A btilliant rcd and blue scheme on the XR makes it look fast.Like the TT, it's got all the little enduro gear: a speedo, ,ightsand a tool bag.

Long and low, the TT makes lor a good MXer and a deluxe en-duro bike. Endurc lighting and a small odometer, with a fender-mounted tool kit, are designed fot the timekeeperc.

A slim chassis and a smooth-flowing saddle are pluses for theKfM, lt's the easiest to start of the big four-strokes.

WHAT ARE THESE BIGMACHINES USED FOR?

By and large, the big four-strokes areused as fun riding machines by older orlarger riders. A properly set-up big four-stroke can be a pure joy on a long trailride.The range of a single small gas tank is near-ly twice that of a two-stroke of the samedisplacement. Also, many riders appreciatethe smooth low+nd gunt of these monstersand spend many a pleasant hour searchingfor a hill they can't climb.

A small percentage of the four-strokeowners race their bikes, some of themagainst two-strokes in various forms ofcompetition. These are the same riders whoalso end up spending a great deal of timeand money on their machines to have MX-quality forks and shocks, and maximumhorsepower.

The majority of folks who compete withrelatively standard four-strokes do so in theincreasingly popular four-stroke classesthat can be found in many forms of racingnowadays. Just about every sanctioning en-duro organization has a four-stroke class.Many Grands Prix have a thumper class,and a special thumper class can occasion-ally be found for On-Any-Sundoy moto-cross.

8 DIRT BIKE SUMMER SHOOTOUT SPECIAU1983

Then there are those four-stroke-onlyevents that are becoming more and morepopular. The Dirt Diggers M.C., for ex-ample, draws huge numbers of riders to itsyearly Dinosaur Run, a four-stroke-onlyevent. There are also a considerable num-ber of four-stroke championships eachyear, as well as a competing pair of four-stroke Nationals.

A small percentage of four-stroke buyersare simply not satisfied with anything closeto a stock bike. These are the "specialbuilders," riders who start with a standardbike and wrap a special frame and all theattendant goodies around it. These fanaticscan expect to spend upwards of $5000 tocomplete a polished package. Liberal useof titanium, aluminum alloy, plastic,chromoly and money is essential.

HOW WE'LL RATETHESE MACHINES

The DB staff will be searching for thethings that make up a good thumper. Thatis, great low-end and mid-range power.Another important feature to consider willbe how good the suspension is, as delivered.While it's nice to bolt a set of Simons forksand an Ohlins shock onto a bike, it stillcosts a lot of money. Overall handling willbe considered, too, but the most weight inour ratings will be given to how versatilethe bike is, stone stock. If a big four-strokemakes a great trail bike, a reasonable en-

duro mount, and can perform well on aMX track, then it clearly has a whole lotgoing for it. And that's what we'll be look-ing for. But first, a brief description of thecandidates:

CAN-AM SONIC sOOMXA completely new bike for 1983, Can-

Am has abandoned the old twin-shock rearsuspension and gone to an Ohlins single-shock setup. The design and production ofthe bike is rio longer done at the Bombar-dier plant in Montreal, but is now puttogether in England at the ArmstrongMotors plant.

Its product is a Marzocchi-forked, Ro-tax-powered white machine with contem-porary styling and features. A safety sad-dle smoothly contours up on the slim tank.Travel is plenty long, with over 12 inchesat the rear and almost 12 at the front. AMikuni carb, five-speed transmission andMotoplat ignition are headline features. Itdiffers from the KTM Rotax engine in thatthe Sonic displaces 497cc's, while the KTMdisplaces 504cc's. The difference is a mere.6mm difference in stroke. Most of the en-gine parts are interchangeable, but totallydifferent cams are found in both bikes andthe engine performance is dissimilar.

HONDA XRsOORAfter sitting on its basic engine for three

years, Honda has come out with a newangled radial-valved engine with increased

Plush forks, too soft lor MX but pedectlor trailing, soaked up terrain nicely' The

275.5tlickedf dying.

',r-

4

Taller riders telt that the lT was a littleuncomtoftabte due to high pegs and alow saddle height. Average height andshorter riders had no complaints.

...,1

....44'

g

horsepower. The familiar Pro-Link suspen-sion is at the rear and beefy forks can nowbe found up front. Naturally, the forks andshock are completely adjustable.

