Kawasaki KR250

Old Bike Australasia - - CONTENTS -

The tan­dem twin

It was 1975 when Kawasaki stunned the Grand Prix pad­dock by un­veil­ing their in-line (“Tan­dem”) twin cylin­der 250, a mo­tor­cy­cle that was des­tined to be­come one of the most suc­cess­ful GP bikes ever, and which was joined soon by a 350cc ver­sion that was equally fond of the podium.

The KR250 was not an in­stant suc­cess – it took un­til Assen in 1977 for Bri­tish rider Mick Grant to score the first GP win – but from then on there was no look­ing back. Grant took a sec­ond GP win at Swe­den later in the year, but this was just a taste of the dom­i­nance en­joyed by the Big K in the fol­low­ing years.

Of course, Kawasaki had ven­tured into the quar­ter litre class be­fore, with the A1R, an­other disc valve racer that ap­peared in 1967. It was quick too, but frag­ile and gen­er­ally no match for the Yama­has that dom­i­nated by sheer weight of num­bers on grids world­wide. Un­like the A1R, which was avail­able for sale to the gen­eral pub­lic, the KR250 was a works racer through and through, al­though se­lected ma­chines were made avail­able to im­porters in Europe and USA, as well as in Aus­tralia via Team Kawasaki Aus­tralia run by Neville Doyle with rid­ers Gregg Hansford, Mur­ray Sayle and Rick Perry. Prom­i­nent South Aus­tralian Kawasaki deal­ers Bolton’s also

se­cured a KR250 (and later a KR350) for their sponsored rider Paul Cawthorne.

On the world stage, South African Kork Balling­ton bat­tled might­ily with Hansford in 1978, se­cur­ing both the 250 and 350 ti­tles, which he re­tained the fol­low­ing year. Then came Ger­man An­ton Mang, who took the 250cc cham­pi­onship in 1980, the 250/350 dou­ble in 1981, and the 350 in 1982.

By 1984 Kawasaki had opted out of Grand Prix rac­ing fol­low­ing their dis­as­trous foray into the 500cc class with the KR500, but then pulled a sur­prise move by an­nounc­ing a new KR250 (launched lo­cally as the KR250A1)– not a racer, but a road-go­ing model aimed squarely at the 250cc Pro­duc­tion class, one of the hottest cat­e­gories in the world, es­pe­cially in Aus­trala­sia. Its tar­gets were the Suzuki RG250 and the Yamaha RZ250, and in the vi­tal weight stakes, the 134kg Kawasaki sat be­tween the two, at 131 kg and 145kg re­spec­tively. All three pro­duced near iden­ti­cal power – around 24.5 kW at the rear wheel.

The Tan­dem twin con­cept was es­sen­tially a pair of 125cc sin­gles mounted one be­hind the other on a com­mon crank­case, with cranks con­nected by large gears. This lay­out per­fectly suited ro­tary valve in­duc­tion directly to the crankcases via dual carbs, pro­duc­ing a very slim ma­chine with a low cen­tre of grav­ity. The new KR250 road­ster how­ever, had lit­tle in com­mon with the GP ma­chines other than the ar­range­ment of the cylin­ders. Un­like the racer, which had both pis­tons ris­ing and fall­ing to­gether for 360º crank tim­ing, the road­ster used a 180º set up, achieved by hav­ing the right side clutch gear split, with the halves be­ing held to­gether by a shock-damp­en­ing sys­tem. The rear crank and cylin­der sat above the gear­box keep­ing the over­all pack­age short and com­pact.

In­duc­tion was by a com­bi­na­tion of ro­tary disc valves and reed valves, mounted on the right side in­board of the pri­mary drive gears – the rac­ing KR250 had the carbs on the left. The fuel and oil mix­ture en­tered the crankcases via Mikuni flat slide car­bu­ret­tors, through the reed valves and then to the com­bus­tion cham­bers via trans­fer ports. Whereas both the main ri­vals, Suzuki and Yamaha, opted for square bore and stroke of 54mm x 54mm, Kawasaki set theirs at an over-square 56mm x 50.6mm, pro­duc­ing a higher rev ceil­ing for a given pis­ton speed. The cylin­der head was a one-piece unit, with sep­a­rate cylin­ders. Cool­ing was by wa­ter, with the pump driven from the left side of the front crankshaft. Also un­usual was the ex­haust sys­tem, with the front cylin­der’s ex­pan­sion cham­ber run­ning un­der the en­gine, and the rear ex­it­ing from un­der the seat, sur­rounded by an ex­ten­sive heat shield for rider and pas­sen­ger com­fort.

Chas­sis-wise, the KR250 also stood alone. Box­sec­tion steel tub­ing was used through­out, with the frame it­self made in three pieces. The ma­jor part com­prised the steer­ing head and the widely-spaced top sec­tion of straight tubes. The lower cra­dle

sec­tions bolted to a pressed pivot for the swing­ing arm, with the rear sub-frame bolt­ing to this and to the main frame, sup­port­ing the seat and rear mud­guard. The swing­ing arm it­self car­ried tri­an­gu­lated brac­ing for the bell crank which con­nected to the sin­gle gas-filled rear shock ab­sorber, mounted hor­i­zon­tally and it­self con­nected to the chas­sis un­der the front cylin­der. The sus­pen­sion unit was ad­justable for spring pre-load and re­bound damp­ing, with the pre-load ad­just­ment via a knob at knee height on the left side. The damp­ing ad­just­ment was done by a four­po­si­tion ad­juster stick­ing out of the belly pan on the left side. Pi­o­neered on their suc­cess­ful mo­tocross bikes, Kawasaki la­belled this sys­tem ‘Uni­track’.

