CYCLE GUIDE ROAD TEST

In case you haven't noticed, the HondaCB750 has undergone a major personalitychange since it first appeared in late 1968.It has been gradually and subtly trans-formed from a superbike/tourer into aquieter, slower, more tractable, more reli-able tourer. The ferocity of the firstCB750s was sacrificed to make later mod-els more reserved and nicer to ride. Hondaseemed to feel that their buying publicdidn't care as much about eyeball-flatten-ing acceleration as they did about in-creased convenience and comfort.

And Honda's feelings about what thebuyer wanted were proven to be accuratein late 1974. In a period of severe eco-nomic depression, when almost everyoneexpected the sales of small, cheap, thriftymachines to pick up. the Honda CB750sold better than any other motorcycle.

Honda reiterated their policy of pro-viding the buyer with comfortable, reli-able, tractable, less noisy, mildly-tunedmotorcycles by introducing the GL-1000Gold Wing. That machine wasn't nearlyas fast as it could have been, but it wasplush and easy to live with.

Knowing how Honda felt, we were sur-prised when we learned about the CB750FSuper Sport. This model is engineered tobe significantly faster than the most recentversion of the '"standard" CB750, the K5which we tested in December of 1974. Ontop of that, the Super Sport's styling ismore radical than that of any previousHonda 750. In addition, significantchanges which affect the bike's handlinghave been made, and it has a disc brakeat the rear wheel.

But the real shocker came when welearned the Super Sport isn't being offeredas just an alternative to the standard 750.but that it is actually intended to replaceit. That seemed strange because the SuperSport, if in no other way but image, isentirely different from what we have cometo expect from Honda.

So our first look at the machine leftus puzzled and intrigued. Could it reallyreplace the K5? Is it a mild-manneredroad machine, a potent performancepackage, or something in between? Whatkind of rider is it aimed at? These werethe sort of questions that popped into ourminds when we began testing the Honda750 Super Sport.

THE BIKE: Basically the same Honda750 familiar to so many American riders,the CB750F Super Sport incorporateschanges ranging from the nearly incon-sequential to those which affect the entirepersonality of the machine.

Some of the most obvious changes are

external, and of these, the four-into-oneexhaust system is the most prominent. Thefour header pipes sweep down and acrossthe front of the engine to a collector underthe right side of the crankcases. A largechrome muffler that looks, as one gawkercommented, "like a cross between an ex-pansion chamber and one of those bigHarley pipes" is clamped onto the collec-tor. The muffler is slightly upswept, andits rearward portion sticks out away fromthe motorcycle quite a bit. Honda claimsthe exhaust system adds power and makesthe bike quieter than the four-pipe setup.

In the area of styling there are notice-

able changes in the gas tank and seat. Thesteel tank is longer than the tanks foundon previous CB750s and now holds 4.8gallons, an increase of 0.3 gallons. Thegas cap is recessed under a locking, hingedcover that folds down flush with the tanktop. The thinking here is that a smoothsurface on top of the tank is less likelyto snag something vital on the rider'sunderside if he comes to a sudden stop-like against a truck. A chain attached tothe gas cap insures that you won't forgetit in a gas station, and there is a drainto get rid of any gas that spills over intothe recessed area under the cover.

The hinged, locking seat has a road-racing-styie rear section like the type usedon Kawasaki street bikes. Under the seatback is a waterproof plastic box for carry-ing spares, papers, and other odds andends. The plastic scat back is painted tomatch the tank and a thin, painted stripruns along the bottom of the seal.

Another styling change is in the head-light area. The headlight brackets mountto the triple clamps instead of the forktubes, giving the fork a much cleaner look.The headlight has been given a thinnerprofile, and rubber gaiters are no longerused on the fork tubes.

the compression ratio has been upped twotenths of a point by using new pistons withslightly higher domes. The chain-driven,single overhead camshaft has been altered,primarily to make it more compatible withthe new exhaust system. The intake andexhaust timing has been extended fivedegrees at both ends, and the valve lifthas been very slightly increased. The cyl-inder head bears a new part number, butthe changes in it are minor ones, likelarger studs for the exhaust pipe headerclamps. The four 28mm Keihin carbure-tors also have a new number, but theyseem identical to those found on theK5—even down to the size of the mainjets. The airbox has also been redesignedto be less restrictive.

