Race Preparation

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By mid-February 1973, at least a cou-ple of dozen new water-cooled YamahaTZ 350s had been delivered to shopsaround the country and were being pre-pared for Daytona. You could havewalked into any of those shops at anystage in the preparation process withoutfinding substantial differences in the de-tails of the work being done. Most of theeffort expended was being devoted to en-gines! and most of the engine work in-volved nothing more elaborate than mi-nor surgery to correct casting flaws andmismatched edges in the ports. None of itwould have been unfamiliar to anyonewith experience in the preparation oftwo-stroke engined competition bikes ex-cept the mundane business of fitting fair-ings-an activity filled with fiberglassdust and itching which the motocrossbrigade happily avoids.But if the pre-Daytona work per-

formed was virtually identical, the ob-servable result of those labors was not.All of the TZ 350s were motoring aroundin Bill France's sandbox rather rapidly,but some were vastly more rapid thanothers. As expected, Kel Carruthers'Yamahas absolutely flew, giving away lit-tle in sheer speed to the best 750cc Ka-wasakis and Suzukis. Also expected werethe grumbled complaints from the lowli-er privateers, some of whom swore thatthe TZ 350 just naturally wasn't as fast aslast year's air-cooled Yamaha 350 and allof whom seemed convinced that Carruth-ers' contract with Yamaha Internationalgave him access to Trick Stuff malicious-ly being withheld from everyone else.Such talk may have made the privateer

tuners feel better about themselves, if notoverly optimistic about their prospectsfor success in the contest at hand, but italmost certainly had no foundation infact-and it was self-defeating to the ex-tent that it obscured the truth. And intruth, the real advantage Carruthers en-joyed was in the lavish stock of sparesprovided by Yamaha, a first-rate team ofriders, and especially in his own solidskill as a tuner.After handcrafting a number of genu-

ine Daytona disasters in years past, I amnot much inclined to claim solid tuner'sskills. Even so, the Yamaha TZ 350 Iprepared for Jess Thomas here in Cycle'sshop was one privateer entry that gave

raceprepara t ionCome on now, admit it: a lot of you who might be fresh tothe sport of motorcycling already have the beginnings of a big,mangy rat growing in your souls whose name is Racing and whofeeds on speed. What follows will help you spend more timeon the track and less time staring at melted pistons, seizurestreaks, twisted connecting rods and blown head gaskets.

BY GORDON JENN ING S

away nothing in pure speed to Kel'ssemi-works Yamahas and may even havebeen a trifle faster: the Cycle TZ 350 waspulling slightly taller gearing than evenCarruthers' own bike, but then he mayhave been giving away top end in the in-terest of infield acceleration. The pointhere is that Cycle's entry was operating athorsepower parity with the Yamaha-sup-ported stuff, and that this was done with-out recourse to special hardware.Indeed, not only did we prepare theCycle TZ 350 without Trick Stuff, wehad no spares of any kind until the prep-aration process had been completed. Formost privateers that would have been ahandicap; for us it was a positive advan-tage. When you have no spares for yournew zoomer and must face the possibilitythat they may be in short supply evenafter becoming nominally available, thereis compelling reason for restraint in allthe details of preparation. Consideringthe fact that simple lack of restraint hasso often been my downfall in years past,it does seem likely that having it forcedupon me by circumstance was, on bal-ance, a good thing.

That no trick hardware was madeavailable to us should not be taken tomean we had no advantage over otherprivateers. Motorcycle magazines' staff-ers are perfectly situated to learn some-thing new-and/or useful every day, andthose of us who care about high-outputtwo-stroke engines can easily collect awealth of related information. Specialhardware all too often does not evenwork in the application for which it isintended, whereas good information isapplicable in every endeavor from road-racing to motocross.

