THE CLASSIC, COMPLEX CR93 · d · racer Analysis and track test of Honda's 125 dohc twin pro ucuon THE Honda CR93 125 c.c. Produ ction Ra ce r wa s perhap s th e ni ces t rac er ev er offered for sale to th e publi c. 1Vter n ea rly a de ca d e th e droning dohc twin s still make the leaderboard a t th e TT, yet never figure w ell in th e spee d trap hi e rar chy. The 125 twin i s of classic de sign with gear-driven doubl e-overh ead ca m shaft s and four valv es in ea ch cylin- der. The whol e machine is of such a small size th at th e overworked metaphor of "wa tch lik e" pr ec is ion is ju stified. Thoug h outclassed by th e two -strok es n ow , the l on g lon g ra ces on the I sle of Man still allow th e magnifi ce nt r eliability of thi s cla ss ic motor to win thr ough. A small bat ch of CR93 s was produ ced with full r oa d e quipm ent , and th ese few ma chin es are n ow to be found in th e · private co ll ec tion s of rich and enthu si- astic Americans. There are a few ma chine s that m erit th e descripti on " cla ssi c" eve n though th ey ar e still active on th e tra ck s t oda y . The li st is short but th e entrie s ar e familiar. The Manx No rton s, the Match l ess G50 and AJ S 7R , the MZ 204, th e Honda CR9 3 head thi s li st and w e intend to o bt a in tra ck impr ession s of eac h and all of th em , treatin g them as modern ra cin g ma chin es -16 374 Mo torcycl e .Sport ,. Octol}er 1972 and makin g no allowan ces for th eir eld erly design and con stru cti on. One severe problem is that of loca tin g such ma chine s in original conditi on. l have been looking for a Vin cent Shadow in original spe ci fica tion and goo d eno u g h cond ition to rid e fairl y qui ckl y for severa l years-wi th a compl ete l uck of success . All th e " original " m achin es th at on e lo ca tes swiftly di splay feet of cla y as one modifi ca tion after another emerge s und er th e str ess of verbal examinatio n. Mu ch the same situation exists for these old rac in g machin es, and th e numb er of original- spe cificati on bik es is severely limited. The first of th ese ma chin es to beco me avai lab le was th e Honda CR93 owned b.y Tom Lou ghrid ge. The offer to tr y it aro se at a chan ce mee ting at th e Spon don Enginerin g stand at th e Show at th e Ho.r- ti cultural Hall s earlier thi s yea r. Late 111 A pril we met at Silverstone durin g a So uthern Sixty Seven Racing Club prac- tice day , and a fair fleet of two -stro ~es pour ed out of Tom ' s van , to gether with the lit1l e Honda . Althou gh it is a 125, the machin e as a whol e is fairl y b ig. It is certainl y heavy for a 125, and is lon g enou gh for men as lar j:!e as Tom and ''.ty~clf lo fit on Lo it in c:omf orl. Co mfort b no luxur y on a long nwe. T he 111 cr cs 1 ar h e in an ankl e or wri st ..an be1"om c cripplin g aft er th e first h our or so. Th e hi :.d1 , w_ id c anti hand some riding posit ion naturally mean~ that the CR93 is hardl y th e small e, 1 of 125s. In fal"t it mu st b e one of th e bi gges t, and certainl y there can l,c few heavier ! A dry weight if 128k g (3 101b to th e unm c lric ated ) is suh stunliall y in ex ,·c,, of th at of a TD2 250 Ya maha. Whereas the Yamaha ha· 250 c.c. and about .i .1 l,.h .p . a l 10,000 r.p.m ., th e " Jilli e" Hon<la hns around 10 .5 b.h .p. at 11,500 ( a figur e th a t C see in th e manual and hcg leave lo do ubt after riding th e m:whin e , as e\"en th e H onda UK data shee t refer s Lo gearin g for 13,500). ·aturall y th e Honda is no ball of fire in acce leratio n : how e\"er. thi s do es not m ean that th e top speed is low. Af ter a long run -in ove r 100 111.p.h. is availabl e, and ce rt ainl y it mu , t be easier lo maint a in suc h a l on μ:-lcμ:ged pa ce on th e I sl e of Man clue to th e sm oo th pow er deliv ery and reasonable pow e r band. T hi s is very mu ch Tom Lo u;.:hrid ge· 5 cx - perien,· c : neve r d oe s hi s CR93 show up in th e first f cw ( or even th e fir; t 10} 125 c .c . s p ee d t rap fig ur e ,;, but n eve r t h e- less h e ge ts on to th e lcad c rhoard within a lap. The oth e r v irtu es r eq uir e d of a heavy 125 are good brak es and goo d handlin g. The Honda 1·e rt ;1inly ha s th e br a ke s- whi c h work ex tr c m e h- well- but tJ1e handlin g und e r 1, le of Man ,·o nditi ons is not so goo d. A t S ilv er s to n e . h oweve r. th e C R 93 handl e s well and aho stee rs beautifull y. Th e sm oo th s urf:u· e of the airfi e ld c ir c uit do c s n o t r e all y provoke trange ant ics, and th e s h ee r w e ight of the m ac hin e te nd s to h e lp a bit in th e i land. Th e n ee d to pr e;,,; 0 11 a h it plu s the lol\I r oad s is th e co mbinati on th at pr ovo ke s c o mpl ain t. W h e n c on s id e ring lonμ:. 