As in previous CB750s. the F model'scrankshaft rides in five plain insert bear-ings. Power is still delivered to the clutchthrough two single-row chains that drivea jackshaft, but two teeth have been addedto the jackshaft sprockets; they now have50 teeth each for a ratio of 1.985:l. Thewet clutch has been modified to allowmore oil to get at the plates, which is aneffort to reduce the friction plate distor-tion and glazing that make the clutchgrabby and noisy. The seven friction plateshave also been altered slightly and theclutch center has been changed.

The first three ratios of the five-speedtransmission are the same, but the fourthgear ratio has gone from 1.097:1 on theK5 to 1.133:1 on the F, and the fifthgear ratio has been changed from 0.939:1to 0.969:1.

The transmission sprocket has alsoshortened the overall gear ratio by givingaway one tooth for a new total of 17 teeth.It drives the same 48-tooth rear wheelsprocket through a new RK brand chaindesigned by Honda R and D. The chainhas thicker side plates and is made ofacid-resistant metals. (Previous chainsoften broke if battery acid was spilled onthem.) All those gearing changes meanthat the Super Sport's first three gears are23 percent lower than the K5's, and fourthand fifth are 27 percent lower.

the lubrication for the engine, clutch,and transmission is provided by a dry-sump system, fed from a 3.7-quart tankmounted on the right side of the bike. Younow have to remove the right side panelto get at the dipstick to check the oil.

The battery-coil ignition system usestwo sets of points; one set fires cylindersone and four while the other sparks twoand three. The ignition point cam attachesto the right end of the crankshaft and thealternator is on the left end. There is now

A final major external change is theswitch to a hydraulically-actuated discbrake at the rear. The disc is the samesize as the one found at the front, 11.7inches in diameter. The rear calipermounts on the right side of the wheel andis a double-action type; the front caliperis of the single-action variety. A largepolished alloy bracket behind the rightfootpeg provides a mounting point for themaster cylinder and the brake pedal.

Quite a few changes have been madein the four-cylinder, four-stroke. 736ccengine. The bore and stroke remain thesame at 61 and 63mm respectively, but

a crankcase breather which catches drop-lets of oil escaping from the engine andreturns them to the system. The owner'smanual recommends periodic cleaning ofthe foam element found in this basic smogcontrol device.

The Super Sport uses the same basictubular steel, double-loop chassis as pre-vious models. However, the steering headhas been raked out from 27 to 28 degrees.There is a corresponding amount of addi-tional trail, which has gone from 3.7 inchesto 4.5.

The front suspension now has 5.0 inchesof travel rather than 5.6 inches, but noone at Honda knew what internal changesthe factory made. The rear shocks havebeen redesigned and now allow moretravel and more damping. A longer strokeallows 3.8 inches of wheel travel, a halfinch more than before. Compression

damping has been increased from 25 kilo-grams per meter per second on the K5to 30 kg/m/s on the F. Rebound dampinghas gone up from 100 to !20 kg/m/s.

The ignition lock has been moved upbetween the instruments, and it will alsolock the fork when turned one notch pastthe normal "Off" position. This makes iteasy to lock the fork because you onlyhave to turn off the ignition to do so. Italso means that you can't forget to unlockit before starting the engine. The elec-trical system helps you to avoid forgettingother things as well. The standard Hondaelectric starter interlock won't let you startthe engine in gear unless the clutch isdisengaged, and a beeper reminds you toturn off the turn signals. And the head-light, taillight, and running light filamentsin the front turn signals come on auto-matically when the ignition is switched on.

There is a strange-looking box attachedto the left downtube in front of the enginethat contains the plug-in connectors pre-viously found in the headlight. We won-dered if you could hot-wire the bike herebut found the ignition leads arc routedelsewhere. The horn is loud enough forin-town situations, but a louder one isneeded for freeway use.

At 503 pounds with the gas tank dry.the whole package weighs two poundsmore than the K5 and costs between $2152(West Coast) and $2165 (East Coast).

ENGINE AND GEARBOX: When theengine is cold, you must lift the chokelever on the left side of the carb bankto its fully-closed position to start the bike.After letting it run a few seconds, you canlower the lever to a partial opening. Inless than a minute, the bike is ready to pullaway—although it takes at least five min-utes to lose its cold-blooded feeling andrespond to changes in throttle openingwithout behaving sluggishly.

With a lower overall gearing (highernumerically) in every gear, the CB750Super Sport gels away from a stop withless intentional clutch slippage than wasrequired on earlier model CB750s. It isalso capable of coming off the line harderand faster than its predecessors.