If nothing else, my contacts with pro-fessional engineers have saved me a com-mon tuner's error, which is to think thatthe slide rulers are either indifferent orstupid. Few are, and it is possible to im-prove upon their handiwork only becausethe scope of the engineers' activities isconfined by a couple of realities. Firstthere is the matter of manufacturing cost,which forbids the application by factoriesof the laborious manual matching ofport/manifold joints and such. Racingparts, just like those intended for ordi-nary touring applications, have to be

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mass-manufactured to plus/minus toler-ances, and it is inevitable that tolerance-stack mismatches do occur. Second, thefactories' development engineers must al-low for the fact that most race-bike cus-tomers aren't gifted tuners, a situationwhich makes the engineers disinclined tobuild ragged-edge engines.Experience may have taught factories

to take a dim view of the average tuner; ithas taught us to keep a close eye on thefactories. However brilliantly the engi-neers may have done their work, it allgoes for naught on a Monday morningwhen the guys on the assembly line sufferfrom hangovers. Mistakes are made andthe worst of them seem to be reserved forracing bikes-perhaps because the pro-duction run is too brief to properly trainthe workers. You are more likely to findassembly errors in production racers thanin their touring equivalents; in conse-quence the first stage of racing prepara-tion is to take the machine apart for closeinspection. That's how we started theprocess with our TZ 350.Along with the expected nubbins and

ridges inside the engine's ports, it wasdiscovered that the transfer tunnels in thecylinder block didn't begin to match thetransfer troughs cast into the uppercrankcase half. The reason? Yamaha usesthe same crankcase castings as in thestreet-going RD 350, which has separatecylinders and is somewhat pinched fortransfer tunnel area between the two air-cooled cylinders. Casting the water-cooled cylinders in a single block allowedthe inner transfer passages to share a sin-gle separating wall, and they could there-fore be very perceptibly enlarged. En-largement there also permitted increasesin the size of the outboard transfer pas-sages. There obviously was no direct, me-chanical restriction on the size of theseouter transfers. The restriction stemmedfrom the need for symmetrical flow pat-terns inside the cylinders, which requireda matching symmetry in the size andshape of the transfer passages. Thus thecrowded.con di tion between the air-cooled Yamaha's cylinders dictates theform of all its transfer ports.Those ports are larger in the water-

cooled TZ 35(}, and have a better shape.For that reason, even though enlargingthe air-cooled engine's transfers does pay

PHOTOGRAPHY: DALE BOLLER

NOVEMBER 1973 71


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power dividends, I confined myself to justsmoothing casting flaws inside the transferpassages and trimming the crankcase trans-fer troughs to match. My feeling in this isthat Yamaha (and most other manufactur-ers) can cast better port shapes than I cancarve. Only when something is clearly thecreature of manufacturing convenienceshould substantial amounts of metal be re-moved. One such area was an abrupt step inthe exhaust port spigot where the cast sur-face ended and the machining began. Thisstep appeared to be the result of expediencyrather than planning, and it is generally ac-cepted that any abrupt changes in cross sec-tional area in exhaust ports create sharp sec-ondary reflections tending to spoil the pow-er-augmenting wave activities generated byexpansion chambers. Another area of re-shaping was at the ribs separating the maintransfer ports and the boost ports. These ribsare squared off in the machining of the cyl-inder base, and most of the people who pre-pare racing Yamahas trim the divider ribs toa knife edge. That almost certainly is thewrong approach: knife-edges are fine in su-per and hypersonic applications, but flowrates at the transfer passage entry are sub-sonic, and a rounded shape like that of alight aircraft's vertical stabilizer seemedmore appropriate, so that's what I use.Gross irregularities are easily detected,

but the workers who build these racing ma-chines are diabolically clever in hidingsmall, nasty mistakes. You'll become posi-tively paranoid after preparing a few newracing engines and encountering transmis-sions unaccountably shimmed to give onlypartial gear engagement, tight and dry oilseals, piston rings installed inverted and/orwith their end gaps too narrow or too wide,and sundry other such surprises. Yamaha'smachines are somewhat less likely to havethese built-in traps than those of most oth-ers, but even Yamaha isn't perfect. If it'sperfection you want, you should be willingto give time for the complete tear-down andreassembly process.One of the most important items in the

preparation of a racing two-stroke engine isone that a factory would find almost impos-sible to handle in advance of delivery to thecustomer. Two-stroke racing engines havevery wide exhaust ports and their ringsbulge out into those ports every time the pis-ton sweeps down to bottom center. Therings would be broken on the next upstrokebut for the shallow chamfers ground aroundthe port windows. These chamfers ease therings back into their grooves and should be(but never are) completely free of snags andrough spots. Careful tuners will smoothaway any sharp edges with fine-tooth toolmakers' files and polish the chamfers with avery fine grade of emery cloth. Chromed-72

