Visually, at least, a Harris Magnum takes a bit of getting used to. The frame dominates the proceedings, intertwined around the engine like a pair of newfound lovers. The act is indeed an intimate one with those sturdy frame tubes passing within millimetres of the engine, holding on to every movement of the cycle parts and power plant with a grip verging on overkill. The result is precision seldom seen in production motorcycles that have to pamper many whims and needs. The Magnum has a single purpose, to carve a line into a series of corners, take it or leave it.
The brazed Reynolds 531 chrome-moly tubing used in the construction of the frame provides a healthy compromise between immense strength and light weight making what looks like a heavier piece of metal than the standard Honda item far less so. The design of the Magnum frame sees the lower frame rails replaced completely by a gathering or tubing around the outside of the power plant. No frame tubes pass over, or indeed under, the engine which also acts as a stressed member, and yet the finished result is immensely strong. The complex array of tubes creates a structure with strength far in excess of the traditional twin loop cradle that the engine sat in at the start of its life. The endurance racing roots are immediately uncovered here as this open loop design enables the fast removal of a complete engine, mid race should a major blow up occur.
At first the extreme, racing rear-set seating position does take some adjusting to, your feet are way up behind you and all of your body weight is balancing somewhere just behind the wrist. Getting the first leg up and on to the high footrest at a standstill is hard enough, adding a second while on the move is near on impossible. This makes slow speed manoeuvring look clumsy for the first few meters as every input, be it intentional or otherwise, yield huge movements from the responsive steering. It’s a case of relaxing and enjoying the ride, which, once this has been achieved, becomes little different to a conventional machine. The slightest thought of a change in direction has the lively Harris begging to be let loose, this willingness gets keener by the bucket load the further around the dial that the speedo needle goes. Going faster gets a quicker response all around the bike, it’s as if the chassis has a serious drug habit and it’s the kind that will only add points on to your licence. Compared to the donor machine the weight felt through the bars is noticeable by its absence. Even with the narrower bars required to match the image, the Magnum can be moved around with ease once a few knots have been built up. 40 kilos have disappeared off the menu, leaving an addictive plate full of power and little mass to hold it back, party on.
Adding to that party is a raucous, rock and roll soundtrack provided by the open, Harris designed and fabricated, exhaust system. It’s a total attack on the senses, the eyes can’t believe what they are seeing while the ears can’t take in the noises and somewhere deep inside your helmet the brain is trying to make sense of the whole lot and turn it into some form of useful information. On most occasions the bike is a few steps ahead of your own thinking and appears to be tipping into corners with stunning accuracy all by its self. The slightest wisp of throttle mid corner onwards has the sharp end heading on out and accelerating hard, the rear suspension getting tauter as the engine digs in, keeping the front wheel planted firmly on the tarmac.
It doesn’t get much better than this, a stonking engine wrapped up in a state of the art chassis. The Harris brothers, Steve and Lester, really know their stuff when it comes to harnessing power and getting it to behave on the tarmac. Miles of top level endurance racing in the mid 70’s, where the demands placed upon both chassis and engines are never higher, have resulted in their cumulative knowledge being put to great use on the roads.
The inline four power plant is placed an inch or so higher in the frame than the Honda version of the CB900F, this is against the usual thinking of racer type design but providing not much else is placed up top it doesn’t make a lot of difference and creates far more ground clearance. Even with the engine up on high the Magnum is still a more manoeuvrable machine than the original CB, especially at high speed. To be fair though the two machines are destined for all together different tasks in life and it would be hard to imagine anyone commuting to work or doing huge distances touring on a Magnum. The rear seat hump is detachable revealing a pillion seat, albeit it unfeasibly small, upon which, no doubt, many a jean clad girl has hung on. Don’t be fooled into thinking the pillion seat is of any practical use however, the single seat option is the only way to go both for handling and style no to mention credibility. With any machine wit a serious race track heritage the rider will be placed over or very near the rear wheels axle, any further weight in this area unloads the front end with undesirable results.
