary, where can I get the right parts?
Michael Pinkert
Palatka, Florida
Converting a big-bore motocrosser into a Superbikers machine is relatively easy. First, wheels and tires need to be changed. For the actual Superbikers race, 19-inch dirt-track tires (Carlisle, Continental, Goodyear or Pirelli) are used. If you want to use these for an authentic look, you 'll have to lace compatible 19-inch rims to your motocrosser's hubs.—An y good wheel shop (such as Buchanan 's Frame Shop, 629 E. Garvey Ave., Monterey Park, California 91754; [818] 280-4003) should be able to supply the necessary rims and spokes. As an alternative, Pirelli MT40 dualpurpose tires would work nearly as well as the dirt-track tires, and wouldn 7 require w heel changes.
Second, the motocrosser's suspension travel should be shortened to about 9 or 10 inches at both ends, with suitably stiffer springing. Either White Brothers (11750 Seaboard Circle, Stanton, California 90680; [714] 8951991) or Works Performance (8730 Shirley Ave., Northridge, California 91324; [818] 701-1010) should be able to assist in these suspension modifications.
Further modifications will be necessary if you want to build a fully competitive machine. More horsepower wilt be required; we suggest you turn to Harr y Klemm at Klemm Research (2761 E. Regal Park, Anaheim, California 92806;[714] 630-9420) to find it for you, as he has built fast and reliable motors for Superbikers racing. Also, more than a stock motocross front brake will be required. Kosman Specialities (340 Fell St., San Francisco, California 94102; [415] 8614262) could supply a suitable 13-inch disc and matching caliper.
Horex parts
I have a Horex 350 motorcycle and have been looking for the address of a Horex dealer (I think it’s in New York) to purchase parts. As I understand, the owner of the dealership, Mr. Stern, died some years ago, and the business was sold. Do you or any of your readers know of a source for Horex parts?
Aime F. John, Jr.
Manchester, New Hampshire
No, we don V know of a Horex dealer. But if anyone reading this would send us the address of a Horex parts source, we'll run it in a later Service column.
Better YZ490 jetting
Fm the proud owner of a leftover YZ490K. As with all the early 490s, mine came jetted way too rich. After months of testing, I have arrived at what I consider the best jetting specs. My bike now runs strong enough to stay with current openclassers in full throttle drag races. These specs should work on all 490s that are running too rich.
Main jet 430 Jet needle 6F16 Needle clip postiion 4 Needle jet Q-4 Slide cutaway 3.0 Pilot jet 35 Air screw 1.75 Float height 30mm Yamalube R at 40:1 NGK B8ES
Tampa, Florida
“Dirt Bike Mike” Hubbard
Tampa, Florida
VMpass these recommendations on untested, and with just a note of caution: Large displacement two-stroke Singles are often running close to their thermal edge, and rely on rich jetting to keep piston temperatures under control. Jetting that gives best power may lead to seizures if you ride under conditions that allow you to run sustained full throttle for more than a few seconds at a time. So while these settings may work for most woods or track riding, they may not be suitable for desert use. In any case, the first sign of a problem in an open class bike will be pronounced pinging, and that 's a clear indication you'll have to run richer jetting or less compression.
Ducati info
I have a 350 Ducati—I think it’s a 1969, and it has desmodromic valving. This is my first cycle ever and it’s another one that has been found and rescued. I work on my own cars, but I need names and numbers of Ducati parts sources in my area.
Lee Abernathy
New York, New York
Cagivci North America is the distributor of Ducati motorcycles and parts. Contact them at 700 W. 190th St., Gardena, CA 90248; (213) 538-9337 for a list of the Ducati dealers in your vicinity. 0