bore cylinders, like those in the TZ 350 en-gine, present a special problem because thechromium plating is very thin, and the cylin-der will be ruined if the underlying alumi-num is exposed. When working withchromed cylinders, use fine emery cloth-or, better still, round-section jewelers'stones-and just polish the chamfers. Giveparticular attention to the edge between thecylinder wall and the chamfer, as a sharpridge of chromium builds up there duringthe electroplating process. This ridge is notentirely removed in the subsequent precisiongrinding operation.Even though the exhaust port is the most

likely to suffer ring snagging, this can alsooccur in the transfer ports, and those cham-fers should also receive close attention. Andyou will usually find that a few small spotswill have eluded your searching eyes and fin-gers. These invisible snags will reveal theirpresence in the scratch marks you'll see onthe rings after the engine has been run harda few minutes. You then will know wherethe port window chamfers need added atten-tion, and although perhaps a half-dozen fullcycles of running, checking and polishingmay be required to get things perfect, theresults are worth the effort. Do it right andthe rings will retain a nice, clean sealing facemany times longer than otherwise would bethe case.Racing two-stroke engines are very sensi-

tive to ring sealing. Blow-by drops poweroutput by diluting and heating the freshcharge down in the crankcase, and blow-byis directly responsible fo. almost every in-stance of piston seizure. People more or lessassume that seizure occurs when overheat-ing causes a piston to expand until it is effec-tively larger than the bore itself, a press fit.Investigation has shown that not to be thecase. Indeed, so long as the piston skirt isadequately lubricated, seizure will not occurat all, though the pressures created by ther-mal expansion may be so high that thewhole piston may deform. Unhappily, thepiston deformation often includes a verticalsmearing of metal around the ring groove,and that in turn locks the ring so that it losesits ability to seal. When that happens thehigh-temperature combustion gases are freeto blow down past the piston skirt, whichscorches away the oil film, and piston sei-zure follows that breakdown of lubrication.The mechanism of piston seizure being

what it is, it becomes clear that the devicemost often employed as a countermeasure-larger piston/cylinder bore clearances-islikely to make the problem worse ratherthan better. A loose-fitting piston is apt torock too much to allow the ring to seal de-cently, and it offers an unobstructed path forany high temperature gases that force pastthe ring. Piston clearances in the TZ 350 en-

gine are only .040-.045mm, or less than.. 00l-inch, and this Yamaha is neither as fastnor as reliable when its pistons are a looserfit. Of course, it is water-cooled and has alu-minum cylinders with an expansion ratevery near that of its pistons, and engineswith air cooling and/or iron cylinder linersneed more clearance for their pistons-though often not as much as they are given.While on the subject of pistons, seizures

and the like, I will confess to being appalledat the average two-stroke tuner's passion foreconomy in the amount of oil fed his en-gines. Nearly 10 years ago I learned from aprofessional engineer that his firm's powercertification tests were run using a 10:1 gas-oline/oil mixture, and he added that theymight go to even higher percentages of oil ifmagnetos and spark plugs capable of firingsuch rich mixtures became available. He ad-mitted that rather less oil was desirable un-der actual racing conditions, because of plugfouling problems with the 10:1 mix, but in-sisted that maximum performance was ob-tained with the largest percentage of oil theplugs would tolerate. Subsequent experienceand further investigation have convinced methat he was absolutely correct, and it's nowmy practice to feed any two-stroke racingengine as much oil as its ignition system andspark plugs will handle. Any doubts I mayhave had about the wisdom of this approachwere resolved by more recent data obtainedwith elaborate instrumentation: test resultsclearly showed that cylinder wall and pistontemperatures are elevated as the percentagesof oil coming in with the fuel are reduced,and the engine cools as more oil is added.Power output follows closely the tempera-ture changes, but in inverse ratio of course.It should be noted here that oil-test proce-

dures, whether the samples tested vary inkind, percentages added to fuel, or both,must include carburetor adjustments to givemaximum power with each individual sam-ple. That is to say, you cannot use the samecarburetor jetting to test Brand-A againstBrand-B, or the merits of a 15:1 fuel/oilmixture against one mixed to 20:1 propor-tions, and then expect that the results willhave any validity. This aspect of such testingis often overlooked in individual efforts todetermine which oil, or mix ratio, representsthe optimum.Outside the cylinder bores, the engine will

like a fairly high-viscosity oil. Rolling-ele-ment bearings employed in these engines arerelatively indifferent to the amounts of oilthey receive, but they are sensitive to oil vis-cosity. Bearings of this kind last longer whenfed a trickle of 50-weight oil than when del-uged with 20-weight. Sadly, in this regard,the bearings and piston rings are in funda-mental disagreement. Heavy oils extend(Continued on page 85)