A sanitary disc brake provides the stop-ping power up front. Travel at both endsis right at I I inches. The XR went on a dietand lost some weight from last year. TwinKeihin carbs smooth out the power de-livery, which is transmitted through a hve-speed gearbox. Fresh plastic and an electric-blue safety saddle top off the all-newpackage.

KTM 5O4MXLast year, KTM enjoyed the distinction

of being the only truly serious four-strokeavailable. This year, it has competitionfrom all fronts and meets the challenge withonly minor iehnements. The 504 Rotax en-gine is Bing-carbureted and Motoplat-fired.A single Fox shock is at the rear, with ad-justable compression and rebound damp-ing. Zoke forks straddle a powerful Brem-bo disc brake. Travel is right at 12 inches,front and rear.

The slim and clean-looking 504 sharesthe same plastic as the MXers. An alumi-num swingarm graces the rear erid. Twoversions of a SuperTrapp exhaust are avail-able, with the larger one being quiet enoughfor woods work. While intended as a se-rious "play" bike, the KTM can hold itsown in a motocross race or, with a speedoadded, can perform well in a Western en-duro. It's perhaps the easiest starting of allfour-stroke big bikes produced.

YAMAHA TT6OOAfter stagnating for years with a basical-

ly unchanged TT500, the TT600 is a breathof fresh air for Yamaha fans. Twin TKcarbs give the engine ultra-smooth low+ndpower, but the engine also pulls hardthrough the mid-range up to stratosphericrevs. Almost 12 inches at the rear and closeto ll up front provide enough travel foranything but pure MX work. Saddle heightis very low and the TT600 is lighter thanits predecessor. Beefy forks and the latestMonocross rear end are pluses.

Super double-leading shoe front brakeshaul the heavy 600 down from speed. Thecrisp white plastic is accented by a redframe and black trim. Tiny lights at bothends add to the enduro capabilities; a toolbag and hand protectors are stock. Eventhough the engine is based on the oldXT550, it has a whole lot more horsepowerand is said to be about ten pounds lighter.Bash bars make for good rock protectionfor desert and hare scrambles racers.

POWERTo determine which bike was the fastest,

we ran good old-fashioned drag races. Formaximum fairness, all races were done witha rolling start, side by side in second gear.This reduced rider skill as a factor as muchas possible. And to eliminate surface varia-tion/tire effectiveness, the drag races weredone on clean, level pavement.

Surprisingly, the KTM emerged as thewinner. We say surprisingly because, whenthe bikes are ridden on the track, both theTT600 and the XR500/eel faster. During

A wide tanklseat iunction takes somegetting used to.

fallest of the bikes, the Can-Am nras lessdesirable in the corners. Strn, tt turns allilght once the rider gets torward andcommits himsell.

the races, the Can-Am would always stayvery close to the KTM, usually about halfa length back. The TT600 and the Hondawere very close, with the Yamaha invari-ably edging out the Honda.

We also rode the bikes on tracks, uphills, through long sand washes and onhard-packed fire roads. But the drag raceswere the moi;t dramatic yardstick. One in-teresting note: We also did top-gear roll-ons with the bikes. Here, the KTM cameout on top again, with the TT600 in second,the Can-Am third and the XR500 last.

If you had asked our testers which bikewas the fastest through the gears before thematch-up, opinions would have been splitbetween the TT600 and the XR500, as bothof these bikes have quicker-rewing per-sonalities. However, the impartial strip ofcement and numerous runs showed theKTM to be the strongest ofthe four, frompoint A to point B.

USABLE POWERAll four of the test bikes had plenty of

power and good torque, but as noted in the

Because the Katoom weighs 11 poundsheavier than the Honda, flight anticsweten't nearly as contidence inspiring.

Of all the strokers, the Yamaha got toppoints for the best-tuming machine. Picka line and go lor it,

drag race test, they all came on different-ly. The Honda pulled fairly clean downlow, surged nicely through the mid-rangeand rewed out wildly until the valves pro-tested. It made its best power from mid-range on up.

The Can-Am had a large blast of powerdown low, then a massive rush in the mid-range followed by a sudden flattening outof the delivery. To make the Can-Am go

1983/DIRT BIKE SUMMER SHOOTOUT SPECIAL 11

quickly you had to short-shift it. It was thehardest of the four bikes to use at slowerspeeds and trailriding would definitely takea talented touch.

