The Fastest 250cc Motorcycles

The 250cc sector was a battleground of the motorcycle industry for many years. Manufacturers pushed the boundaries to create the best and fastest 250cc motorcycle they could. 100mph was a threshold some thought would never be broken, but it was smashed in the end.

Apart from a few exceptions I mention that were small batch hand made bikes not actually included in the main list, these are Production bikes. Even if some are exceptionally rare.

This is a tale of the bikes that led up to and then ran away with the prize for the ultimate ton up 250. It’s a list that works best done in date order, then you will see the year on year battles to win the title of fastest 250.

Don’t forget, there are timestamps to help you find where you left off if you have to watch it in two parts. It just didnt seem right splitting this one up.

As usual there are some curved balls, and some more unusual entries, as well as the bikes you might well remember riding. So buckle up, This is going to be an exciting journey into the battle for speed and into the minds of the people who built these unbelievable machines.

Remember, the Japanese market liked 250cc motorcycles, and often kept the best for themselves, So some of these bikes only hit our shores because a few grey imports squeezed their way in. Others arrived here a year or two after their first release in Japan.

Some of these fantastic machines were meant for tuning too, but here I am going to stick to the figures for the standard bikes as much as possible and I have tried to only use verified speed data.

Todays Crop

To put things into perspective, first I want to look at today’s 250cc motorcycles as a comparison. The Husqvarna Svartpilen and KTM Duke 250 both produce around 30HP and will reach speeds of around 91mph or 148 kph. Then there is the 2018 ninja 250R SE, a more highly tuned version of the standard Ninja that will make 39HP. It weighs in at 163Kg dry and will reach a top speed of around 105mph.That is the fastest modern 250cc motorcycle available.

As we go through the list I want you to keep those figures in mind and we will discuss them more at the end.

One last thing to try put into perspective are some bikes that were made very much earlier than you might think, that had performance levels that would still rival the best today. No, they aren’t the complete package some of the more modern bikes would be. They were effectively production race bikes, so cant be compared as equals, but they do need to be mentioned.

The Cream Of The Past

Looking at the cream of the past we have the 1957 Mondial 250 Bialbero. It produced 35 HP at 10,800 rpm and had an unbelievable top speed of 135mph. The bike, which had gear driven cams went on to win the 1957 250cc title in the hands of Ceyl Sandford.

Then there is a motorcycle that became one of the most sought after designs of its day, eventually leading to Harley Davidson buying the company in 1972. However, it was 1961 when the Aermacchi Ala d’Oro was released as a production motorcycle.

The engine produced a relatively unremarkable 24HP in standard trim but it weighed just 123kg and had a top speed of over 105mph. In race trim by 1981 it had reached an incredible level of tuning and was clocked at over 130mph. So in actual fact all the bikes that came after were really trying to chase a prize that had already been won.

The Ala d’Oro would be the fastest production motorcycle for the next 22 years, but there are some important motorcycles that tried to take its title away over the intervening years and they do need to be discussed.

A Special Mention For MZ

I also have to give a mention here to MZ and Walter Kaaden. They pioneered the use of Rotary induction valves and expansion chamber exhaust design, making two-strokes faster and more powerful. Without them many of the bikes that came later may never have existed.

MZ had been developing their two stroke technology since 1960 and despite the defection of their star rider, Ernst Degner, with the technology he stole, their design efforts continued. By 1970 the 250cc water cooled engine was producing over 60 HP at around 11500rpm.

The bike had a maximum speed of over 150mph. They just didn’t have any riders capable of producing consistent results.

So, now we get to the list properly.

I will begin in 1960.

Honda CB 72 Dream Twin

The Honda CB 72 or Dream Twin as it became known, was the first Honda and indeed the first Japanese motorcycle to be offered in Europe and the UK. The Overhead camshaft twin cylinder engine with twin carbs produced around 24HP at 9000 rpm and the bike weighed just 153 Kg dry. It had a 99mph claimed top speed and regularly tested around the 96 to 98mph mark in various real world conditions. It was built from 1960 to 1962 and would become the benchmark for 250cc performance on a standard road going motorcycle.

It didn’t have the racing pedigree of the Bialbero or Ala d’Oro, but it didn’t have their price tag either. It came in at a list price of just £293 in 1962 which actually worked out at around 20 weeks wages for the average UK worker at the time.

