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/126804
a: ~ ~ w ~ ...J ~ ..... ;;: > al en c ..... c ::t: 0- ~ 00 ~ ..... ~ 0 ~ >- l-o ~ = c:: ~ ~ Honda 's for-sale short t rack and TT race engine is based on the XL600 and sells for $2300 complete w ith ignition system. ' The RS500D engine comes as a left-hand-shifter, but can be converted to right-hand shifting. Transmission has five speeds. RS 500D 's good power output and broad powerband is du e to hemisph erical combust ion c hamber and red iallv-posltlened va lves, say s Ro b Muzzy. Sp lit intake port works w ith a spec ially-shaped intake manifold (not shown) supplied w ith each eng in e. Note ang les of valve guide holes. Headed for Houston: ,efficient com bus tio n chamber he's ever worked on. Alo ng with th e engine, Honda delivers a lis t o f sour ces for pa rts lik e the frame, whee ls, forks, shock, etc. needed to prod uce a com plete racebike. Honda's RS500D dirttrack enqines By John Ulrich T h e idea, says T eam Honda dirt track m anage r G en e R omero w h en talking abo u t th e 40 for-sa le Honda RS500D engines, is that a guy can buy one en gin e and one fra m e a n d ru n both TT a nd short track races with o ne motorcycle. TT 11 600 csingles: short even ts a ow c . . ' tracks have a 500cc limit, So the 16 RS500D en gi ne comes with a 600cc co nve rsio n kit included in its $2300 price. • •• • , - ~ .. _ .a - .. - To date, 32 of th e 40 engi nes ha ve bee~ sold: All are ba sed o n t~e XL6~0 engme WIth fou r valves ra.dla lly ~IS- p la ced aro u n d the hem ispher ical co mb ustion cha m ber. H on da calls it Rad ial Four Va lve Co m bus tio n (cham ber) a nd team engi ne bu ilder Rob Mu zzy says it 's the neatest, most- of • • " "~ ""'''''~ . "''- _ - . . -. . " , ~ '\""' .. Co mpared to the XL600 eng ine o n whic h it is based , the RS500D eng ine has a d ifferent cylinder head with more fin s and modified ports, an ART-forged racing pi ston, a ba lancer sha ft with a soli d gea r (vs, the XL's spri ng-loaded, spli t-gear to reduce gear noise), a non -racheting cam chain ten sioner, a n oil pump with a lar ger scavenge side an d a restricto r on th e feed side, a mac hi ne d- fro m -bille t cl utch h ub a nd center a nd associa ted parts sized to acce p t an extra fric tio n a nd an extra steel p lat e, a heavier , flywh eel, a nd side cases,machined to accept th e larger flywheel o n one side an d th e deeper cl u tch on the o the r. The engin e is sold with ign ition ' but wi thout a ca rbure tor a nd exh a ust - - ._----_.: . system (Honda recommends a Miku ni 40m m carb and a Kerker exha ust developed fo r H onda 's 1985 dirt track raci ng pr ogra m by Steve Joh nson o f Kerk er); as delivered, it weighs 90.4 po u nds. H onda claims th at th e 498cc version of the engine prod uces 54.2 bhp @ 8250 rpm a nd 39.8 Ib.-ft. of torque a t 6000 rpm . With th e ' 600cc kit ins talled - the kit in cludes pi ston, rings , cylinder. gas kets and cams ha ft - actual di splacem ent is 589cc with 59.2 bhp @ 8000 rpm a rid 44.3 lb.-ft. @ 5000 rpm. The figures apply to engi nes fitted with th e recomme nded carbure tor a nd ex ha us t system . As fo r th e re ma in ing engi nes? T hey' re wait in g for bu yers, and inte rested parties can co ntact Keith Reeves a t Team H onda, 213/604-2545. Ever ybody else can show up at the Houston Astrodome o n Feb ruary 8-9 a nd see how H onda's R FVC RS500D engi nes fare in th e hands of Team Honda 's R icky G raham and Bu bba Shobert a nd a herd of priva teers. • .. _ _--. \ ... ... .