Based on the old XT550, the new TT600is quite a motor. It pulls cleaner from thevery bottom than the Honda and has moremid-range and about the same rewingabilities as the XR. There's just a little moregrunt everywhere with the TT than the XR.We found that just about every corner ona test MX track could be taken at least onegear higher on the TT than on the XR. TheTT was also smoother at the very low revsthen all the other bikes. Carburetion was,as we say in the journalism game, "spot-on,tt

Now basically a two-year-old design, theKTM had a monstrous rush of low-endpower, a decent surge at mid-range andrevved out further than the Sonic, but notas far or as hard as the XR or the TT. Onecould not call the KTM smooth at lowerrevs, and trailriding would be a chore.However, the surplus of pure ponies atlower revs makes it a hill eater.

FORKSBoth the KTM and the Can-Am have

Marzocchi forks. On the KTM, they'refirm but acceptable. On the Can-Am,they're harsh.

Trail riders will like the forks on theHonda, but they're far too softfor charg-lng through the rough stuff, as delivered.Raising the oil level will help matters con-siderably. The best word to describe theoverall action of the forks is "plush. " Forfamily enduros and woods riding, the forkswould give maximum comfort.

Firmer than the XR forks, the Yamahaforks also felt supple, but would need araised oil level and,/or heavier springs forracing.

Rating the forks calls for two thoughtprocesses. Ifyou plan to race the bikes, theKTM forks would be the first choice, withthe Yamaha second, the Honda third andthe Can-Am last.

For trail,/fun riding, rate the Hondafront end first, the TT600 second, the KTMthird and the Can-Am's tubes last.

REAR SUSPENSIONIn stock trim, .the Honda had the best

all-around feel tci the rear srispension, butwhen pushed, the Showa single shockshowed signs of fading within 20 minutes.For casual riding, you'd be hard pressedto find a more supple-acting rear end. Forracing, a heavier spring would be a must,even for enduro work. Ifanything, the XRrear end is too plush and approaches a con-dition of wallowing when the bike is press-ed to or near the limit.

A lot of work was put into the rearsuspension of the TT600. It has the abilityto take hits better than the XR, but mustbe rated as a bit harsher overall. It is stillan excellent all-around setup and any num-ber of Yamaha accessory springs are avail-12 DIRT BIKE SUMMER SHOOTOUT SPECIAU1983

able to cover most needs. The TT600 rearend was also fade free and the adjustabili-ty and accessibility are top rate.

It's hard to believe that the Can-Am hasan Ohlins shock on it, as the action isharsh. It will take a big hit without bottom-ing, but medium bgmps are confusing tothe existing valving. We know that Ohlinscan be made to work, but it appears-atfirst glance-that the Sonic has too muchcompression damping and needs a stouterspring.

A Fox Twin Clicker does the job on theKTM. While this is a truly adjustableshock, we were never able to get ours tofeel plush over the small bumps. It handl-ed the medium and large bumps just fine,but chatter and stutter bumps gave the rearend fits.

Overall, we'd have to rate the Honda andthe Yamaha tied for first, with the KTM

third and the Can-Am last. For pure rac-ing conditions, the KTM would be ourchoice.

BRAKESTwo of the test bikes come with disc

front brakes: the KTM and the Honda.Call it a tie for stopping power here. TheYamaha has a great set of double-leadingshoe brakes up front and must be rated ex-cellent. The stoppers on the Can-Am aremore conventional and must be rated as

merely okay.COMFORT AND LAYOUT

Give the Honda the nod for first placehere. Everything is properly placed, withno weird shapes, protrusions or bumps tobother the rider. Those stock bars felt a bithigh, but that's easily changed. The KTMwould have beaten the Honda in this de-partment had it not been for the rock-hardsaddle. It's a trim, slim bike, and with the

Spot-on catburction rets the TT pull agear higher without any coughing orstrange hitches, Also, the Yamaha rcwedlike a banshee, giving it powertd mototlrcm top to bottom.

trlo doubt as to which bike is the tastest,the KTM pulls harder and strongerthtough ttte gears.

Trailriding the big Sonic is out ol lhequestion with a powerband that hits realhard and has a sllght hitch at the bot-tom. Fot motoctoss, it's fine.

ftarsh suspension on the Can-Am drewlire lrcm lhe testers. No manet what lheslze ol the iumP, the tanding hun'

Great rubber, ltfX sel-up suspension anda long wheelbase make the KTM a stablehandler.