10 11μ: ra.- es s u, ·h as the ; c, th e s h ee r reliability of th e H o nd a is a c on s id e rable a ss e t. La s t ye ar thi s wa s p r oved to be tru e, but sin ce thi s articl e wa s fir s t draf ted Tom Loughridge has run in th e 1972 TT wh e r e h e wa s for, -ed to r e tir e af te r abou t a lap wit h en gin e. po ss ibl y cra nk sh aft troub les. T h e o ri g in s of th e C R93 w e r e in th e flee t C B92 road ma chi ne. Thi s shar ply styled liul e 125 wa s prov e d to be capabl e of over 80 m.p .h . on th e road a decade ago. It i s worth rcmemhe1·inμ: that , wh en ful some pra ise is b e in g b e;.t owe d o n 80 rn.p.h . 125s of tod uy : th at old Honrla r ea ll y h a<l s peed. Th e C B9 2 wa s- and still is- th e ba s i s for qui te a few ra cin g 125s, p ri va t el y co nv e rt e d b y u s in g Honda Race Kit s. Con trar y to pr ese nt day po li- cies. once u po n a tim e in th e Golclcn Day s Hond a (U K) used lo bring in Ra ce Kit s. Sadly the se day s are lon g past, and you ca n b eg in va in for eve n a knobbl y rnm sh aft for your Produ ction Ra cer these day s . . . unl ess yo u go to Fr ance : or Sweden : or USA: or Singap ore : or . • . . Th e CR93 was never a converted road m ac h ine. It wa s, ind ee d, ba sed on th e C B9 2, but ra c in g developm ent was ca rri ed out by Honda (Japan ) an d a sur- pri sin g nu mber of CR93 s wer e produ ced- eve n a few in full road trim, with li ght s, stands and other road legal fitments. T he bar e tec hni cal detail s of the CR93 are ns foll ows : le n gth, 2 m etre s ; width, 0.6 metres; height , 0.9 metres; wheelba se, 1. 3 metre s ; ground cl ea ran ce, 0.15 metres; dry weight 128kg, bor e 43mm, strok e -l3m111 , di spla cement 124.8 c.c.; comp ression ratio, 10.2: 1; carburettor s K e ihin RO:,!\I, 22P6; fuel capacit y, 10) litr es ; oil ~,imp, 1.1 litr es ; clut ch, dry multipl ate ; tr an smi ssion , five gears : 1st, 1 : 2; 2nd, 1429; 3rd 1 : 227; 4th I : 083; 5th 1: 01 tyre s-2.5 0 x 18in front , 2.75 x 18; igniti on-e n ergy tran sfer. T h e pr e paration s for running the CR9 3 are spelt out with great cure in a data ;.h ee l p r epar ed by Alf Brigg s nt Honda (UK). Alf hu s for many years kept tJ1e C R9 3 and CH.llO rac ers on th e tra ck by hi s valiant effort s in obtaining and issuin g spar es from a sto ck th at is kep t with (but not of) , the rest of Hond a's central stork s in the UK. T hi s servi ce is not ju st extended to tho se rid ers in the UK : hi s customers are worldwid e . Surpri singly, after so many years there are still enoug h genuin e spar es to ke ep several CR3 s run- nin g, and running weJI . Honda did in- de ed produ ce one of their excell ent spar es li sts for the machin e, and with typica l thoroughne ss even megaphone caps and ma chine stand s have th eir . own i llu stra- tion and part numbers. The dat a sheet tak es up wher e th e fa ctor y left off, and embodi es mu ch of the experience gained by rid ers runnin g CR9 3s in th e UK. Remember Rod Scyvie r's Briti sh Cham- pion ship on a CR93? Warmin g up tl1e CR93 i s don e on soft plu gs and is a fairl y slo w proce ss : th e howl from the megaphone i s a delightful change from tl.1e two- strok e, and s.ee. ms po sitively mellow af ter the head-sphtt~ng screa m of ma ssed two -stroke s, to wi n ch we lrnve b ec ome painfull y acc u stomed in re cent years. (Sure ly ,some cleve r engi- neer could find a way of ge ttin g all that wasted ener"y into th e en gin e and onto " . . ?) the back whe el-and giv e qui et aga m. On ce th e en"ine i s warmed, th e oil i s " · NG K chan ged and hard plu gs put m. C9H (warm ) and 13/ 14H (hot ) u sed to be suggested. In addition to thi s pro cess , it is recommend ed that th e oil be war~ ed befor e starting the ma chin e up .. Like mo st Hond as , th e CR93 ha s a ce ntrifu gal oil filter and thi s mu st b e cl ea n ed out each .tim e the oil is ch ange d . Th e. R20 . grade is u sual , wiili R 30 for hott er limes. FRONT BRAKE ASSEMBLY 12 IGNITION lb 13 ~--@ ' IZ 13 12 ®--@ ,~ ' 12 IJllP1 IZ 13 Motorcycle Sport , October 1972 375