Ducati 250 Mach 1

Next in 1964 we had the Ducati 250 Mach 1. This motorcycle was produced in very small numbers with only around 800 ever being made. They were only manufactured over a 3-year period between 1964 and 1966. The Mach 1 was advertised as the fastest 250 anyone could buy in the 1960’s, and although we know already it wasn’t, It is still considered today as one of the finest motorcycles ever to come out of the Borgo Panigale factory.

The sad news is that with many destroyed on racetracks around the world, an original 250 Mach 1 is now a very rare bike.

Kawasaki A1 Samurai

Next we come to 1967. Kawasaki release the first A1 Samurai. This rotary disc valve vertical twin was the forerunner to the next generation of 3 cylinder 2 stroke Kawasaki’s that followed. It produced 31HP and weighed around 150kg dry.

This is another motorcycle the factory claimed 100mph for and with tuning it would go beyond that, but the best confirmed test I could find gave it a top speed of 93mph standard, although the conditions weren’t great. Suffice to say that its place on the list was secured because without it we may never have had the later triples.

Now I just want to note here, this is the time when one of the incredible bikes to follow in the list was first seen as a prototype. Just remember that and how far ahead of its time it was when I talk about it more later.

For the next 5 years despite all efforts and all the research and development, no new 250’s came to market that challenged the performance of the Kawasaki A1 Samurai or the then ageing Honda CB 72. So in reality, we had had almost 14 years with no new 250cc motorcycles that were able to break that 100mph barrier.

So we were due some new challengers.

Yamaha RD 250

In 1972 the Yamaha RD 250 was released. Again, despite manufacturers claims, the standard motorcycle produced around the same 30HP as the A1 Samurai and weighed an almost identical 152kg dry The power did slowly increase to 32 HP by 1979 but speed out of the showroom would again not reach that magical 100mph figure.

It was tested at 149kmh or 92.5mph but conditions weren’t great and another test registered 163 kph or 101mph but it had a tail wind. An accepted top speed out of the factory seems to be aboout 95mph

Now I know that we all know that many of the various RD 250’s we knew that did well over the 100mph mark, but remember, I am talking about production bikes in stock factory trim, not tuned motorcycles.

Part of what made the RD so popular though was the ease with which it could be both tuned and ridden. It handled far better than the Samurai or any of the other bikes that were on offer at the time. Tuning shops turned up everywhere, and every 250cc production race series for years was dominated by these bikes which were utterly reliable as well as fast.

Kawasaki S1 250 SS Mk 1

We also got the all new Kawasaki S1 250 SS Mk 1 in 1972. This time Kawasaki unveiled a unique air cooled in-line triple. It produced about 32 HP and weighed in at a similar 150kg dry to the A1. Kawasaki had been hoping for a significant improvement in power and performance over the Samurai but initially it was no faster. Later models had the power restricted to just 28 HP so were actually slower than the A1 had been.

Nevertheless the S1 and later KH 250 were both great sellers for Kawasaki. Despite their brutal power band the new learner regulations meant they were one of the best selling bikes in the Kawasaki range.

Young riders loved the excitement of the ride and many became lifelong Kawasaki enthusiasts based on their first experiences on one of the air cooled triples.

After 1972 we had another 6 year period where the RD 250 had very few challenger’s despite only managing a meagre 2 HP increase in power.


Suzuki GT 250 X7

Finally in 1978 the Suzuki X7 arrived. It still only managed the same 30 HP as the RD but it was lighter at 146 Kg dry. Suzuki claimed it as the first production 250cc motorcycle to reach the magic 100mph mark and we know from the Ducati Mach 1 and Mondial Bialbero it wasn’t, but did it actually reach that magic figure?

Well, in some tests it did, but in others it would barely pass the 93mph mark, so overall it managed just about the same performance as the RD 250.

It was comparable in many ways to the RD, but it didn’t really raise the bar. It only managed to pull up alongside the Yamaha in the race for higher speeds, it never managed the overtake that Suzuki wanted.

