First look: Honda NR750
The 32-va lve, oval p iston, 749.8cc, V-4 H onda NR750 is a direct
descendant o f th e NR500 wh ich was tested by HRC from 1979
to 1982. T he 20,000 rpm redlined NR500 was ridden primarily
by T ak azurni Katayama of Japan. although Freddie Spen cer rode
it a t Laguna Seca in July of 1981 and in the British GP th e
following month. Spencer won a qual ifying heat a t Laguna Seca
but mech anical problem s prevented him from logging more th an
a handful of laps in th e two 100-kilometer legs of th e race. In
th e Belgium GP. Spen cer qualified 10th fastest and ran as high
as fifth in th e race before mech anical problem s side lined th e
NR500 once aga in. Katayama n ever did achieve a good resu lt
with th e NR500.
.
T he new fo ur-stroke. liquid-cool ed , DOHC NR750 engine
p roduces a lmost 150 horsepower, accordi ng to H onda , a n d is
mounted in a n alu minum fram e sim ila r to th e H onda R VF750
en dura nce road racer. It a lso employs th e advanced single-sided
sw ingar m (Pro-Ar m) , which was developed o n th e Wo rld
Championsh ip win ning R VF750. Dimen sions of th e I R7 50 differ
slig h tly from th ose o f th e R VF750. The NR750 is 5mm longer
an d 20mm wider with an overa ll height a nd ground clearance
which is lOmm lower.
H onda says th ey are fielding th e bike to test n ew technology
" u nder th e most extre me ra cing co nd itio ns," and to improve
co nventio nal en gine technology in th e following area s: I )
Induction/ exhaust technology. 2) Cylinder h ead/valve design. 3)
Emissions/noise contro ls.
While Honda announced that th ey would contest th e 1987
World Championship Endurance Road Race Seri es with the
NR750, th e bike fail ed to appear in th e opening round of th e
series in Spain on May 10. HRC did field th e NR750 a t th e April
19 24 H ours of LeMans, a n interna tio nal endu ra nce ro ad race
bu t n ot par t of th e World Cha mpionship Series. At L eMans th e
N R750 qualified seco nd fastest, just three-tenths of a seco nd
behind a n HRC RVF750. According to H onda, the NR750 was
runni ng fif th in th e fourth hour when "a bolt broke a nd the
resu lti ng metal fragmen t ca used a piston seizure."