Up front sat a set of con­ven­tional forks fit­ted with Kawasaki’s AVDS (Auto Vari­able Damp­ing Sys­tem) with ad­justa­bil­ity via air caps and a vari­able an­tidive. Un­der each leg sat a knob which could be ad­justed through a range of four set­tings. The legs them­selves were joined by a sturdy brace which also sup­ported the front mud­guard. Al­though in the mideight­ies the trend was to­wards the now-uni­ver­sal 17-inch front and rear wheels/tyres, the KR250 used a fat 16 incher at the front with a rear 18 inch.

The rid­ing po­si­tion was de­scribed by testers as “tightly con­fined”, and other less flat­ter­ing words, par­tially due to the deeply sculp­tured seat which worked well on the track but al­lowed lit­tle room for move­ment out on the road. The over­all rid­ing po­si­tion al­lowed a more up­right seat­ing than its ri­vals, an­other ben­e­fit for off-race­track use. The 16 inch front wheel and the rake/trail com­bi­na­tion could make for frisky han­dling, es­pe­cially on rough roads, and the rear brake was of­ten crit­i­cised for lack of feel, lead­ing to lock ups on oc­ca­sions.

Track at­tack

Clearly, the KR250 was directly aimed at the intensely com­pet­i­tive 250cc Pro­duc­tion rac­ing class, which was pop­u­lated by some of the most promis­ing emerg­ing names in the sport, as well as a few vet­er­ans. Sup­plies of the new model be­gan ar­riv­ing in Aus­tralia by mid-1984 and the lit­tle green ma­chine (en­tered by Team Kawasaki Aus­tralia) (which was also avail­able in red) made its Pro­duc­tion Rac­ing de­but at Calder Race­way on July 1st. In the hands of Rob Phillis and Scott Stephens, both more ac­cus­tomed to Un­lim­ited class ma­chin­ery, the new­comer sim­ply de­stroyed the op­po­si­tion, run­ning 1-2 un­til Stephens crashed around half dis­tance. Phillis also claimed a new class lap record. TKA team boss Neville Doyle said the

bikes had been un­touched from the crate other than chang­ing lu­bri­cants, and Phillis praised the ‘low­down grunt com­pared to the other bikes (Suzuki and Yamaha), and I reckon they are quicker in the top end too.” Stephens added that the KR250 was bet­ter un­der brakes as well. Doyle said, “It’s got fairly us­able power from 6,000 rpm and it goes right through to 10,500. There are no sud­den jumps in the power­band or any­thing like that. It makes it more ride­able than the other 250s.” There was so much mut­ter­ing among the van­quished that of­fi­cials im­pounded the top ten fin­ish­ers at Calder for a manda­tory strip-down to check all was as it should be. The re­sult was that the two KRs passed with clean sheets, while four of the op­po­si­tion did not. Slightly miffed, Doyle said that the KR250 had proved its point and that TKA had no fur­ther plans to en­ter the 250s in Pro­duc­tion races. Among the op­po­si­tion, sev­eral were al­ready on their way to the lo­cal Kawasaki dealer to place an or­der.

For the next two sea­sons, the KR250 held its own in the class, no­tably in the hands of for­mer Suzuki rider Ian ‘Buster’ Saun­ders, who scored many wins. Prob­a­bly the high­est pro­file event for the class was the an­nual Bathurst meet­ing, but in 1985 Saun­ders could only make it to third af­ter a bad start be­fore the KR250 went onto one cylin­der in a race dom­i­nated by RZ250 Yama­has, and where the first ten fin­ish­ers all sub­stan­tially bet­tered the ex­ist­ing lap record. Win­ner Rusty Howard’s RZ250 Yamaha clocked 196km/h down Con­rod Straight, com­pared to Saun­ders’ 180km/h. It was the same story in 1986, when the mar­que trio be­came a quar­tet with the ar­rival of the Honda NS250. Again, the lap record was pum­melled and in a five-way sprint to the line, Saun­ders’ KR250 was out-dragged and he fin­ished fifth.

That was about it for the Tan­dem Twin as far as pro­duc­tion Rac­ing went, with the new TZR250 Yama­has en­gulf­ing the class for the next two years. With the model clearly out­classed, Kawasaki went back to the draw­ing board and scrapped the Tan­dem Twin con­cept in favour of a con­ven­tional par­al­lel twin (al­though still with the KR’s 56 x 506 bore and stroke), the KR-1 and later KR-1S. Launched in 1989, the KR-1 took on, and briefly de­feated, Suzuki’s all­con­quer­ing RGV250, which it­self launched the ca­reers of so many top rac­ers, in­clud­ing Mat Mladin and Troy Corser. In its ul­ti­mate form, the KR-1S was good for 55 bhp, but pro­duc­tion ended in 1992.

To­day, the orig­i­nal KR250 is a very col­lectable mo­tor­cy­cle, pro­vided you can find one that has not been rid­den to de­struc­tion. With its con­fined (cramped?) rid­ing po­si­tion it is not a ma­chine for the larger rider, but the torque and wide power­band make it a more for­giv­ing pack­age for ev­ery­day rid­ing than its tra­di­tional ri­vals.

Gregg Hansford on the TKA KR250 at Ade­laide Race­way in 1980.

ABOVE Right side with Mikuni flat slide carbs. BE­LOW Left side with wa­ter pump and damp­ing ad­just­ment knob pok­ing out of the belly pan.

KR250s to the fore: Ian Saun­ders leads Trevor Man­ley (105) up the mountain on the open­ing lap of the Bathurst 250cc Pro­duc­tion Race in 1986.

Ian Saun­ders at Oran Park in 1986. John Richards (69) leads Ian Saun­ders (98) and Rodney Browne – all on KR250s – at The Cut­ting in the 1986 Bathurst race.

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