Kawasaki KR250 – Ultra Rare Tandem Twin Two Stroke

For reasons I cannot fathom, the Kawasaki KR250 race replica was never released here in the UK. Nor did it make an appearance in North America, or mainland Europe.

This makes the KR250 one of the rarest two stroke racing rep bikes from the 80’s and ironically, one of the cheapest – if you can find one for sale!

Read on to learn more about this fascinating quarter litre pocket rocket.

Kawasaki KR250 Review

The story of the Kawasaki KR250 goes all the way back to 1965 and Kawasaki’s foray into road-racing with a 125cc water-cooled twin, so let’s have a brief history recap. 

At the time air-cooled machines were prominent but it was just a few years later in 1969 when Dave Simmonds won the 125cc World Championship, having been experimenting for the prior 4 years with water-cooled bikes.

Simmonds went on to campaign for the AR-1 and A7-R (250 and 350) air-cooled twins. The bigger H1 500 and H2 750 soon made an appearance as air-cooled triples and culminated in the KR750 which was a water-cooled triple raced by riders such as Gary Nixon and Mick Grant. 

In essence the success of these prior machines led Kawasaki to utilise the same technology in developing a 250 and 350 in order to compete in the relative GP race classes. 

The collaboration of this new racing programme was between Kawasaki’s base in Japan and the US research and development centre and it really got started in 1973. 

The KR750 was at the forefront of the development process with the KR250 being kept a secret but both were intended to be ready for the 1975 race season. 

Ken Yoshida who was lead engineer of the Kawasaki racing group at the time had been given the KR250 as his main project and he was under strict time constraints to make it happen.

It was a time when the world market was opening up for Kawasaki and there was a gap for them to compete with Yamaha in the realm of 250cc bikes, in both the FIM World Championships and AMA lightweight class. 

They were keen to build on the racing story Simmonds had started to piece together on his 125cc, time was really of the essence, especially as motorcycle technology at the time was rapidly changing.

Fortunately Kawasaki’s 250 project headed by Yoshida would be a success and the KR250 was brought to the world stage, taking a total of eight world championship titles (along with the KR350).

In 1982 the UK restricted learners to 125cc essentially outlawing 250’s as learner bikes and limiting the market. While the Kawasaki KR250 never actually made it to the UK anyway, any chance of it being produced for the UK was subsequently knocked on the head. 

All efforts turned to bigger capacity machines both on the road and track.

That’s it for your history lesson, let’s see if it is any good. 

The KR250 Engine

Nagato Sato, a young engineer, had sat down with Ken Yoshida and by 1973 created a newly designed engine unit. It was a tandem twin that had two separate cranks, geared together with one ahead of the other.

The inline layout minimised the width, while disc valves could still be utilised. The rotary valves and carbs sat on the left while the ignition and primary drive sat on the right. 

Yoshida and Sato worked together to ensure the engine was high performing, reliable and efficient. While the design is often credited to Yoshida it was Sato who did the detailed drawings for production.

A normal across the frame twin with a crankcase induction engine would be too wide. It would be too difficult to ensure efficient airflow to the carbs while optimising the handling and reducing the frontal area. 

Instead offset crankshafts meant that the rotary valves could be overlapped and the overall length of the unit could be shortened. 

The crankcases and rotary valves were cast in magnesium to keep the engine weight down, but this later was changed out to aluminium as it performed better and was more durable.

Water-cooling was essential to maximise performance. 

At first the engine had a 180 degree firing order that caused heavy vibrations, this was problematic. It would vibrate so ferociously that it would break the front exhaust pipes that was until a spring-joint was fitted in the weak point in the pipe. 

Sometimes it would cause problems with the check valve in the front brake master cylinder which meant that the rider would pull on the brake lever for it to have no effect. 

The vibration problem was soon resolved by changing the firing order to 360 degrees which meant that both pistons would move up and down and fire together. 

Initially the KR250 had been built to have a 6-speed gearbox as required by FIM rules, however, the model wasn’t required by AMA rules to be restricted to a 6-speed. 

So for American models the KR250 had an adapted gearbox with a 7th gear which allowed for a greater range more suitable for the US race circuits. 

The design of the gearbox was too far along to make a cassette type changeable gearbox, so the 6-speed casing was adapted so a special plug could be screwed into the bottom and fit into a shift drum groove essentially locking out the seventh gear for FIM regulated races.

The end result was an advanced, capable engine that Kawasaki were proud of and stored a lot of faith in. 

Vibration was minimal and the whole experience was a smooth ride. 

It wasn’t without its issues as it ran hot. Too hot for optimal performance on the track however, this would be addressed as the racing season progressed. 

Some components needed to be swapped out for heavier parts as the lightweight components weren’t up to standard in terms of durability. 

It was a learning curve but as production continued and more races took place, Kawasaki further refined the design. 

How Did The KR250 Handle?

The emphasis throughout the whole design process was to keep the bike as lightweight as possible. This didn’t just apply to the engine but to the motorcycle as a whole. 