Yamaha RD 250 LC

2 years later in 1980 it was Yamaha who again stole the show. The release of the all new water cooled Yamaha RD 250 LC or RZ 250 as it was called in some markets, finally gave us an engine with more power. The liquid cooled lump would produce 35 HP straight off the showroom floor and weighed a remarkable 139 kg dry, a full 13 Kg lighter than its predecessor despite the water cooling.

Although the factory only claimed a 98mph top speed, in test after test it reached the 100mph mark, sometimes in terrible conditions. The accepted figure appears to be around 103mph.

It handled far better than the earlier RD’s too and left all of the competition for dead. It was one of the motorcycles that finally got the industry to realise what an advantage water cooling could be and the tuners loved them.

A race tuned LC 250 could achieve very close to the power output of the TZ250 race bikes of the time and they became so dominant they were simply given their own race series.

Next we have the start of a new generation of giant killers and a very special and very rare bike that some of you may never have heard of.

Honda MVX 250 F

Honda had refused to enter the 2 stroke market, concentrating solely on 4 strokes for their production bikes, but in the world of racing, two strokes were king. Success on the racetrack could also mean success in the sales department, so they finally decided to ditch the failed NR500 project and build a two-stroke race bike to challenge the Yamaha’s.

The format of the new race bike was an industry first. A V formation, 3 cylinder 2 stroke design built in both 250 and 500cc capacity. Freddie Spencer was the chosen pilot and he went on to win the 500cc title despite a season long epic battle with Yamaha and the great Kenny Roberts.

The road bike that followed was the 1983 Honda MVX 250 F. Even the detuned version for the road bike produced a massive 49HP from the two-stroke V3 engine, and the whole bike weighed in at just 138kg.

To make the bike more usable and road friendly, it was tuned for midrange torque and a vibration free ride. It achieved all of that, but the buyers wanted the outright performance and the bike didn’t pass the speed traps at much more than the RD 250 LC, despite the extra power.

Top speed was stated as 101mph and although that was conservative, it rarely tested at much more, with 105mph being the fastest registered speed I could find confirmed.

As far as I am aware, this was Honda’s first two-stroke road bike, but I am sure you will tell me if I have got that wrong.

Suzuki RG 250 Gamma

In the same year Suzuki stole the show with the 1983 Suzuki RG 250 Gamma. It produced slightly less power than the Honda at 45HP but it was built with outright speed in mind.

It didn’t have the smooth rideabilty of the Honda, but with a brutal power band and a lower weight of 131Kg it always just felt a little faster.

This was confirmed by many speed tests and the claimed factory figure of 110mph was actually pretty close to the real world performance of this fantastic motorcycle.

Kawasaki KR 250

Next we come to the story I mentioned earlier that began in 1970.

Although not released until 1984 the KR 250 had first been built as a prototype in 1970. You could say that means when it was released the tech was out of date, but it wasn’t This was an incredible design that had been prototyped and tested in the world of racing and it was unbeatable.

The engine was groundbreaking in many ways and the “Tandem” twin cylinder engine was arranged with two single cylinder engines placed one behind the other with the crankshafts connected by large gears.

Originally they used a 180 degree firing order, but this was redesigned so the pistons rose and fell together which actually decreased the problems of vibration the earlier engines had suffered from.

The exhaust from the front cylinder was routed centrally under the front of the engine with the rear exiting under the seat which allowed a greater lean angle.

The engine was fed by two rotary disc valves, which we have MZ to thank for, and side mounted carbs. The engine made the motorcycle really narrow and it was much smaller and more aerodynamic than any of its competitors.

First developed by the great Yvon du Hammel, it was in the hands of Korky Ballington and Anton Mang that Kawasaki won both 250 and 350 titles in 1978, 79 and 81. Winning a total of 8 titles in just 5 years, with 4 constructors championships thrown in for good measure.

The more I look into this bike the more I realise I think I am going to have to do a video just about this motorcycle, its development and the advances it brought to the world of Two-Stroke engine technology are fascinating.

The KR 250 was made as a production bike for just 3 years from 1984 to 1986 at the end of its illustrious racing career, and it was only made for the Japanese market. It produced 45 HP and weighed just 133kg dry. With a recognised top speed of 112mph it became the undisputed champion of the fast 250cc Race Replica motorcycles.

It didn’t take long for a new challenger to appear though.

Honda NS 250 R

Honda had had their thunder stolen by Suzuki when they released the MVX 250 and Kawasaki had set a new benchmark with the KR250 so they were determined to show the world what they could do.