.. it&.............,

'*wr.

'9:',?

,Ez

The DB tesl crew.' Phil Beckling/KTM, Wollman Webb/Honda, Randy Russell/Can-Am,OliYet RahleinlYamaha.

tial but unerringly accurate (to plus orminus .0000001264 dingleball) Dirt Bikescales had to say:

Honda ......275.5 lbs.Yamaha .....280.0 lbs.KTM . ...... 286.5 lbs.Can-Am. ....275.5 lbs.

Even with all of the improvements for1983, it's clear that big four-strokes are stillway too heavy. Every one of these bikesshould be at least 20 pounds less in the porkdepartment.

TURNINGRate the TT600 as the all-over best-

turning bike of the group. It was easy toplace the front wheel anywhere in a corner...and easy to keep the line on or offpower. Truly remarkable steering! TheHonda was the next-best-steering bike. Itfelt light but was a bit more twitchy thanthe TT. It seemed to have a mind of its ownon the loose surfaces.

Third rated, the KTM steered well in theturns but responded slower, and the steer-ing was definitely heavier than either theHonda or the Yamaha.

In fourth, the Can-Am steered well onhard-packed ground, but floundered bad-ly on anything loose. Much of the blamemust go to the Pirelli Pentacross tires,which are not much better than bare rims.

STABILITY AT HIGH SPEEDSOVER ROUGH GROUND

We top rated the KTM in stability. Ittracked straight and true, even when hit-ting whoops at speed. The chassis had tobe called rock steady.

Give the TT600 second place here. Itworked quite well in the upper gears, withonly a trace of the feared Yamahop onsquare-edged bumps.

Close to the Yamaha, the Honda work-ed in a reasonable fashion at higher speeds,but it would hunt around a bit more thanthe Yamaha. Not enough to scare the rider,but enough to make him hold on a bittighter than necessary.

In last place, the Can-Am shook its headat speed unless under heavy power. In atrailing throttle situation, the headshakewas almost a full tank slapper. Poor.

EASE OF RIDINGIt's close, but we rate the Yamaha as the

easiest big four-stroke to ride, followed bythe Honda. A low saddle height and super-ior power right at the very bottom of therev range make the difference. Also, withits surplus of flexible power, the Yamahacould be ridden at least one gear higherthan the Honda in the same circumstances.

Third placed, the KTM took more con-centration to ride than the Yamaha or theHonda. It responded to direct input andwould not tolerate sloth or laziness on thepart of the rider. Work the KTM aggres-sively, and it would respond; daydream,and it would flounder.

The Can-Am took a great deal of con-centration and physical effort to ride quick-ly. The power was more of a blast than asmooth delivery. Handling shortcomingsdemanded constant corrections from therider. Very tiring overall.

1983/DIRT BIKE SUMMER SHOOTOUT SPECIAL 15

standard KTM 2.5-gallon tank, the ridercan move around easily on the machine.

With its low saddle height, the Yamahais comfortable for a medium or shorterrider. The bars are far too high and thetank is a bit on the wide side. It's not realeasy to slide up on the TT600 for maximumcornering efficiency. Last place for com-fort and layout belonged to the Can-Am,with its tapered saddle blending into thetank at a high, flat angle. Still, it's not abad-feeling bike when sitting on it.

MONEYA matter of concern to us all: bucks.

There's a big spread between the costs ofthe four thumpers:

Honda. ..$2298Yamaha .92299KTM.. .. $3095Can-Am . $3120

Quite frankly, we don't think the Rotax-engine bikes are worth as much as $1000extra.

READING THE SCALESThe needle reveals all. We weighed the

big four-strokes with no gas in the tanksbut with all the normal oils in their re-spective containers. Here's what the impar-

Start action with Webb on the XR, Oliver Rahlein on the Yamaha, Phil Flickman onboard the KTM and Mt. Dickman's cohort, Randy Russell, straddling the C-A.

BUGSFlaws. That's what we're talking about

here. Probably the least-flawed bike overallis the Yamaha. Other than the aforemen-tioned quirks, the TT600 proved to be afairly complete and polished package.

