Motorcycle Sport 1973
Commuting 25 miles each day to and from the office in a car is frustrating in London's suburbs. With a change in office hours, the trek was due to become a marathon, so the decision really made itself—go back to two wheels after the relapse to four! After all, motorcycling is an active verb; of late there had been too much writing and not enough riding.
Two problems then asserted themselves. The first was clothing, which a trip to Comerfords soon sorted out in the form of a two-piece waxed-cotton suit. Keeping my feet warm and dry remains a problem due to the greatly lamented demise of the Dunlop overboots which were so unglamorous but so warm and easy to jump into and zip up. As they were, naturally, waterproof and sensitive enough to be used when racing in the wet, their loss is doubly mourned.
With clothing mainly sorted out, the second problem was which machine? It had to meet certain fundamental requirements. Capacity under 250cc, as the daily trek includes less than a mile of 70 limit and a couple at 40, so maneuverability and ability to sneak through gaps were more important than high-speed cruising. For the daily run, reliability and starting just had to be to car standards ... it had to keep going without trouble between services and it had to start first time, every time, in sun or a downpour. After due consideration of Suzuki, Yamaha, MZ, and so on, I made my decision. A Honda CD175 was chosen as being most suitable for my needs and as the most tractable and untemperamental regarding plugs, points, petrol, ignition timing and carburation.
The Honda was duly delivered. Externally, as you may know, it is very similar to the 250 (as tested by us last October). For one's £252 one receives a very well equipped and finished product that follows the now well established Honda pattern. Two colors are normally available, the deep plum red of the sample bought, and blue.
The engine follows Honda practice. It is a twin-cylinder with 52 x 41mm dimensions to give 174cc capacity. A single-overhead camshaft is driven by chain and operates the valves via rockers with adjusters at their ends, accessible by removing caps. Unlike some other engines, these caps do not fall off, neither do they have any complex locking. This happy state is achieved by the O-rings which also act as seals to keep the oil inside the valve chamber.
The CD175 has quite good looks apart from stylish SOHC. twin engine—little pretension to a sporting line 9 to 1 compression ratio and breathes through a single 22mm Keihin carburetor. Ignition is by coil and oil is carried in the engine sump; capacity is i gallon.
The gearbox is mounted in unit with the engine and is gear driven. Four speeds are provided, with the pedal on the left, splined for adjustment, and operating up for up. Starting is by foot as no electric starter is fitted. Unfortunately the kick-starter operates on to the gearbox, not the clutch, so that one has to be in neutral to start. Final drive is by chain and this is nearly fully enclosed, only the inboard side of the rear wheel sprocket is exposed. While this is a great improvement and does help to keep the chain clean, it is a pity that it is so near being fully enclosed but isn't.
The engine/gearbox unit is housed in a welded frame comprising both tubes and pressings. It is neat and the welding is good. Front suspension is by telescopic fork and the rear by pivoted fork. Unusual for these days, the rear-suspension springs are fully enclosed, as they should be, to keep dirt away from the damper rods. Deep, generous mudguards are fitted and the wheels carry 3.00 x 17in Ohtsu tires. Both brakes are single leading shoe.
Handlebar layout is standard Honda with alloy ball-ended levers for clutch and front brake, both having adjusters built in. The left-hand unit carries the flasher switch and horn button, and the right the lighting switch with positions for off, dip, park and main beam. A mirror is fitted to the right-hand bar and the left has provision for one, the tapped hole provided being neatly blanked off by a small moulded insert. The twist grip is one of those annoying axial things which operate by pulling the cable through the handlebars and the Honda version is like all the others, a little heavy, no friction control, excessive backlash and requiring far too much movement to obtain full throttle.
The headlamp shell also carries the speedometer which incorporates a milometer and warning lights for flashers, neutral and main beam. These are all of the correct degree of brightness and do not intrude at night. The headlamp itself can be adjusted for angle by means of a small screw at its base. Its beam is, however, something of a disappointment, lacking power. As no electric starter is used, the electrics are six volt, which may account for this. Flashers and rear lamp are, however, fully adequate and the stop lamp is very bright. This lamp is operated by either front or rear brake, the front brake switch being mounted in the lever on the handlebar very neatly indeed.
The electrics are controlled by an ignition switch mounted under the front of the petrol tank, with three positions. These are off, normal and park, the last position switching on the parking and rear lights only, regardless of the position of the light switch, and allowing the key to be removed also. The same key operates the steering lock and helmet holder lock, and four keys come with the machine, which should be sufficient unless one is very careless indeed.
The detail design of the Honda is very well carried out with small rubber bellows and sleeves over control cables to keep out the weather. Electric cables around the cylinder head are held in place by clips and, where necessary, are covered with a heat-resisting sheath. All earth return is by cable and a proper harness is used. Where it enters the ignition switch, it is heavily shrouded with rubber mouldings. At the control switches the wires are clamped down to prevent them being pulled away from the switch contacts and the control levers are prevented from rotating too far as this would cut the electric wires.