The lower gearing not only allows thebike to accelerate faster, but also to runat a higher rpm at the same speed in thesame gear. This is helpful because thelow-rpm throttle response is worse on theSuper Sport than it was on the K5. Despitethe lower gearing, some of the snap ismissing when you turn the throttle wideopen below 4000 rpm. Also, one of theinherent carburet ion difficulties found onall past 750s is amplified on the SuperSport. The CB750 we tested in Decemberstumbled and died when the throttle wassnapped wide open below 3000 rpm. Onthe Super Sport, the range in which theengine can't handle full throttle has beenextended up to between 3500 and 4000rpm. This flaw was particularly annoyingat the dragstrip. where we were trying toget away from a stop quickly. If we letthe revs drop below 4000 rpm while thethrottle was wide open, the engine wouldgo from full charge to full stop. Thatalmost threw the rider over the handlebarsuntil he closed the throttle part way . . .at which time it would leap ahead again.

The lower gearing helps to keep the revsabove the range where the throttle re-sponse lags. At 60 mph the Super Sport'sengine is turning a little more than 4000times per minute. The K5 model didn'thit 4000 rpm until about 72 mph. Oneby-product of the higher engine speed iseasier high-speed passing. It is rarely nec-essary to downshift when you are nippingpast a slower vehicle out on the highway.But if you do downshift, there is still morepunch in the Super Sport's third or fourthgear than there is in the same gear onthe old four-piper.

The power output of the 750 Four has

been raised from a maximum of 52.2 at8500 rpm on the K5 to 53.9 horsepowerat 8500 rpm on the Super Sport. Thepower increase combines with the loweroverall gear ratios to make the Super Sportquite a bit quicker at the dragstrip. It ranthrough the standing-start quarter-mile in13.10 seconds at 101.5 mph. The CB750K5 we tested in December of 1974 loggedquarter-mile figures of 13.65 seconds and98.6 mph. The performance increase wasobtained, however, in trade for a slightincrease in gas consumption. The HondaCB750 K5 averaged 42.6 miles per gallon,but the Super Sport got only 38.3 mpg.

In other respects the Super Sport's en-gine is much like a standard 750s. It willidle just about forever once warmed up.You can run it down to 1000 rpm in fifthand accelerate cleanly if you open thethrottle slowly and smoothly. There is verylittle flywheel effect, so if it's free of anyload, the Four will accelerate or drop toidle almost instantly. This quick-revving

characteristic made it difficult for someriders to shift smoothly because they hadtrouble synchronizing the engine speedwith the transmission speed.

Unlike the Honda CB400F Super Sport,which had its pegs moved rearwardslightly, the 750 Super Sport has its pegsmounted in the same position, with noexternal linkage added to the shift lever.And shifting requires the same deliberatefoot movement as with previous CB750s.A light or too-short shift will occasionallybring a false neutral or allow the trans-mission to pop out of gear. The gear ratiosare spaced fairly evenly, but there is abigger gap between first and second thanbetween any other consecutive pair ofcogs. Selecting first from neutral will elicita healthy clank from the gearbox, andthere are quieter clunks when the othergears are engaged. There is some trans-mission whine, a small amount of intakenoise, and a little primary chain noise. But\ou can hear them only because the ex-

haust is so quiet. The machine showedonly 78.6 decibels on our sound levelmeter.

A few fast take-offs early in the testglazed the clutch friction plates. Conse-quently it would frequently groan andgrab when engaged, especially if the en-gine was cold. Honda 750 clutches aren'tvery progressive anyway, and the grab-biness made it particularly difficult to use.Only the impressive low-end pullingpower of the engine made everything tol-erable when the clutch acted up whilegetting away from a stop in slow traffic.Clutch pull was light and we experiencedno dragging or unwanted slipping. Evenwhen it wasn't grabbing, the engagementspan of the clutch was very short, requir-ing a rather careful release to make asmooth start.

HANDLING: The CB750F doesn'thandle the way the numbers suggest itshould. With more rake and trail, and anaverage wheelbase of a little more than

58 inches. you would expect it to be aslow and heavy-handling machine. But theadditional rake and trail make the bikefeel significantly more stable and precisewhile cornering at all speeds. And theydon't make the steering feel heavy orclumsy, except at crawling speeds. Forexample, if you are trying to make a Li-turn in an alley with your feet on the pegs.the bike feels a bit more clumsy than theK5.

However, at higher speeds, the SuperSport's handling is much more stable,precise, and confidence-inspiring. Thetendency for the bike to fall inward whenthe throttle is closed slightly in a turn isgone. And. despite the fact the bike hasmore rake, more trail, more wheelbase. and

can be grounded during moderately hardcornering. Honda dropped the foldingright footpeg down so it will drag beforethe exhaust system, which is solid andcould lever a wheel off the road. The noiseand movement of the dragging peg warnyou that it is time to think about backingoff. With softer spring settings, the firstthing to drag after the peg will be the fatpart of the muffler. With stiffer springpreloads, you'll get the exhaust collector.The peg is probably the only thing thatwill drag on the left.