1985 saw the release of the all new Honda NS 250 R a two-stroke 90 degree V-Twin engined Replica of the world beating Freddie Spencer race bike. It produced a similar 45HP to its competition but this time Honda had made every effort to increase overall speed, and the factory claimed a tested maximum of 118mph.

In independent tests it always achieved over the 112mph record of the KR250, with a fairly recognised figure of 115mph being the accepted top speed.

It wasn’t the lightest motorcycle at 141Kg dry, but it had superb, stable handling for a 250 and raised the bar again for the industry as a whole.

The Four-Strokes

1986 brought more new challengers and the big surprise was that both Honda and Yamaha had decided to produce all new four-stroke contenders for the 250cc battleground.

Now I know Suzuki and Kawasaki did too, but it was the Yamaha and Honda that shone out for me, you can disagree in the comments and I will respond.

The first Honda was the CBR 250, which would later become the CB 250 R and then the CBR250 RR. It continued in production until 1994.

The Yamaha was the FZR250 and as the years passed that too got extra R’s.

They had almost identical performance, making around 45 HP at around 14,500 rpm, The Yamaha weighed in a few Kg lighter at 141Kg , with the Honda coming in at 145Kg and their top speeds were both around 111mph.

Although not quite the performance of the two-strokes, these bikes were seriously capable, and sounded fantastic with the incredible red line they both had. As you can hear in the video.

Yamaha TZR 250

Regardless of the four strokes it was another two-stroke that actually stole the show again in 1986. That motorcycle was the Yamaha TZR 250.

With 50HP as standard and weighing just 128Kg it was a physically small bike, but the TZR 250 was fast.

The first models had a claimed top speed of 118mph and have been tested on many occasions at over 115mph.

They were made in several variants over the years right up to 1996. All were restricted for road use at either 45 or 50HP, but they were easily tuned for much more, and they took over where the RD 250 LC had left off, with an equal dominance in production class races across the world.

Lowering the weight had made a real difference and so the other manufacturers had little choice but to follow that theme.

Honda NSR 250 R

1987 saw the introduction of the next Honda two-stroke in the form of the Honda NSR 250 R. This time Honda gave up all efforts to make the bike user friendly and just focussed on speed. This was another race replica, but of the 1996 Freddie Spencer race bike this time.

Over a 5 year period the NSR won the title 4 times.

As you know by now, manufacturers specs can be a little misleading, but the NSR produced around 45 HP in standard trim and weighed about 125Kg dry. It had a top speed of around 112mph but it was the handling of this bike that made it so special.

Lighter motorcycles can handle better, but often don’t, Honda got the package right, with a beautifully well balanced chassis and great suspension and brakes. This bike made every man woman or child who even sat on it feel like a world champion. Every component down to the last nuts and bolts were designed with speed in mind.

Next, in 1988 we got not one, but two new contenders to try and take the crown of the fastest two-stroke from the TZR. The Suzuki RGV 250 and the Kawasaki KR1, and I will say at this point it gets harder and harder to quote actual verified speeds there is so much discrepency and misinformation.

Suzuki RGV 250

The Suzuki RGV 250 produced around 49 HP when it was released and although it got heavier as time passed it also got more powerful.

The first model was just 128Kg dry. Claimed top speed was what seemed a ridiculous 130mph, but it was tested at over 120mph regularly and the accepted figure now seems to stand at around 125mph.

This was another V-Twin, and the engine was peaky, which won it many fans. It was harder to ride fast than the TZR, but it did improve in time. Later models got a beefed up swingarm and better fully adjustable suspension.

Although the TZR and NSR were fast, and both tunable for more power, out of the crate, straight off the showroom floor, there had been nothing quite as fast as the RGV 250 before.

Despite its speed, one thing it was often criticised for was the almost “polite” standard exhaust note. The factory exhausts were also one of the limiting factors, so many were swapped very quickly. Unfortunately not so many were actually tuned properly afterwards and this made the power band even more peaky and is one of the reasons so few are left in unadulterated original condition now. That, and the fact so many were simply crashed by people without the skills to ride them.

If it hadn’t been for one motorcycle, the RGV 250 would probably have wiped the floor in sales for 1988, but there was another motorcycle that stood in its way.

