Em­pire Twin E120S

Old Bike Australasia - - CONTENTS -

One for the road

Just when you think you’ve com­pleted the story of the range of v-twins built en­tirely in-house by Doug Fraser in Mel­bourne, along comes a new chap­ter. Doug calls his creations Em­pire Twins, af­ter BSA’s pre-war Em­pire Star sin­gles from which the con­cept sprang.

For a brief up­date on this evolv­ing saga, let’s hark back to Chap­ter One, which ap­peared in OBA is­sue 10 – eleven years ago! Doug says this sem­i­nal ma­chine in the Em­pire Twin story is the mo­tor­cy­cle that BSA de­signer Val Page would have built had he been given a free hand. In­stead, shack­led by man­age­ment pol­icy, BSA’s v-twin was the Y13, a mo­tor­cy­cle that has never overly thrilled Doug Fraser. So he made his own.

The 2008 Em­pire Twin M46 (two x M23) dis­places 1120cc, with a bore and stroke of 87 x 94mm and a 9.0:1 com­pres­sion ra­tio. There were M20 parts in­cor­po­rated, in­clud­ing the “stretched” frame, but ba­si­cally it is all Doug’s work, and there are no CNC ma­chines in the EMU Engineerin­g work­shop, which is his core busi­ness, man­u­fac­tur­ing elec­tri­cal com­po­nents. 1400 hours later, it was a run­ner, com­pleted just in time for the All Bri­tish Rally at Castle­maine, Vic­to­ria, where it stole the show and won “Best Bike of the Rally”.

Dur­ing con­struc­tion of the Em­pire Twin, Doug com­pleted a sec­ond set of crankcases, and Chap­ter Two ap­peared in the form of the B66 (two x B33) which was com­pleted in 2010 and fea­tured in OBA is­sue 20. This is es­sen­tially a pair of highly mod­i­fied BSA B33 top ends on Doug’s crankcases, al­though he made the top ends too. In­side the cases sit a pair of M20 drive-side fly­wheels, joined by a Har­ley-David­son crankpin on a four roller bear­ing crank. With a bore of 88mm and a 94mm stroke, 1140cc was the re­sult, with a 9.25:1 com­pres­sion ra­tio. Mounted in what could be, but isn’t, a Gold Star rolling chas­sis, the re­sult is a su­perbly styled mo­tor­cy­cle, that, had it been built in Small Heath in 1955

in­stead of Mel­bourne 55 years later, may well have saved Bri­tain’s largest mo­tor­cy­cle com­pany.

This could have been the end of the Em­pire Twin story, but oh no, not yet. With two big road burn­ers com­pleted and be­ing well used, Doug turned his at­ten­tion to a track-only ver­sion, be­cause he has al­ways been a keen and highly tal­ented racer. His most re­cent track weapon was a self-built and de­vel­oped (what else?) Nor­ton Ro­tary which he has raced with con­sid­er­able verve in Aus­tralia and New Zealand. But in his words, the Nor­ton was pretty much worn out, so it was time to get out the draw­ing board once again. Hav­ing cre­ated a line of the V-twins BSA should have built, he now wanted one that in­cor­po­rated some re­ally orig­i­nal think­ing – and the ques­tion, “What would BSA have built if they were still in busi­ness in 2012?” sprang to mind. That be­came E120R (R for Rac­ing), which broke cover in late 2011, and which I was able to sam­ple at Easter 2012 at the Broad­ford Bo­nanza. My im­pres­sions were pub­lished in OBA 34, but suf­fice to say, it was quite an ex­pe­ri­ence. An eye-wa­ter­ing, adren­a­line-pump­ing ex­pe­ri­ence!

So here we are, seven years later, and num­ber four in the se­ries has just bro­ken cover – E120S (S for Sports). This is very much from the E120R mould, and yet, com­pletely dif­fer­ent. The sin­gu­lar rea­son for this fact is that the E120S has been care­fully planned from the out­set to be a fully com­pli­ant mo­tor­cy­cle, not a Red Plate spe­cial. Com­ply­ing with Aus­tralian De­sign Rules (ADR) is a mas­sive un­der­tak­ing in it­self, and it is only due to the ex­is­tence of what is termed In­di­vid­ual Ve­hi­cle Com­pli­ance (IVC) that Doug was able to do it. IVC al­lows an in­di­vid­ual per­son to make one ve­hi­cle per year for his (or her) own use, which suited Doug per­fectly. He gave him­self 18 months to have the new ma­chine ready for the 2018 BSA In­ter­na­tional Rally at Halls Gap, Vic­to­ria last Novem­ber, and he made it, just. “I had two rea­sons for choos­ing that event,” says Doug. “Firstly the In­ter­na­tional Rally only comes to Aus­tralia in­fre­quently, so it was a

great op­por­tu­nity to make a bit of a splash, and se­condly, I wanted to beat BSA’s new own­ers, Mahin­dra, to the punch!”