Both brake discs were aluminium with a sprayed steel coating.

The single front brake caliper was cast into the aluminium fork sliders for the first part of the 1975 season. However, as the bike got faster a more conventional braking system was needed and applied with stronger calipers and bigger discs. 

Brakes were perfectly set up for the ride and were powerful enough to stop the bike and slow down before hammering the throttle out of a bend. 

Morris Mag wheels and Koni suspension setups were used as they were on the bigger KR750. 

The frame was a twin-loop steel tube, and eventually would receive long-travel suspension and an aluminium swingarm which was the newest innovation of the time. 

Cycle World states “The story is told that the chassis was at a point referred to Kawasaki Heavy Industry’s bridge-building division for their suggestions on stiffening it. It came back with a welded-in diagonal member passing through the space normally occupied by the engine!”

The overall finished product was an incredibly lightweight machine that could be built to under 100kg. 

The bike handled very well, being in such a lightweight chassis the engine was more than powerful enough to deliver brilliant performance on the track. 

The underslung shock, anti-dive forks were adjustable to suit the rider and terrain so you could really dial in the ride.

Agile, precise, nimble are just some of the words journalists used at the time to describe the KR250, which all make for a confidence boosting bike in fast corners. 

The fit and finish of the Kawasaki KR250 was at the time generally considered to be excellent and above the standards of other similar machines such as the RG250 from Suzuki. 

Comfort wise the Kawasaki KR250 also took the win over the RG, the overall ride quality was more refined and palatable on regular roads not just the track. 

The seat was of a thick dense foam and bars relatively high which made for a sporty but relaxed riding position.

Kawasaki KR250 Race Wins

Of course where the Kawasaki KR250 came to life was racing on the track, and that was the whole purpose of its existence. The following are just some of the notable race wins for the KR250:

• 1977 – First at the Dutch TT, Arlen Race Circuit
• 1977 – First at Laguna Seca, Gregg Hansford at the helm
• 1977 – First in the Lightweight Class, Mosport Circuit, Canada, Yvon Duhamel
• 1978 – First at the Daytona 200, Gregg Hansford
• 1978 and 1979 – First in the Grand Prix World Championships with Kork Ballington
• 1980 and 1981 – First in the Grand Prix World Championships with Anton Mang

Kawasaki KR250 Spec’s

Engine and Transmission

• Engine – Tandem twin cylinder, two-stroke
• Capacity – 247cc
• Bore x Stroke – 54 x 54.4mm
• 34mm Mikuni Carb
• Transmission – 6-Speed
• Clutch – Dry
• Final Drive – Chain
• Max Power – 56 horsepower at 12,000rpm
• Max Torque – 47.45Nm at 10,000rpm

Chassis and Dimensions 

• Frame – Steel tube, double-cradle
• Front Suspension – 36mm telescopic forks
• Rear Suspension – Koni shock
• Front Brakes – 310mm disc
• Rear Brakes – 210mm disc
• Weight – 104kg
• Wheelbase – 1360mm

Kawasaki KR250 Top speed

While the KR250 track bike was said to be able to reach 155mph, the road version did 112mph before any tinkering.

Finding a Kawasaki KR250 For Sale

The Kawasaki KR250 was actually only ever sold officially to Australia, South Africa and Japan. Some imports made it across the seas to the States and the UK but these were few and far between. 

MCN states that “Those in the know reckon there are less than 50 in the UK, 30 of those arriving in a batch independently imported by Huddersfield Kawasaki.”

Despite the above, current US and UK market prices aren’t too bad. Perhaps the Kawasaki KR250 slipped off the radar of riders at the time and it is a little known gem that people haven’t quite cottoned on to yet. 

Whatever the reason it is great for those in the know that are looking for a late 70’s/80’s racing two-stroke 250cc to have an absolute blast on. 

The only issue and it is a pretty major one that affects riders on both sides of the pond, is that finding a Kawasaki KR250 is a real struggle. 

So while they may not be as costly as other motorcycles from the era, they are certainly more tricky to find. 

In the UK prices seem to sit at around the £6,000 price point. 

In the US I have seen adverts dating back to 2016 with prices ranging from $1,500-$4,000.

The key when searching for a Kawasaki KR250 is going to be finding one in good condition, that hasn’t been obliterated by an amateur mechanic, racer or both. 

Slipping under the radar has meant the KR250 hasn’t necessarily been treated well or with the respect it arguably deserves, so finding a good one will be an even harder task than finding one in the first place. 

Verdict

So while there may be few KR250’s in the US or UK today, the bikes are well worth getting hold of if you can. They hold a substantial place in Kawasaki’s racing history and took a lot of development to get right. 

It was a true labour of love for those involved from the designers to race teams across the world who were heavily involved in the bikes development. 

Hard work pays off and the Kawasaki KR250 took a lot of hard work. Now, how do I go about finding myself one?

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