The whole is topped off by a 2.2 gallon tank, which is fully rubber mounted and equipped with knee pads so one does not wear the paint away. The tank is held in place by the dual seat so that removal of two bolts and the petrol pipe enable one to have complete access from above. Plastic side panels are fitted by means of moulded-in lugs pushing into rubber grommets in the frame. These panels are painted on the outside and cover the air cleaner and battery respectively. The main battery lead caries a fuse and three spares are provided.
Both a centre and prop stand come with the machine, the prop stand being a good firm example of the breed, which is just as well as the centre stand, although sturdy, requires considerable effort to use. A suitably placed grab handle would work wonders; as it is, one has to pull on the edge of the seat, and with an all up weight approaching 300 lb, the dry weight is quoted as 269 lb, getting the 175 up is not as easy as it should be.
A reasonable tool kit is provided and lives in a plastic bag on a small tray just above the pivoted-fork pivot. One suspects that in time the bag will split and the tools will vanish.
With the machine so well equipped and with the detail design well thought out, there is one surprising incongruity. This is the rear-brake pedal which not only has no adjustment for its position but clangs up against a frame cross-member which acts as a pedal stop. Tape and rubber stop the noise and protect the paint but it is an odd point for Honda.
As the machine was new the chore of running in had to be gone through. This passed uneventfully with the engine gradually being made to work harder and harder so that by the time 1,000 miles had been covered, the engine was being well revved as all Hondas seem to enjoy. The machine was still a little stiff but oil consumption had settled down to nil and all the controls were working nice and freely.
The performance proved to be fully up to expectations. The engine produces 17 bhp at 9,000 rpm, and 9,000 equals 26, 41, 55 and 70 in the gears, each of which speeds the machine attains. For town and suburban use the acceleration is quite adequate as one can reach a 40 limit in second and a 50 one in third. Second gear is particularly useful for passing traffic as one just stays in it as one accelerates past a line of cars doing 20-25 and the revs, keep on rising.
It is when one accelerates in third or top, or when one leaves the suburban speed limits behind, that one is quickly reminded that it is after all only a 175cc machine. Acceleration from 25 in third is naturally sluggish and above 55 one finds that the second half of the twist grip movement does not do very much at all. This, however, was what was expected and it is to the Honda's credit that in town one tends to forget that it is a 175 and look upon it as a 250 as'-one accelerates away from both the lights and the traffic. Out of town one holds 60 to 70 all the time without any bother.
At the other end of the scale, the engine is very tractable and no matter how hard it is driven it settles to a steady tick over when one stops. Part of the daily route involves walking the machine 50 yards to avoid a mile of riding and several hold-ups. Bottom gear, a closed throttle and the Honda rustles along at a normal walking pace every time without fail.
Although the need to be in neutral to kick-start is annoying, the actual starting is just as it should be. From cold one turns on fuel and ignition, fully operates the carburetor enrichment device, a lever on the left side and fully accessible at standstill and on the move, and kicks once. The engine fires and after a few seconds the lever is partially opened. Within half-a-mile it is fully open. For hot starting, a gentle prod is all that is necessary. The only times the machine has not started first kick hot or cold it has been the rider's fault for not prodding firmly enough.
While the engine is warming up, there is a slight tendency to stall due to a flat spot just above tick over. As the machine became run in, this has proved less troublesome, and anyway if one is moving forward at all, the clutch is dropped and the engine is running again.
Fuel consumption has now settled down to a steady 75 to the gallon of 4 star petrol. For convenience the practice has been adopted of purchasing 50p worth at a self-service station every time 100 miles is covered. This usually fills the tank from just off reserve to about three-quarter full and is both easy to remember while ensuring that one will not run out of petrol. Should one run on to reserve, the engine kindly gives due warning by slight misfiring but without completely dying, so that one turns on to reserve without stopping. This consumption may be worsened but it would be difficult to do this in town as the figure quoted above is the return given in hard driving with plenty of traffic hold-ups and consequent accelerations in the gears. No doubt three-figure consumption could be obtained by pottering but this rider does not potter, as he is usually late rather than early for the office. Incidentally, the self-service petrol station is advocated as one can determine when to stop pouring as it goes in, ensure that all the expensive fuel finishes inside the tank and not outside it, and avoid damage to the tank finish from carelessly handled pump nozzles.