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BASICS Continued from page 72bearing life; they also tend to form ring-sticking gums and varnishes. My own in-clination in this matter is to use the thick-est oil possible consistent with the absolutenecessity for keeping the rings free in theirgrooves. For roadracing engines, in whichfrequent replacement of pistons and ringsis necessary no matter what oil one selects,I favor 4O-weight Castrol racing oil. Thiscastor-based lubricant is relatively clean,provides excellent protection against pis-ton scuffing and bearing failures, andseems to form a seal between the pistonand cylinder bore that blocks the passageof any gases leaking past the ring. Its onlydrawback is that it mixes with gasolineonly reluctantly and will promptly sepa-rate from this fuel if the mixture is cooledbelow about 50F.In applications other than roadracing,

where temperatures and pressures are like-ly to be less extreme, there is much to besaid for thinner, more thoroughly de-gummed castor-based oils (Blendzall beingone of my favorites). The degummingprocess used for all castors intended as mo-tor oils tends to make them less effective aslubricants, but also burn cleaner. Some-times the cleanliness of triple-de gummedcastor is more important than its in extre-mis lubricating properties. An importantfact to remember about all castor oils isthat they oxidize very rapidly when theyate exposed to air, and cannot be reliedupon to stay in solution in gasoline for pro-longed periods. Therefore the gas/oil mixin your bike's tank becomes more unreli-able in its intended purpose with eachpassing day and should be drained and dis-carded after no more than 48 hours. Petro-leum-based oils mix perfectly, stay mixed,retain their lubricating properties oververy long periods, and for those reasonsare an excellent choice for the averageWeekend Warrior.Among the several small items a tuner

should check and adjust (but few do) is thepiston crown/cylinderhead clearance inany engine with a squish-band combustionchamber configuration. The purpose of thesquish band is to confine the mixture in thecombustion chamber to a small pocketright under the spark plug. When this isdone higher compression ratios than wouldotherwise be possible may be used because:a) the charge around the edges of the cylin-der bore are spread too thinly to be deto-nated by the advancing flame front; and b)the piston crown area directly exposed tothe combustion process is reduced, yield-ing a reduction in the amount of heatforced into the piston. On the other hand,that portion of the charge hidden away inthe squish band is substantially wasted,which is the squish head's single drawbackand a compelling reason for making thesquish clearance as small as possible.Clearances as close as .015 have been em-ployed experimentally but something near-er .040-inch is less likely to bring the pis-NOVEMBER 1973

P U T Y O U R H E A D W H E R EY O U R H E A D IS .

W i n d - s w e p t d e s ig n a n dw i ld c o lo rs s p a rk th eim a g i n a tio n . Y a m a h a g iv e sy o u o n e o f th e la r g e s ts e le c t io n s o f h e lm e ts inth e in d u s t r y , le ts y o up ic k ju s t t h e r ig h t h e lm e tto m a t c h y o u r m o o d o rm a c h in e . T h e s e g re a tlo o k in g h e lm e t s a re th em o s t c o p ie d o f a ll d e s ig n sa n d t h e y r e m a in t h e t o ps e l l e r s .

O u r c o m p le t e l in e o fY a m a h a h e lm e ts a req u a l i t y f ib e r g la s sc o n s t r u c t e d , th e y e x c e e d

Z 9 0 . l s t a n d a r d s a n d a r eS H e A c e rt i f i e d . O u r fu ll ~:,c o v e ra g e h e lm e ts a reS N E L L a p p ro v e d , ( t h e r ea re n o b e t te r a p p ro v a lsa h e lm e t c a n g e t ) . F lip -u pfa c e s h ie ld a n d t e a r - o ffm u d le n s a re s ta n d a r do n a ll f u ll c o v e r a g eh e l m e t s .

S e e t h e c om p le tes e le c t io n o f Y a m a h ah e lm e ts a n d t h e e n t i r ec o lle c tio n o f a c c e s s o r ie s ,s p e c ia lt ie s a n d a p p a re ln o w a t y o u r Y am a h ad e a l e r .

