Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127208
·~ . 1990 Yamahas ~ The return of the playbike . . F ro m the company that produced th e origina l low- cost pl aybike, th e DT-l , co mes two new downsized din bik es, th e RTI80 and RTlOO. " Finally there's a downsized dirt bike that has the looks of a real ra cer for th e pri ce of a playb ike," read s Yamah a's press release. The RTl 80 is a YZ look-al ike powered by an air-cooled, reed val ve, 176cc two-stroke single with a six- speed tran sm issi on . The simp le p o werplan t fea tures Yam ah a 's En ergy Induction System (YEIS). which co n sis ts o f a n expa nsio n cha mber between th e 24mm Mikuni carburetor and T orque Induction reed valve. When the reed val ve is closed by pressure from th e descendin g piston, the in take mixture flows into th e expansion tan k ra ther than sto pp ing abru ptly. as is the case in co nve nt io na l intak e syste m s. Yama ha clai ms th is smooths th e inta ke fl o w an d helps produce grea ter power. The RTl80 should be relatively easy to live with. It 's fitted with Yamaha 's Autolube oil injection system, which eliminates th e hassle of p re-mixing gas and oil, while the so lid-s ta te COl ignition is co m p letely mainten ance-free. Other features incl ude a tubular stee l, se m i-do u b le crad le fram e , leading-a xle fork. YZ-style Mono'cross rear sus pe ns ion with tr iangulated swinga rm and sin gle shoc k, drum brakes and full -sized, 2l-inch front and l8 -inch rear wheels with knobby tires. Fuel ca pacity is 3.4 gallons. In thes e troubled times, the RT's quiet mu£fler/spark arrester is indispensable. Avail able co lors are white or black. . For smaller riders. Yam aha is offering the RTloo. a furth er downscaled version of its sibli ng 180. The RT IOO's 97cc po werpl ant sha res many of its design featu res with the l80's engi ne, lik e its aircoolin g , T orque Induct ion reed valve, Au tolube o il inj ecti on and COl ignition, but th e 100 has one less cog , mak ing du e with a fivespeed transmission. The 100's running gear is also sim ilar to th e l 80's, with a tubular s tee l fram e a n d large-d iam et er whee ls with kn obby tires and drum brak es. H o wever , the suspension of the 100 is a bi t less adva nced : d ua l shock absorbers with five-way adjustable preloa d yield 3.2 inc hes of tra vel at the rear, whi le a telesco pic fork provides 4.4 inc hes of tra vel at the front. A sma ll ish 1.2-gall on fuel tank wi th YZ repl ica "radiator" shrouds The only all -new models in Yamaha 's 1990 lineup are the RT180 (above) and RT1 00 (left), two playbikes in the tradit ion of the original DT -1 . ,