With any small-capacity, high-revving engine the gearbox has to be used and the Honda is no exception. To keep moving briskly, one is up and down the gears continuously as dictated by traffic conditions. The engine is tractable enough to pull from around 20 mph in top gear but acceleration is mild, to say the least. From that sort of speed, one drops two gears if in a hurry. Unfortunately, in view of the amount of gear-changing done, both due to traffic and engine characteristics, the Honda gear-change is adequate rather than good. When changing up there is a tendency to clunk and for the transmission to snatch slightly. This is not a major fault but something that is hard to detect although one is always conscious that it is not one of the best. It is when changing down that the mechanism becomes annoying, just as the 250 was when tested. This is, apparently, a common Honda characteristic which manifests itself by the box changing down from top to third and then steadfastly refusing to go down to second. Moving the gear pedal does not result in a neutral being found, the thing just stays in third. This becomes something of an embarrassment if one is stopping as the engine just will not pull away in third, even second is a struggle, so one has to juggle with the pedal until one finds a lower gear.
As the gearbox ran in, this problem became less of a nuisance and appears to occur because the gear-change does not match the engine. Thus the change is inherently a slow one requiring full and complete pedal movement. The engine, however, is a high-revving unit with light flywheels and low rotational inertia, for which a fast change is needed. The practical answer to the problem is to change down early while the engine revs are high, the engine seems quite unworried by a change down pushing its speed up to peak rpm and to change on a rising throttle opening. Using these techniques, I found, the gear-change improved greatly and became fast and always positive.
The actual gear ratios are well suited to the engine performance so that at no time in any gear does the machine feel over or under geared. Clutch action is light and the take-up smooth and progressive. The clutch always frees first thing in the morning. When one is riding the bike, the clutch free play increases slightly when the engine is warmed up and reverts to its original condition as the engine cools off. This occurs when driving gently or after a series of near full throttle starts, all of which the clutch takes in its stride without a murmur. The full engine performance can be indulged in without becoming too anti-social as the twin silencers do a reasonable job of quietening the exhaust noise. Naturally there is a fair degree of engine noise at high revs, more of a howl than any particular rattle, but this is of an acceptable level. In top gear in town, or even when accelerating fairly briskly, the machine is commendably quiet. In view of this it is fortunate that the horn is loud. Not perhaps as strident as one could desire for motorway use, but quite adequate in town. The horn button could not be better placed, falling naturally to the left thumb when required. Just above the button is the flasher switch and this too is placed just right with sufficient feel in it for operation by a heavily gloved hand. No problems with overcorrection have arisen with this.
Unfortunately the same cannot be said about the light switch. As the right hand is well occupied in operating the throttle and front brake by what is in the main a rotary action on the handlebar, the axial movement of the switch is awkward. Selection of main beam is not too bad as the switch is moved fully over, but when returning to the dipped beam position it is all too easy either to stop halfway on the parking position or to switch the lights right out. Neither of these actions has much to commend it.
It is curious that in a car this form of switch incorporating all functions is desirable but seldom used. On four wheels, one would like side, dip, main and flash all on one lever so that one could go from side to dip quickly but without dazzling other drivers by using the flash position, or fumbling for a switch on the dash which has become even more awkward to use in a hurry now that the makers are all safety conscious and rockers are employed instead of the older type of flick.
Conversely, on a motorcycle one always wants to ride with the headlamp on at night as the parking light is far too easily missed by other traffic and pedestrians. Thus it is desirable that the lights are switched on by a separate switch - the ignition one would do and beam selection only be carried out by the handlebar control. This would allow the use of a built-in two-position switch on the right bar which would be more natural to operate and could select in the correct sense, i.e., up for main beam.
The brakes on the Honda, although both are single leading shoe, are quite adequate for the speed and weight of the machine. The extra weight of a passenger does not worry them either. The front one is nicely progressive without any tendency to snatch or grab; one just squeezes the lever harder if one wants to stop faster. The rear feels rather dead and needs a firm foot to obtain retardation. Due to this, it has no tendency to lock up even in greasy conditions. In town there is little likelihood of brake fade occurring anyway but although the brakes have not been pushed to the limit there is no indication at all that fade will occur.
Road holding, steering and comfort tend to be personal matters with any machine. The Honda, like many other Japanese machines, is let down in the road holding department by its tires. In the wet and windy conditions prevailing during December, and over slimy, greasy and muddy road surfaces near some local road works, the machine was not as happy as it should have been. In the dry it handles well enough whether the road is smooth or bumpy but in the wet the lack of grip starts to show. Fortunately there is nothing vicious about this and if the tires are near their limit, the machine just edges sideways slightly. A change to Dunlop’s is reputed to improve matters no end.
Road holding is upset by high winds too. The first realisation of this occurred when accelerating away from some traffic lights. Circumstances were against the Honda as the change into second coincided with an abrupt change in road gradient and the wind coming round the edge of a tall building. The result was the front wheel stepping sideways about 6in! With the gales experienced in December, the Honda became just a little too exciting to ride as it reacted badly in cross winds, particularly on wet roads. Again the tires did not help, but neither apparently did the mass of side area the front wheel and mudguard presented. It is possible that the areas in front of and behind the steering axis were the wrong way round as the wind appeared to try to turn the bars the wrong way for correcting the effects of the gust on the machine in general.
