RZs rule

Old Bike Australasia - - LETTERS TO THE EDITOR -

With the ben­e­fit of hind­sight it seems ob­vi­ous that the post-war Bri­tish mo­tor­cy­cle in­dus­try lived on its past glo­ries for too long. While Nor­ton, Tri­umph and BSA sol­diered on pro­duc­ing sin­gles and twins, their Ja­panese coun­ter­parts forged ahead pro­duc­ing re­li­able, af­ford­able small­ca­pac­ity bikes with in­creas­ingly so­phis­ti­cated en­gines. With­out doubt the CB750 re­leased in 1969 was a land­mark ma­chine that paved the way for the in­cred­i­ble per­for­mance ca­pa­bil­i­ties of mod­ern 1000cc sports bikes. Mr Moor (‘John Bull rules’ OBA 41) should set aside his rose-coloured glasses for a mo­ment when wax­ing lyri­cally about his old BSA and other Brit bikes of the 1960s while pour­ing scorn on Ja­panese ma­chines. Per­haps he has for­got­ten the oil leaks, dodgy electrics, sundry parts that were prone to go miss­ing in ac­tion, and numb­ing vi­bra­tions as­so­ci­ated with “Bri­tish bull­dogs” of those days? In any case the mon­strous al­le­ga­tions he makes against the Yamaha RZ 350 (“these ghastly death en­gines equipped with Dr Kaaden en­hanced lawn­mower mo­tors, front ends ap­par­ently sprung with bags of marsh­mal­lows …”) sim­ply can­not go un­chal­lenged. A di­rect de­scen­dant of the Yamaha TZ 250/350s rac­ing bikes, the wa­ter-cooled 2-stroke twin pro­duced 59.1 bhp at 9000 rpm and was a gi­ant killer in its day. The RZ was equipped with an in­ge­nious elec­tronic power valve sys­tem (YPVS) that largely over­came the 2-stroke Achilles heel of nar­row power bands and smoky ex­hausts. YPVS made the en­gine much more tractable for road use while cat­alytic muf­flers helped in re­duc­ing ex­haust pol­lu­tion. I own a 1983 model RZ that I used for com­mut­ing, tour­ing and some club rac­ing in the 1980s be­fore stor­ing it away while I was over­seas. Fol­low­ing a re­cent restora­tion it’s back on the road and I can vouch for the fact that it’s still a bril­liant lit­tle bike. Ad­mit­tedly fuel econ­omy is not a strong point, es­pe­cially if rid­den with some, ahem, ex­u­ber­ance. But rest as­sured Mr Moor, an RZ can go around a cor­ner in ex­cess of 6,000 rpm with­out ty­ing it­self into knots. Ad­mit­tedly a sporty light­weight may not suit some­one more at­tuned to the lan­guorous rhythm of many old Brit bikes but in mo­tor­cy­cling, as in other walks of life, the old adage still ap­plies, dif­fer­ent strokes for dif­fer­ent folks. In the face of tight­en­ing emis­sion con­trols and noise re­stric­tions, 2-strokes have of course largely dis­ap­peared. The ban­shee wail of high revving 2strokes, the sound­track of mo­tor­cy­cle rac­ing through the 1970s and ‘80s, is a fad­ing mem­ory. Un­for­tu­nately mod­ern fuel in­jec­tion tech­nol­ogy and elec­tronic con­trol sys­tems have not been used to de­velop a new gen­er­a­tion of clean burn­ing 2strokes given the well-proven ad­van­tages that this en­gine de­sign of­fers – an out­stand­ing power-toweight ra­tio and sim­plic­ity. Roger Butterwort­h Coogee NSW

For more in­for­ma­tion con­tact: [email protected]­tee.com

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