Practical Sportsbikes (UK) - - Contents -

The RCM Sanc­tu­ary A16R, the Z1000 for the new age. And boy, is it some­thing to be­hold

Rad­i­cal Con­struc­tion Man­u­fac­ture USA (RCM USA) has started to pro­duce ul­tra-trick spe­cials based around Kawasaki’s KZ1000 (Z Thou to us) un­der li­cense fro­mac Sanc­tu­ary in Ja­pan.the bikes, co­de­named A16 and avail­able in three base forms (A16R-RCM001, a ZI-R in­spired street racer; A16R-RCM004, a naked black and gold caff-ish racer with drop ’bars; and A16S-RCM007, a red higher ’barred road­ster with usd forks).

The heart of all three is a scratch-built 1045cc Zed mo­tor, breath­ing through an elec­tronic fuel injection sys­tem (es­sen­tial in or­der to meet Cal­i­for­nia’s strin­gent emis­sions laws) and a ti­ta­nium four-into-one sys­tem fit­ted with a sec­ondary air-injection sys­tem at the man­i­fold, again to help the ’70s mo­tor at­tain emis­sions regs.

As well as be­ing built from the cases up, RCM claim to ad­dress a num­ber of in­her­ent weak­nesses with the mo­tor, re­plac­ing a num­ber of com­po­nents with up­grades, al­though they re­main coy about ex­actly which parts.the stock mo­tor’s bot­tom end is bombproof so we sus­pect the up­grades to in­clude stronger valve springs and a man­ual cam­chain ten­sioner. Claimed power is 99bhp at 8000rpm and 66.5lb.ft at 6500rpm, com­pared to 83bhp and 55.8lb. ft of the stock Kz.that’s a healthy hike without mak­ing the mo­tor into a peaky rev-mon­ster.

The big­gest change over the stock Kawasaki is the Sanc­tu­ary-en­gi­neered frame. Built from scratch from high-ten­sile tubu­lar steel, and tested ex­ten­sively in rac­ing in Ja­pan, the A16’s chas­sis keeps the orig­i­nal’s style while in­cor­po­rat­ing many mod­ern twists.the head­stock, for ex­am­ple, is not only fat­ter and much stronger than that of an orig­i­nal Kwak it’s also set 25mm fur­ther back and 30mm lower, re­duc­ing the bike’s wheel­base by 18mm.

More changes ap­pear at the rear.the sub­frame is all new, as well as shorter.the top shock mounts are po­si­tioned sev­eral inches for­ward of where Kawasaki fit­ted the KZ’S. Com­ple­ment­ing this change is a swingarm pivot (20mm in di­am­e­ter to match mod­ern prac­tice) 10mm lower than on a KZ.THE swingarm it­self is an achingly beau­ti­ful, un­der-braced Sculp­ture item fash­ioned from box-sec­tion alu­minium. Shocks are fully ad­justable Öh­lins pig­gy­backs. Both R mod­els run rwu Öh­lins teles; the S wears usd forks, again Öh­lins.

We could swim for days in the de­tails alone. No ex­pense or pure en­gi­neer­ing so­lu­tion has been spared in build­ing these frankly porno­graphic ma­ won’t get change from £30K for one of these ei­ther. But as good as they look, they’re for rid­ing too, so PS sent Ja­panese test rider Ryuji Tomono along to RCM to try the A16 for him­self. Need­less to say, he wasn’t dis­ap­pointed.


The Kawasaki KZ, suc­ces­sor to the leg­endary Z1, has been loved, cus­tom­ized and up­graded by cus­tom-builders from around the world for the last 40 years. Cur­rent trends favour these clas­sic su­per­bikes on wide 17-inch wheels, to max­imise sticky tyre choice. But this isn’t without its prob­lems.this ex­tra grip and change in wheel pro­file can cause in­sta­bil­ity on these older chas­sis. Ja­pan’s AC Sanc­tu­ary and now Cal­i­for­nia’s RCM say they have the an­swer for this blend of clas­sic style and mod­ern en­gi­neer­ing. The A16.

The essence of this ma­chine is per­for­mance, pure and sim­ple, and RCM’S goal when build­ing the A16 was to max­imise the syn­ergy be­tween old and new. The mo­ment I swung a leg over the A16’s seat and put my hands on the clip-on ’bars, I felt it fit­ted me per­­ding clip-ons to this type of clas­sic su­per­bike can make the rider lean an un­com­fort­ably long way for­ward, al­most crouch­ing over the fuel tank just to reach the con­trols. But the A16 is dif­fer­ent. RCM al­ter the head stock (which is fat­ter and stronger than stock) and po­si­tion it to sit 25mm fur­ther back and 30mm lower than on the Kawasaki Z1000 chas­sis. So de­spite racey ’bars the rid­ing po­si­tion is com­fort­able and nat­u­ral yet pur­pose­ful, even for smaller rid­ers.

RCM’S frame di­men­sion tweaks don’t end there.thea16’s swingarm pivot is po­si­tioned 10mm lower than that of the Z.along with strate­gi­cally placed brac­ing,

these chas­sis changes make for a much stiffer frame than the orig­i­nal Kawasaki item. Not only that, the cen­tre of grav­ity is lower, giv­ing the bike a more cen­tral­ized mass again im­prov­ing con­trol and feel for the rider. Han­dling is fur­ther aided by a sub­stan­tial re­duc­tion in weight – the A16 is a full 44 ki­los lighter than a Z1000.