The Honda's steering is good and completely neutral in that one points it where one wants to go and that is that. This is as one expects from a 70 mph machine and must be helped by the relatively stiff suspension. Front fork movement is 4in and at the rear only 2iin is provided so one would be surprised if the steering was other than excellent.
Comfort is adequate but not luxurious. The layout of seat, footrests and handlebars is very satisfactory but the seat is only moderately thick and the hard suspension passes the larger bumps on to the rider. In addition, there is the well-known vertical twin vibration. This Honda has a 360 degree crank so vibration is present and can be felt as a tingle at the bars and through the seat when high revs are used. This only occurs when the engine is turning over at 7,000 and above so it is not noticed in normal town driving.
This vibration is no doubt the cause of the two failures the Honda has suffered. The first occurred at 1,100 miles when both parking and tail lamps ceased to operate. The first was the filament and the second due to the earth lead coming adrift from the rear-lamp assembly. With these items rectified the Honda motored on to 1,500 miles when the dip filament blew, so another new bulb was needed.
The only other problems with the Honda have been more service ones than reliability faults. The first concerns the need to heavily grease the twist grip mechanism to lighten the throttle action and the second, also cured with grease, being the steering lock which became stiff after three months' use.
Servicing the Honda is straightforward, normal servicing occurring at 3,000-mile intervals but with oil changes every 1,000 miles. This is a very easy operation to carry out as the sump can be drained into a tray as a car. A 19mm spanner fits the sump plug, although a fin AF, being 19.05mm, is perfectly usable but it must be a good fit on the plug. A word of warning, the plug must not be over tightened. It carries an O-ring acting as an oil seal and the normal procedure of tightening with fingers, then spanner and then the final nip with the spanner results in the plug becoming nearly immovable next time round. The secret is to omit the final nip and all will be well. Lean on the plug however and you may shear it in half when next you try to undo it.
A further warning concerns the engine screws. These are a fairly soft steel and are done up really tight in Japan. Standard trade technique is to use an impact driver and this is virtually essential. Not included in the service schedule but worth checking are the exhaust ring nuts which can work loose and draining the float chamber by the screw thoughtfully provided.
The remainder of the servicing is straightforward and easily and quickly carried out, provided that one takes care not to damage any of the many oil seal rings used in the engine. One essential is to refit the offside crankcase side cover correctly as its three screws are equispaced. This cover has internal drillings which are an essential part of the lubrication system and one could fit the cover incorrectly, with dire results.
When the choice of machine to purchase was being made, the two Hondas nearest to the CD175 in price were also considered. The first of these, the Honda CB125SS, was £45 cheaper and the test carried out in September last year showed it to be a good 125. However, this rider prefers a little more capacity for town acceleration and to his eyes the 175 looks much more motorcycle than the 125,
The other alternative is the sports version of the machine purchased, the CB175, which costs an extra £47. When comparing the CB with the CD it is surprising how many changes have been made. It is not a minor uprating plus a paint job. The basic engine is the same but has twin 20mm carburetors to enable it to add three more horsepower and another 1,000 rpm to its scale. Electric starter and 12-volt electrics are also featured and the unit carries a five-speed gearbox. As the tire size is also changed to 2.75 x 18in front and 3.00 x 18in rear, the drive sprockets are different, with the result that peak rpm in gears one to four give the same speeds as the CD, with fifth geared for 80.
The same frame appears to be used together with the same basic front fork but at the rear a little more movement is provided and the damper springs are exposed. A twin-leading-shoe front brake is provided, possibly partly because the dry weight is increased by 3lib.
The decor is changed with a different tank, no knee grips however, and a ribbed seat. Mudguards are more skimpy, and chromed, and the side panels a little changed. A rev-counter is added to match the separate speedometer so a different headlamp shell is used, also the controls have the starter switch added and a left-hand mirror is provided although they are of a different type from that fitted to the CD. The remainder of the equipment is the same, except that no prop stand appears to be provided although its rubber stop is still fitted to the nearside silencer.
Is the CB version worth the extra money? In terms of value for money both machines are excellent, so the answer to the question depends on the use to which they will be put. If one was doing much out-of-town riding the CB could be the better bet. For this scribe it certainly would have been today as a round trip of 150 miles on business had to be made. However, tomorrow and the next day the CD is preferred as these round trips are fairly rare while the commuting happens five times a week.
So within the terms set out originally, the CD175 has amply fulfilled itself. It starts first kick, has not missed a beat and deals very well indeed with heavy traffic. It is excellent value for money, well designed, well made and well finished.
For the commuter who requires a fully equipped machine giving brisk performance with reliability, the CD175 has much to offer.