The race bred chassis works very well on the road. With the exception of the restricted lock stops making U turns fraught with danger, the rest of the tube work handles the bumps and potholes of the open road with ease. Stiff usually means a few out of the seat moments on all but the smoothest of race tracks but somehow the combination of Marzocchi forks and White power rear shock team up to make the ride accurate and yet also compliant with the tough demands of the open road. It isn’t easy getting a race bred machine to work on the road, many have tried but few have succeeded. By carefully designing, or selecting each component used in the Magnums construction, this balancing act can be carried off convincingly, as is the case with the Harris Magnum.
The Magnum could be bought either as a complete bike, or more likely as a series of parts into which you would put the bits of your on machine that you wanted to keep. If the complete package was opted for then you would be riding on state of the art Marzocchi forks and White Power suspension. Brakes would be either Lockheed or Brembo twin-opposed-piston racing callipers grabbing on Brembo iron discs with stunning effect. Because of the nature of the whole Magnum ethos the engines providing the necessary go for the beast would be the most powerful of the day.
Harris performance products still make components for the old style Magnums upon request, making it one of the few ways you could get a brand new 80’s machine.
Although now in its 4th generation the Magnum is still very much alive and prospering with frame kits still listed by Harris on their website. They still produce frame kits for the following;
Magnum 2
- GSX1100EFE
- GSX-R750 oil cooled
- GSX-R1100 oil cooled
- Bandit 1200
Magnum 4
- GSX-R750 oil cooled
- GSX-R1100 oil cooled
- Bandit 1200
Magnum 5
- Fireblade pre 2000
- GSX-R100 water cooled
Harris, the company and the Magnum Dynasty
As a company Harris are as famous as any within the motorcycle world. They have built many successful machines over the last 34 years including GP machines for the likes of Barry Sheene and the Yamaha factory team as well as producing complete road going bikes and countless products to make your machine do what ever it is you wish it to, but better.
The Harris brothers began their working lives building racing cars albeit for different companies. Racecars of the day were largely tubular in construction and this gave them the knowledge they needed to modify motorcycles, an area of great interest as they had both taken up club racing with some success. In 1972 the pair decided to create Harris performance products to enable their work with motorcycles to continue on a full time basis. Within four years they had made an impressive mark upon the racing world. Harris modified the poor handling Yamaha TZ750 to such good effect that for the start of the first race of the 1976 European championship held at Silverstone, 18 of the 32 starters were using Harris machinery.
The original Harris Magnum was a road-legal version of Steve and Lester Harris’s Z1000-engined race bike of the late ’70s. “The first bikes were just endurance racers on the road but then we made a proper road bike, the first Magnum, with a road fairing and fibreglass tank cover,” recalls Lester. “A 1981 restyle by Target Design (creators of Suzuki’s Katana) produced the Magnum 2, generally powered by Suzuki’s GSX1100. That was by far the most popular Magnum.
We’ve probably sold about 800 and still get the odd order even now. The mid-’80s Magnum 3, initially for Kawasaki’s GPz1100, had a frame made from a mix of steel tube and aluminium plate, plus rising-rate suspension, 16-inch wheels and radical geometry compared to Japanese roadsters. It handled really well but wasn’t great to look at, and never sold particularly well,” says Lester. “We remembered that lesson when we built a bike for Suzuki’s GSX-R motors a few years ago. The Magnum 4 had a steel frame with the geometry of our alloy-framed endurance racer, and we made sure it was styled right too.”
Harris Magnum CB900F Specifications
- Engine – air-cooled, four-cylinder, four-stroke, dohc
- Capacity – 901cc
- Bore & stroke – 64.5x69mm
- Compression Ratio – 8.8:1
- Carburetion – 32mm keihin CV
- Max Power – 95bhp@9000rpm
- Torque – 56ft-lb @ 8000rpm
- Ignition – Honda CDI
- Transmission – five speed chain final drive
- Frame – Harris Magnum 2
- Suspension – 38mm Marzocchi forks, single White Power rear monoshock direct link
- Wheels – 110/80 x 18 130/80 x 18
- Brakes – Lockheed twin opposed piston calipers 265mm cast iron discs, single Lockheed twin opposed clipper 265mm cast iron disc
- Wheelbase – 1435mm (1500mm CB900F)
- Weight – 192kgs (233kgs CB900F)
- Fuel capacity – 19 litres
Harris Magnum II CB900F Gallery
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