Y A M A H A P A R T S D I S T R IB U T O R S , I N C .A subsidiory of Yamaha International Corporotion

6610 Orangethoroe Avenue. Bueno Pork Coliforr::o 90620CIRCLE NO. 48 ON READER SERVICE PAGE 85


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ton crown and cylinderhead into direct sealing properly, and all is right with the quire a first rate ignition system-like the;;j contact at high revs. More clearance is sel- world. Because we were dealing with an TZ 350's pointless CD magneto-and thedom necessary, as it simply wastes more of unknown (the high compression) at Day to- right spark plugs. And here again I'll say~r the trapped charge, and squish bands cease na, much time was spent sending Jess out that the recessed-gap racing plugs madeto function as such when the piston/head to do a few laps and then dismantling the for four-stroke engines are a bad choice forclearance is much above .060-inch. engine's top-end to check the condition of two-stroke engines. Champion now has anThe TZ 350's squish clearances were a the piston. This was very time consuming, extended nose racing plug that is far less

mighty .Q80-inch, or about twice what my but necessary. By taking this approach it . . foul-prone than those of the traditionalexpert advisers consider desirable. A call was possible to catch problems in the in- racing pattern, and I found at Daytonato Yamaha International's racing depart- cipient stage, before they could develop that the Champion E-55 was an absoluter ment yielded only the information that this into an expensive explosion, and it gave me marvel. Even with the dense fog of fuel andcondition was typical, others having dis- a chance to work the last, invisible rough oil our TZ 350 was getting in its cylinders,covered the same thing, but that there was spots on: the port window chamfers. we could use the Champion E-55 plugs forno explanation from Japan. Typical as it One of the things that was revealed in both warmup and racing without the\ \ ; may have been, I didn't think it was right, these inspection tours through the engine slightest trace of loading or fouling. Subse-and finally concluded that the whole thing was that the spark advance specified in the g quent experience showed that slightly bet-~~was a Yamaha 'effort to save the customer TZ 350 owner's manual was too much for l ter results were obtainable on shorterfrom himself. The clincher in reaching this the high-compression version to tolerate. courses with the marginally warmerconclusion was that an SAE paper au- Theory predicted that this would be the ! Champion N-214, but at Daytona the E- l i . . .

J thored by Yamaha's ranking engineers case, due to the increases in flame propaga- 55s were by some considerable margin the ' "ave a compression ratio of 8:1 (taken tion speed produced both by the higher best plugs we tried. It is my practice to t;. , from exhaust-closing) as suitable for this combustion chamber pressures and the en- always use the hottest plug, richest mix-kind of water-cooled racing engine. Calcu- hanced turbulence stemming from the re- ture and most oil an engine will stand, and ,lation showed that if the combustion duced squish clearances, and this was con- Champion's latest racing plugs have per- lhamber had been milled just a millimeter firmed by the appearance of the spark mitted a quantum leap in that direction.\ shallower, giving the right squish clearance plugs and pistons. Pulling back the ignition While at Daytona, we learned that Kel ~f .040-inch, then the compression ratio advance to 1.9mm BTC (from 2.0mm) Carruthers probably was using the same.. '~ would have been almost exactly 8:1. changed the spark lead by no more than high-compression setup we found so effec-.> All this seemed to be too much for mere three degrees, but that was enough to elirn- tive. Kel got a shipment of heads from Ja-_ " coincidence, so I finally decided that while inate all signs of overheating. At that point pan early that week, and those heads did- - - shaving a millimeter off the underside of the varnish up inside the piston was jet have squish bands about a millimeter shal-our engine's cylinder head might not be as black, but not charred, at its center and lower than the standard TZ 350 heads. Kelgood as having the combustion chambers faded out into the characteristic shades of denies that these cylinderheads were ma-

.reter machined less deep in the first instance,it chocolate and tan at the edges. I might add chined to give a higher compression ratio,firm was better than having a compression ratio here that the color of this varnish is virtu- claiming that only the squish clearances