Although he sacrificed some corneringclearance by doing so. our lightest staffer(160 pounds) preferred the rear suspen-sion set on its softest spring preload settingand heavier staffers chose only slightly

ticularly over bumpy surfaces when thebars would twitch slightly. The demise ofthe rear shocks hurt the handling notice-ably, but the improved steering geome-try kept it from becoming unstable orunsteady. It was only slightly less pleasantduring hard, but sensible cornering.

The front suspension felt a little stifferthan the rear but it tried to smooth outall bumps, no matter how large or small.Only large, sharp bumps jolted the frontend hard enough to cause any concernfrom that quarter, and only during cor-nering. In all fairness, those same bumpswould have undoubted!) affected anyother machine we can think of.

The tires worked very well on all kindsof road surfaces, wet or dry. The Dunlop

more weight than the CB750 we lasttested, it feels lighter when you lean it intoa corner or steer it into a turn. Much ofthe top-heavy sensation has disappeared.It is a whole lot easier to make the bikestart turning, or change its direction orline while turning, or flick it from sideto side while negotiating an S bend. Italso takes and holds the line you havechosen better than the previous chassisdid.

There is a good deal more corneringclearance on the left side of the bike thanon the right. Unless you're very heavy orare earning a passenger and have theshocks backed off to minimum preload,the first things you'll ground on either sideare the "warning balls" on the footpegs.It isn't too difficult to do on the right,since the peg is about half an inch lowerthan on the left. It's this way because thecollector and muffler are out where they

stiffer settings. These softer-than-usualsuspension positions were preferred be-cause the bike tracked so well over bumps.and also because the resulting rearwardweight transfer provided the best handlingwhile exiting medium-speed turns (25 to50 mph) under power. This handling traitseemed to come partially from the weighttransferred onto the driving wheel, andpartially from the increased rake and trailobtained when the rear end squatted downunder power.

The rear shocks worked very well whenthey were new and added considerably tothe road-holding qualities of the big bike.Unfortunately, they didn't stay new forvery long. We noticed the rear suspensionfading slightly before we put 500 mileson the machine, and within a couple ofhundred additional miles, it became evenmore apparent. The loss of damping hurtthe bike's precision during cornering, par-

K87 at the rear is the best Japanese-maderoad tire we've come across. It's unusualto find a street bike with two differentbrands of rubber, but the Bridgestone ribcomplements the Dunlop quite well.

The added stability plugged into theCB750F's steering geometry keeps thebike stable when buffeted by crosswindsor gusts from passing trucks. The bike willgive off an occasional wiggle on rain-grooved road surfaces, but going down astraight road with both hands off the bars.it feels like it is on rails at any speed.

COMFORT AND RIDE: The only realcomfort difference between the K5 andthe Super Sport is a slight vibration in-crease in the latter. With the lower gearingand increased rpm. the vibration haspicked up a little—mostly in the handle-bars and very slightly in the footpegs. Thevibration is most pronounced when thebike is accelerating. The biggest annoy-

The rear brake has an excellent feeland progression, although weexperienced some rear wheel hop.The window at the top of thedouble-action caliper lets youmonitor puck wear.

ance created by the additional vibes isblurry mirror images, although riders whoarc conscious of it may be bothered bythe additional engine hum on long rides.Changing the countershaft sprocket and/or rear wheel sprocket will allow thetourer to drop the engine speed and vi-bration level back down to where it wason the CB750 K.5.

The handlebars have approximately thesame shape as those on recent modelCB750s. At 31.8 inches they arc fairlywide, and they're also moderately high.They offer a lot of leverage, which is nicein light turns or when maneuvering at slowspeeds, but their height and width spreadthe rider out in the wind at high speed.

The seat is comfortable for the riderbut less so for the passenger. The ridercan go for quite a few hours before fannyfatigue sets in, but the passenger's portionis harder and will make his bottom sorein about an hour. The rear part of theseat must be higher than the front to clearthe rear fender, yet contain enough foampadding to be acceptable for long distancetouring. With this problem in mind.Honda made a small step in the seat just

The new muffler looks differentthan most Honda mufflers andmakes the CB750 quieter than everbefore. Honda credits the 4-into-1design for some of the SuperSport's added power.