When I turn on the ig­ni­tion and push the starter but­ton, the en­gine wakes up from a sleep as fuel mix­ture sprays through the in­lets into the com­bus­tion cham­ber from the elec­tronic fuel injection sys­tem (it­self a re­sponse to Cal­i­for­nia’s strin­gent emis­sions leg­is­la­tion).the raw bark from the air­cooled two-valve unit pops with nostal­gia, yet the crisp and in­stant throt­tle re­sponse gives the unit an edge of moder­nity. It’s an in­tox­i­cat­ing blend of old and new, es­pe­cially for those who have fond mem­o­ries of these Kawasaki pow­er­plants from back in the day.

Once on the move the fully re­built en­gine re­sponds well. RCM haven’t gone for huge power, rather us­abil­ity.with 99bhp and 66lb-ft of torque to hand there’s more than enough per­for­mance to draw from. But un­like mod­ern en­gines the A16 re­tains its old school vibe and charm and, in do­ing so, re­minds me of my ado­les­cent en­thu­si­asm for these bikes. Rad­i­cal tun­ing can spoil the char­ac­ter of these 1970s dohc mo­tors, es­pe­cially for the road. Re­tain­ing the rich seam of torque is es­sen­tial for that all im­por­tant drive out of bends.

Al­though the sen­sa­tions and clas­sic feel are there with the mo­tor – it’s still got a big, heavy crank so it pro­duces power like a build­ing wave rather than the spin­ning tur­bine ef­fect of a mod­ern en­gine – the han­dling and road man­ners of the A16 are far more up to date. I don’t have to plan well ahead just to get the thing around a cor­ner.

Our test route took us through some very chal­leng­ing, wind­ing roads, where a proper clas­sic Z1000 would be a real hand­ful.these old timers with their skinny tyres, ba­sic sus­pen­sion, lim­ited brak­ing per­for­mance and heavy mass re­quire big in­puts from the rider and de­lib­er­ately smooth arc­ing sweeps through the turns to give their best. Aboard the A16 how­ever, I felt as if the bike was guid­ing me. On a Zed you need to pull the bike through the cor­ner and lean with it to hold your cho­sen line – they’re a very phys­i­cal ride.thea16 re­moves that ef­fort and re­sponds equally well to a clas­sic style or a more aggressive su­pers­port type in­put. The chas­sis re­mained planted and con­tin­ued to re­lay feed­back even when I dragged the front brake into and through a cor­ner – not some­thing I would try to at­tempt on a pe­riod Zed.

I never dreamed an air-cooled four-pot


en­gine held by a steel tubu­lar frame would per­form like this. I in­creased the speed, but the A16 never dis­ap­pointed or lost con­trol. All of my in­puts were re­warded with ac­cu­rate and pre­dictable re­sults. It turned so cleanly and ac­cu­rately largely be­cause of that al­tered steer­ing an­gle. By com­par­i­son a nor­mal Z falls into a turn, then strug­gles to pull it­self through and out the other side be­cause of the high-cen­tre of grav­ity and high roll-axis.the changes RCM make to

the A16 frame com­pletely trans­form the han­dling char­ac­ter­is­tics, and move the ride on by sev­eral decades.

The real test for this RCM frame is its abil­ity to al­low the bike’s high-grade com­po­nen­try to shine. Parts like the sta­teof-the-art Öh­lins forks, ra­dial-mounted Brembo calipers, and light­weight OZ Rac­ing alu­minium forged wheels would eas­ily over­whelm a stan­dard Z frame, caus­ing it to re­spond and han­dle per­haps even less ac­cu­rately than with orig­i­nal parts.thea16 runs nim­bly through wind­ing roads al­most as if it’s danc­ing.

As you’d imag­ine the sus­pen­sion gives a plush, com­posed and com­pli­ant ride, and rider feed­back is as good as on a top level su­per­sports ma­chine. Steer­ing and turn-in are light and re­spon­sive thanks to the OZ wheels, and brak­ing is ex­actly as strong as you’d ex­pect from a ra­dial Brembo set up. Two dig­its are all that’ll ever be re­quired on the lever.

Once on 17-inch wheels a bike with a strong, taut frame, like the A16’s, will ac­cept a mod­ern rid­ing style. But even so, when cor­ner­ing af­ter brak­ing hard, it’s not un­com­mon to ex­pe­ri­ence un­der­steer as the stresses put through the frame and steer­ing stem from sticky rub­ber and com­pli­ant sus­pen­sion can of­ten over­whelm even an up­dated and im­proved chas­sis. Sur­pris­ingly, how­ever, the A16 is free from any such an­tics.the steer­ing is not that far off that of a mod­ern su­per­sports ma­chine. Com­bine that with the feel and force of the big twovalve mo­tor and the A16 is a real joy to ride.and to ride fast.


A Ja­panese race school in­struc­tor, and free­lance writer for elec­tronic and print mag­a­zines.

Lov­ing that snakey ex­haust mount­ing bracket (and the rest)

Top: En­gine ar­chi­tec­ture that has truly stood the test of time. If it ain’t broke... Above: Com­puter de­sign shows the RCM’S stumpier wheel­base com­pared to stock KZ

Fuel injection re­places carbs. Looks OK though

They didn’t hold back on the candy in the paint

Yes, it’s bloody lovely

Ea­ger to turn where an old school Zed would protest

Push hard on a tra­di­tional Zed and you’ll know about it. The A16 just gets on with things

Tomono (cen­tre) with some of the RCM crew

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