sctes of less than 6.5: I and squish clearances so ally an absolute gauge of compression ra- had been altered. An informant insidevioes deep as to present virtually a wide-open tios. You can raise an engine's compres- Yamaha told us that Kel's special ship-igue. combustion chamber. The extra-deep sion ratio until the varnish in the middle of ment definitely was high compression ind. of chamber just seemed entirely too much the piston crown's underside turns as black intent, and that we had been exactly rightlales like something Yamaha might have decid- as a race official's heart, and if you've done with our early guess. Who knows? Foras ed upon at the last minute as a safety de- everything else right, you won't have to sure Kel was sufficiently intrigued by ouroat tune in engines destined for customers who worry about reliability unless the varnish Yamaha's speed to drop by our garage tomight not give close attention to such begins to char. That's the danger point. see what kind of gearing the bike had-andered humdrum matters as jetting and ignition Obviously, doing everything else right is actually counted the sprocket teeth tofrom settings. Frankly, I have made my share of a trick not everyone manages-especially make sure we hadn't stamped the cog with:e an mistakes in this kind of work-and rarely as regards mixture strength. You already the wrong number.have missed an opportunity to lunge for- know my feelings about feeding a racing Others have heard about Our bike, andr~ ward and grab an extra helping of stupidi- engine slathers of oil. Our TZ 350's tank have tried it themselves but with very bad~, ty when it was available. But now that I'm was filled with a 14:1 blend ofCastrol40R results. The speed is there, only not for

not riding I have fewer distractions at the and gas, which most tuners would consider very long before checked by a holed pistonJ ; : : r , ; track and have time to gather good advice. totally absurd. Most tuners would, and as or seizure. We don't know for certain, bute This time my sources said the modification many would have been -staggered by the it does seem that other people's problemsunder consideration was going to work, jetting I chose: most of the TZ 350 Yam- result from their not doing everything we

but that I'd better not miss much with ahas at Daytona were running #320 (or did, and our engine was running nearmixture or timing or there would be pieces thereabouts) jets; Cycle's Yamaha was enough to the ragged edge to be intolerant

!:,,,,,,, of engine all over the track. sucking fuel past a pair of #360 Mikuni of leaner mixtures and reduced amounts ofAll that compression was sure to have a main jets. Kawasaki's Mr. Yoshida may oil. There also are some little tricks to getpowerful effect on engine output, and did, not think much of ultra-rich mixtures (see good sealing between the cylinderhead andbut it also had its effect on the amount of Kevin Cameron's Loudon race report, in I I block; anyone who needs this special-inter-time spent twirling wrenches. When you Cycle's September, 1973 issue), but my ex- 'est information can contact Cycle's Westare tuning two-stroke engines you spend perience has been that leaning "down, Coast editorial offices.nearly as much time peering at pistons as down" much below the point of chuffing I "So," you're probably thinking, "if theat spark plugs. The plugs tell you about soot results in power increases-but only Cycle TZ 350 was such a rocketship howmixture strength; the undersides of the pis- in misapplied dyne-testing. There is no come it didn't figure prominently in theton crowns are an excellent indicator of doubt that the engine will cold-flash higher race results?" As a matter of fact, that itimpending trouble. When you see the readings on the dynamometer with leaner didn't is my fault: in getting the bike's en-cooked-oil varnish inside the piston begin- mixtures; rich mixtures provide enough in- gine honed to a fine edge I kept the Yam-

I ning to char, the piston crown itself is dan- ternal cooling to improve sustained power aha garaged far too much and as a resultI gerously near melting. But if the varnish output, and it is sustained power that Jess got far too little practice. His priori-I inside the piston retains its gloss and the counts on the race track. ties, like my own, are of necessity heavily' - : J skirt is smooth and clean, then you know Ultra-rich air/fuel mixtures, with the weighted in favor of time at the typewritertemperatures are within limits, the ring is fuel carrying high percentages of oil, do re- and away from the track, and he hadn't

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been on any racing motorcycle for months.Our TZ 350 was a hair-trigger bullet, andJess wasn't comfortable on it at all. But hewas out there soldiering around and figur-ing to see it through until Brelsford andDarr did their great, flaming catastrophe.Jess saw that through the rivulets of sweatin his eyes and just figured it wasn't a goodday to be working at not having a bit offun. He pulled in and we went off to have acold drink.The only real question about the TZ 350left unanswered by our Daytona experi-ence was, would it last? We settled that byrunning the bike at a local race and at thedragstrip, and by following its progress af-ter it was sold. And our TZ 350 did morethan enough miles to have finished at Day-tona without repairs, and without anyproblem beyond a tachometer bracket fail-ure. The bike's new owner is, we hear, de-lighted with it, and I have passed that in-formation along to people I know who re-ally know what they're doing and who told