The headlight is smaller and lighterthan those on previous CB750sbecause much of the wiring hasbeen rerouted.

to the rear of the rider's section, then gavethe passenger's saddle a slight upwardslope. This way, the passenger has at leastminimal padding beneath him. and hedoesn't slide into the rider as much duringstops.

The pegs arc rather far apart for boththe rider and passenger-although thepassenger pegs aren't spread as widely ason the four-pipe models. We never foundthe width annoying or tiring.

The front suspension is just a tad stifffor maximum comfort. You never feeljolted or bounced by most road irregu-larities, but on a long ride your wristsbecome just a little tired from the mild

shaking they receive from small bumps.The rear suspension gave us an excellentride for the entire test, even when thedamping faded.

BRAKING: The front disc brake is thesame unit used on previous CB750s. Itrequires a lot of pressure to lock the frontwheel and is only moderately progressive.

The rear brake is very good. It's pro-gressive and sensitive enough to allow youto lock the wheel but not so sensitive thatyou can do it accidentally, even when down-shifting. There was a lot of chatteringand some wheel hop when the rear brakewas applied hard on bumpy surfaces. Thesame symptom appeared if the clutch wassnapped home in a lower gear during hardstopping with the rear brake. On smoothsurfaces, the rear brake was just fine.

Our best stops were in 141 feet 8 inchesfrom 60 mph and exactly 34 feet from30 mph. (The K5 slopped in 136 feet 3inches and 36 feel 4 inches.) The stop from60 mph was worse with the Super Sportbecause the rear wheel had a tendencyto step out to the left and get the bikesideways. To keep the bike straight andon its wheels, we had to back off thebrakes a little.

Neither brake faded at any lime duringthe test, at least when they were dry. Bothbrakes lost about 20 percent of theirstrength during their initial applicationwhen wet. although they returned to fullstrength almost immediately. They bothsqueaked when they got very hot and alsomade squealy noises for two or three daysafter the bike had been ridden in a rain-storm.

RELIABILITY DURING TEST: Theclutch provided us with the biggest prob-lem we had with the Super Sport. Earlyin the test, we made some fast starts with

Most of the plug-in connectorsformerly found in the headlight shellare now housed in this plastic boxon the left front downtube.

the revs up and the clutch slipping. Thisoverheated the friction plates, causing theclutch to grab badly and groan loudlywhen it was engaged. The fix prescribedby Honda was new clutch friction plates.There are seven plates, and each one re-tails for between $2.61 and $3.50. Thoseprices, incidentally, are for K5 plates. TheCB750F has new style plates, preciselydesigned to remove the problem we en-countered. At the time, there was no priceestablished for them.

The speedometer on our bike also wentSouth right after we received the machine.The needle wiggled around a lot and itread about 20 mph too fast much of thetime. Since Honda instruments are notrebuildable. you would either have to livewith it or replace it. The price of a newone ranged from S43.90 to $46.31 at theshops we checked.

A thousand miles or so of moderate useleft some deposits on the plugs, so we hadto replace them before getting a strongrun at the dragstrip.

The bike required one chain adjustmentevery 500 to 900 miles, depending on how-it was ridden. The disc at the rear removesentirely the need for brake adjustment.The dry-sump lubrication system neverrequired the addition of any oil. and thebike never needed any attention exceptchain lubrication.

SUMMARY AND CONCLUSION:The changes Honda made to the CB750in creating the CB750F Super Sport havegiven it a new appearance, more powerand more punch, and a sound level thatis tower than ever. Some fuel economyand a small amount of bottom end powerhave been lost, however. The suspensionchanges have transformed the CB750 froman adequate handling machine into a re-ally good handling one. Only the short-lived rear shocks hurt the handling at all.The comfort level is still high, althoughthe vibration has increased just a little.We had several problems with our bike,ranging from a grabby clutch to an erraticspeedometer.

The CB750F is better than earlierCB750s for some riders and worse forothers. Providing the clutch problem iscleared up. commuters and in-town riderswill find the machine easier to ride intraffic than previous models because ofthe Super Sport's lower gearing. Perfor-mance-conscious riders will enjoy theadded power and acceleration which havebrought the machine back to the fringesof the superbike category, with the addedbenefit of improved handling. Honda-loving tourers may appreciate its abilityto pass more quickly in high gear, or theymay be put off by the added vibrationand fuel consumption- both of which canbe changed with the external gearing. Orthey may want to wait and see if Hondahas a shaft-driven, automatic-transmis-sioned 750 for them. Those who don't waitwill find the CB750F Super Sport to be abit more frivolous, but a lot more fun.