While the midnight oil was be­ing burned in the work­shop, there was an equally in­tense op­er­a­tion go­ing on be­tween Emu Engineerin­g and Vic Roads. Doug takes up the story. “The first aim is to get a 17-digit VIN, is­sued by Vic Roads. You start off by be­ing is­sued a Vic Roads en­gine num­ber, which en­abled me to get a test­ing per­mit, which I the­o­ret­i­cally needed to get an ADR, which I needed to be able to take it to the BSA Rally. I ac­tu­ally ran it on a per­mit there, but two weeks later I was able to fully reg­is­ter it – as BSA 12 – the plate for which I now own. I fig­ured af­ter what I’d spent to build it, what’s a few hun­dred dol­lars more? The ADR was ex­pen­sive and tricky but it had to meet light­ing reg­u­la­tions, brak­ing sys­tems, and most of all, noise. I had to prove I made the frame, and that has to be fully doc­u­mented, so I had an en­gi­neer do an in­spec­tion on the frame when it was in the roughed out stage. They are not so con­cerned with the en­gine but the frame has to be built by you, to stop re-birthing I sus­pect. The en­gi­neer could see that be­cause I had built the other bikes I vaguely knew what I was do­ing, so I had no prob­lems there. For IVC ADR there are no emis­sion re­quire­ments, so there is no cat­alytic con­verter in the ex­haust sys­tem, which is how I get away with carbs (38mm Mk2 Con­centrics) in­stead of fuel in­jec­tion, and it doesn’t have to have ABS. The ex­hausts do have Lambda probes, which is the only way I could prop­erly tune it. The ex­haust mea­sures 94 db at 3,000 rpm, with the noise me­ter 500mm from the ex­haust pipe, set at 45 de­grees.”

Al­though the E120S is closely based on the E120R, there are many de­tail changes, which Doug ex­plains. “To ad­dress the noise is­sue, I de­cided to re­duce the size of the fins on the heads and bar­rels, and that meant mak­ing new pat­terns. It runs a milder cam and with the ADR ex­haust and a spe­cial in­duc­tion sys­tem the noise level is now ac­cept­able. As with the race bike, I use Porsche in­ter­nals, all pro­pri­etary parts, Mahle pis­tons and sleeves, Pankel ti­ta­nium rods, valves, INA in­verted hy­draulic buck­ets so there is no tap­pet ad­just­ment. Without build­ing the race bike first I would never had got this one on the road – the race bike was a mule to de­velop the road bike. For the belt drive for in­stance, I found (with help from the belt sup­plier Gates) that the teeth of the belt don’t fit snugly in the pul­ley so I had to ma­chine my own pul­lies with an in­ter­fer­ence fit – you now have to stretch the belt onto it”. Like many of the pro­pri­etary com­po­nents, the gear­box came from a Honda VTR, or more specif­i­cally, a Honda Valadero, which is the dual-sport ver­sion. “With such a torquey en­gine, I wanted to use a fivespeed gear­box,” says Doug. “The VTR 1000 Honda has a six speeder, but the Va­radero has ba­si­cally the same gear­box ex­cept that it is five speed, so that’s what I used, along with a Fire­blade clutch.”

“For the IVC you can use a brak­ing sys­tem from a mo­tor­cy­cle of equiv­a­lent weight and per­for­mance. I looked at the VTR Showa forks which looked right to me, they’re rel­a­tively easy to mod­ify to fit a con­ven­tional mud­guard, and I could use the stan­dard VTR brakes. The VTR runs clip-ons but

I was able to find a yoke that I could use with con­ven­tional han­dle­bars. The VTR rear brake caliper and disc ac­tu­ally fit­ted the spoked Tri­umph rear wheel I had, which is from a 2006 Bon­neville. I needed a wheel with a cush drive and good spoke an­gle to han­dle the torque of the en­gine. Al­though the sprocket and disc were on the other side, ev­ery­thing worked quite well once it was swapped around. But at the front end I needed a spoked wheel, and to find one that had the right spoke an­gle and that would fit be­tween the rel­a­tively nar­row forks was dif­fi­cult, so I made the hub and spoked a Takasago rim, same as the rear, which

was cross drilled with a spe­cial lace pat­tern to in­crease spoke an­gle to pro­duce a rigid wheel. I used high ten­sile steel spokes, not stain­less, be­cause stain­less doesn’t have the ten­sile strength. The only other has­sle I had was to mount a drive to the ana­logue speedo. The in­stru­ments are from a Hes­keth. I have one of these mo­tor­cy­cles and have ac­cu­mu­lated a stock of parts over the years, in­clud­ing these in­stru­ments. Mod­ern bikes don’t have me­chan­i­cal speedo drives, but I was able to find a drive that had the same ra­tio as the Hes­keth speedo and mount it into the hub I’d de­signed.