me to do exactly what I did. @

ART Continued from page 50painting is essentially decorative-that'sthe main thing. Custom painters aredecorating their motorcycles. Nowdecoration and art are mutually exclusivemost of the time-not always, but theytend to go in opposite directions. Andthat was one of the things that drove menuts doing this bike. I kept trying to makeit look great, but at the same time thatwas almost working against me."On the message: '"I wanted to make

a statement about machines. I thinkmachines are fascinating: I 'v e beeninterested in them ever since I was 'achild. But to me over-involvement inmec hanical things gets kind of fetishisticand nauseating. I've had this ambivalentfeeling all my life about machines. andI wanted to express that in this painting.I wanted to simultaneously celebrate thewhole business of machines and sort ofpoke fun at it. So I did this tongue-in-cheek religious thing. I had this prog-ram of celebrating the worship ofmachinery-and yet I wanted to keep ita little amusing-and I thought the paint-ing was appropriate within the contextof custom painting which has always hada tradition of the bizarre. And (wantedto combine my attitude about this wor-ship of machinery with the general classicattitude about the Triumph. So combin-ing those two, I came up with a classicalsurrealist kind of artwork."If you take the main figure on the

top of the tank, in that figure is probablythe whole spectrum-simultaneouslyserious-looking and ridiculous." @88

NEW S L IN E Continued from page 78Cycle Carrier: Desert Dynamics' new mo-torcycle carrier is designed to carry one ortwo motorcycles and bolts securely in yourtruck. The carrier also' provides room fortwo G.I. gas cans. Your cycles can be pad-locked in place to prevent theft. The listprice is $39.95.Contact Desert Dynamics, 6230 May-wood Avenue, Bell, California 90201.

CIRCLE NO.5 ON READER SERVICE PAGE

Automatic Headlights: In response toCalifornia's new safety bill which statesthat: "Every motorcycle manufactured andfirst registered after January 1, 1975 shallbe equipped with at least one and not morethan two headlamps which automaticallyturn on when the engine of the motorcycleis started and which remain lighted as longas the engine is running," Keen Researchand Development Corporation has a newdevice to accommodate the bill.Known as the Keen "Luminator," thedevice will automatically turn on motorcy-cle lights 20 to 30 seconds after the ignitionswitch is turned on.According to Stan Mutnick, a companyofficial, "The advantage of the time delayfunction is that the rider has time to starthis machine without the drain of his head-light on the electrical system. After start-ing, he is assured that he will be ridingwith his headlight on."Easily installed, the Luminator willwork with either 6-volt or 12-volt systems.For more information on the Luminator,write to the Keen Research and Develop-ment Corporation, 5382 Sterling CenterDrive, Westlake Village, California 91361,or call 213/889-6671.CIRCLE NO.6 ON READER SERVICE PAGE

Cycle Saver: Prevent your bike from beingripped-off with Suitcase Cycle's theft de-terrent. Suitcase Cycle says the Cycle Sav-er is the only theft deterrent which pre-vents the cycle from being ridden ofT.Cycle Saver allows the owner to discon-nect the handlebars and lock them to thefront forks, leaving no means to steer thecycle, and thus preventing it from beingridden away. The Cycle Saver Kit containsquick disconnect brackets, so that the han-dlebars can be 'locked to the front forks.Disconnecting the throttle and clutch ca-

bles is unnecessary.In addition, a built-in lock allows twohelmets to be locked to the bike, prevent-ing their being stolen.The unique Cycle Saver modificationcan be performed on most Honda, Suzukiand Yamaha motorcycles in less than ~nhour. No special tools are required.For further information contact themanufacturer, Suitcase Cycle, at 3013 Air-port Avenue, Santa Monica, California90405 or call 213/390-4421.

CIRCLE NO.7 ON READER SERVICE PAGE

Piston Kit: Convert your Yamaha 650 to a750 with a new kit from Rand Company.Included in the kit are two 10:1 compres-sion pistons with valvecut-outs deepenough to take a .450 lift cam, wrist pins,clips, rings and instructions. The kit isunique in that it needs only a bore job onthe stock cylinder to install it. Oversizepistons are also available. A 15 to 20 percent increase in your Yamaha's perform-ance is claimed by Rand.It costs $79.95 or send in your cylinder

and $99.95 and Rand will bore and preci-sion fit the kit to your cylinder and have itback to you in two to three days. Write the(Continued on page 100)

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