Give the KTM second place. We down-graded it slightly for the less-than-stellarperformance of the Bing carb. AIso, the oilfill plug blew out a few times. The Can-Am's plug is screwed in. Either stock KTMmuffler will melt the rear fender/number-plate combo.The rock-hard saddle is both-ersome. The kickstarter hung up at the bot-tom of the stroke quite often. There's arat's nest of surplus wiring under the tank,no doubt left over from the GS model.

The Honda is in third place because ofpoor shifting, a slipping clutch (when abus-ed) and the use of the same weak clutchbasket that destroys itself under an aggres-sive rider. We also don't care for the Hon-da cam chain tensioner and find many ofthe engine fasteners weak and undersized.It can also be one of the hardest-startingbikes in the universe if it takes a mindto. . .which it frequently does.

List the Can-Am last. It comes with anopen megaphone and a pipe routing systemthat touches and melts plastic in threeplaces. Attention to detail, in general, islacking. There's no compression release toaid starting and the big engine can oftenbe reluctant to fire, especially when cold.The choke is hidden deep under the bowelsof the tank; a talented finger is needed toactuate it. The gas cap hooks on by one

thread of the tank and leakage is normal.A non-adjustable brake pedal is hard toreach. Handling and layout bugs havealready been covered. And the $3 I 20 pricetag is in the Twilight Zone.

SPECIAL FEATURESBoth the TT and the XR get plus points

for having enduro lighting and instruments,as well as functional tool bags. The TT hasbash bars to keep the rocks away from ten-der cases, while the XR has a sano skidplate. A nice disc brake is a bonus for theHonda, while the twin-leading shoe of theYamaha is super, too.

A Brembo disc brake on the KTM, whileheavy, is nonetheless a superb stopper. TheFox Twin Clicker shock is top-line stuff,as are the Metzeler tires at both ends. Sunrims are inside those Metzes, by the way.And the KTM is perhaps the easiest start-

I6 DIRT BIKE SUMMER SHOOTOUT SPECIAIJIgS3

MOTOnfrCLE tNOUStFy COUNCTLi rNC *c

EIass. JUMP into the WINNER,S CIRCLEthis year with some help from the RussDarnell Motocross School. So farwe've traveled to 52 countries and all 50states. Wewill be teaching near YOU in1983. The 1983 schedule is now ready.Write or call for your copy. We guaran-tee to make you safer and fastet. c

Auqusr 1 5 Snake Creek Auglsl 22-26 Slnrse Cycte ParkCarollon, Geo.gia Adell.nto, Calilo.nia

Auqusl S r2 RD Aravo Auqusl 29 Seplember 2 SaddlebackHouslon, Teras Orange county, Calllo.nia

Russ DarnellMotocioss

SchoolsP.O. Box910 Alta Loma, CA91701

71+9,m,-3212

18 DIRT BIKE SUMMER SHOOTOUT SPECIAU1983

"Okay, everybody line up and go overthe iump side by side!" Wouldn't youknow, not one ol them got any aiL but

-we couldn't repeat this shot it we tried.ll Beckman's neck were an inch shorter,we'd have missed him completely.

ing of all the big bikes. Also, there are anumber of big tanks available for theKatoom that will give it incredible range.The entire rear section unbolts from theKTM for easier shock servicing, a definiteplus.

Give the Can-Am points for having aRotax engine that should prove to be reli-able and easily hopped up to big horse-power. The Can-Am also has an Ohlinsshock, which is very adjustable, dnd op-tional springs are available.

EFFECTIYENESS, RACINGAND FUN RIDING

For pure racing, it's hard to beat theKTM. It's chassis and suspension are setup for charging, not trail riding. Here'show they stack up:

Racing only Fun ridingl. KTM l. Yamaha2. Yamaha 2. Honda3. Honda 3. KTM4. Can-Am 4. Can-Am

THE BOTTOM LINEOverall, we have to rate the Yamaha

TT600 as the best choice. We think theKTM is a better bike, but not nearly $1000better. Give the Honda second spot for thesame reason. If you can get a deal on theKTM where the price is more in line withthe Honda and the Yamaha, then go withthe KTM. If not, there are a lot of trickHonda and Yamaha speed and suspensionparts that can be bought with $1000.

The Can-Am is last, for obvious reasons.If you're on a budget, rate the bikes:Yamaha, Honda, KTM, Can-Am. If youjust got a big tax refund, rate the bikes:KTM, Yamaha, Honda and Can-Am. Thatshould be clear enough for even the mostrabid four-stroke freak. n