“The frame is to­tally dif­fer­ent from the race bike; it is 75mm longer to give a wheel­base of 1500mm. The race bike has an al­loy swing­ing arm from a Honda CB600RR, but the road bike uses twin shocks so I used an­other of these arms which are in­ter­nally braced, but I had to cut it and weld it so it prob­a­bly would have been eas­ier to make one from scratch. I should men­tion here that all this stuff came from Vic­to­rian Mo­tor­cy­cle Wreck­ers. I used to work there years ago and even though it now has dif­fer­ent man­age­ment I get on re­ally well with them – I couldn’t have done this without them. They just let me take var­i­ous bits un­til I work out what I need, then I bring back what I don’t want. Take the start­ing sys­tem. I de­signed the crankcases to take the VTR starter, but that en­gine doesn’t use any form of de­com­pres­sion. The Honda is 1000cc on 9.0:1 com­pres­sion, whereas the E120S is 1200cc on 11.5:1, and it just wouldn’t work. So I had to pull the motor apart and fit Scream­ing Eagle Har­ley– David­son de­com­pres­sors, but the com­pres­sion is too high and they pop off too quickly, so it was back to Vic Wreck­ers to see what they had in the same di­am­e­ter and length. I ended up with one that is half Honda, half Yamaha, all Mit­suba com­po­nents, and it now works well and doesn’t need de­com­pressers. With a good strong bat­tery you just hit the but­ton and off you go.”

Prior to let­ting me loose around the back roads of Phillip Is­land, Doug gave me a run­down on what to ex­pect, per­for­mance wise. “I find on the open road you get to about 130 km/h and open the throt­tle, and it just launches, de­spite all the gear I had to fit to meet ADR. The big­gest prob­lem is the restrictio­n from the air cleaner and the ex­haust, it just stops breath­ing. It has a slow ac­tion throt­tle and when you ac­cel­er­ate you hear the in­duc­tion roar. It will hap­pily rev to 7,000 or be­yond but it hits 6,000 and it ceases to in­crease power be­cause it can’t breathe. It makes 76 bhp at 6,000 rpm at the rear wheel and has over 90Nm of torque from 3,000, which for a road bike is fan­tas­tic. It doesn’t mat­ter what gear you’re in, you just hit it and away it goes. I am very happy with the rigid­ity of the frame, it is great in the twisties. The 1500mm wheel­base is rel­a­tively long for a semis­ports mo­tor­cy­cle. I had to cut away the front of the tank to in­crease turn­ing ma­noeu­vra­bil­ity – with the long wheel­base if you don’t have de­cent steer­ing lock it’s a has­sle in traf­fic.

“I made the steel tank, start­ing with a big block of wood and a ham­mer to get it into a rough shape, then ran it through an English Wheel and shrank and

stretched it in some places. It is not a stan­dard three-piece tank, it is five pieces all gas welded. The paint­work was done by Glen Olsen who spe­cialises in restor­ing E Type Jaguars – he is a world-renowned ex­pert. I rewired his bike for him so he painted the tank and side cov­ers for me. I made the seat and it is very com­fort­able. I think the er­gonomics are good; the po­si­tion­ing of han­dle­bars, seat, footrests etc seems pretty right. It has a 12 volt power socket and it is wired for heated grips. ”

So armed with a few tips, off I went, tour­ing around some of the roads that made up the orig­i­nal Phillip Is­land road cir­cuit that was used in the ‘twen­ties and ‘thir­ties. I was itch­ing to try Doug’s sug­ges­tion of ‘hit­ting it’ in top gear from 130km/h, but on the Aus­tralia Day week­end in school hol­i­days, I don’t think so. Nev­er­the­less I did give it some de­cent hand­fuls of that slow-ac­tion throt­tle, and it sure does get up and go. As he says, there’s no point in ring­ing the bells too hard, the E120S has such mas­sive re­serves of torque you just shift up un­til 5th gear and stay there. And he’s dead right about the han­dling too. Flick­ing through cor­ners is an ab­so­lute de­light, at any speed. Given the pedi­gree of the com­po­nents, it is no sur­prise that the sus­pen­sion and brakes be­have im­pec­ca­bly, as does the gear­box – and that seat is re­ally com­fort­able. In fact, there’s lit­tle, if any­thing to crit­i­cise, nor to com­pare, be­cause this re­ally is a com­pletely unique mo­tor­cy­cle.

It is also a mo­tor­cy­cle that is guar­an­teed to draw a crowd when­ever it is parked – the sub­ject of in­tense scru­tiny and much head scratch­ing. “Never saw a BSA like this,” you can hear them mutter. No, that’s dead right.

All too soon it was time to re­turn E120S to Doug, who reaf­firmed his of­fer of an­other ride, “on more suitable roads”. By that, he means roads where you just “hit it!” I’m up for it. So will there be fur­ther chap­ters in the Emu Engineerin­g/BSA/Em­pire Twin/E120 saga? Doug is non-com­mit­tal on the sub­ject but adds, al­most as an af­ter­thought, “But I am al­lowed to make one ev­ery twelve months… for my own use.” And mine, I hope!

The fam­ily prior to E120S: From left: E120R, B66, M46.

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