Kawasaki KR1

Also released in 1988 was the Kawasaki KR1. Kawasaki had moved on to a more standard Parallel Twin engine from the Tandem Twin of the KR 250. The KR1 engine produced 55HP and the bike weighed in at just 123kg dry. Making it both lighter and more powerful than the Suzuki.

Top speed, in line with the Suzuki, was also claimed to be 130mph, but it is the only motorcycle on this list where that claimed top speed was routinely beaten in real world testing. The bike was tested at 131mph on numerous occasions and on some tests it went significantly faster. One test from a relatively reliable magazine showed an staggering 136mph top speed.

This was a raw, visceral motorcycle with no frills, and the riding experience was extreme. Below 40mph the power delivery was as uneven as a saw tooth blade, but once the engine was over 7,000 rpm it took off like a scolded cat with fireworks attached to its tail.

That didn’t stop either, The engine would rev and rev until it passed the maximum power at 10,500 rpm where the power gently dipped until 11,000 rpm rather than falling off a cliff like the RGV did.

This made it so much easier to ride fast, that it became the bike of choice for production racers in the 250cc class overnight.

Steering was razor sharp and this motorcycle even made the TZR look big in comparison.

Something else didn’t stop. That was the research and development department at Kawasaki.

Kawasaki KR1S

By 1990 they had improved the KR1 even more and we got the incredible Kawasaki KR1S. Weight was up a fraction at 131kg but power had been increased to 59HP too. The power band was pushed higher and the KR1S didn’t come alive until over 7,500 rpm. Under 3,000 rpm it was described kindly as “useless” by one journalist and I have to acknowledge, this was not a motorcycle for pootling around on. It was a motorcycle built purely for speed with steering so sharp even some racers found it hard to handle.

This really was as close as you could get to a race bike for the road.

Despite Kawasaki still only claiming a 130mph top speed, it was regularly tested at over 135mph with one test even reaching 139mph. FROM A 250.

It became the fastest mass produced 250cc motorcycle for the road and 35 years after the KR1 was first unveiled it is still considered one of the purest Road Going Race Bikes ever built.

Suzuki RGV 250 SP

Three years later, in 1993, Suzuki took the RGV 250 platform one stage further. The Suzuki RGV 250 SP was a fire breathing monster of a two-stroke producing 61HP at 11,000 rpm. It had put on weight and now weighed in at 145kg dry, but it was a much easier motorcycle to ride fast than the previous RGV.

The 250 SP could make any half decent rider look fast whereas the old RGV and KR1S needed a rider with real skills to get the most out of it. A claimed top speed of 127mph actually seemed fairly accurate for a change, and its power delivery was much smoother than the Kawasaki with a stronger midrange unlike the earlier incarnations.

Despite the extra power it never dethroned the KR1S as the fastest production 250 but it was a very close fight.

The Aprilia RS 250

That fight was finally won in 1994.

A new kid on the block had arrived. Aprilia didn’t have the Historic name of some of the other Italian brands, but they had some fantastic engineers and they had a trick up their sleeve. That trick was Max Biaggi.

They had already begun to climb the ladder of success with Loris Reggiani, but it was the outspoken and extrovert Biaggi that would prove the perfect figurehead for Aprilia’s quest to prove themselves on the world stage.

The Aprilia RS 250 was described at the time as the perfect racing 250cc motorcycle, and it still represents the pinnacle of two stroke technology, producing an unheard of 72.5HP at the crank and over 64HP at the rear tyre in standard form, straight off the factory floor.

It weighed 141kg dry, but had better balance than the TZR, KR1, NSR or the RGV. It won 5 out of the next 6 250cc titles and over the coming years, it would amass 9 titles and 9 constructors championships, making it possibly the most successful race bike ever made.

In road trim, it had a claimed top speed of 130mph but this was conservative. Motorcycle News tested it at 138mph and I have seen plenty of even faster results, but they have to be seen in context, as some journalists and testers are less than reliable let us say.

Regardless, this was the fastest 250cc production motorcycle ever built, and it still holds that title today.

Some Honourable Mentions

Now, as usual, we do have a few honourable mentions.

First, I would like to give some credit to both Cagiva and Aprilia, The work they did producing the Aprilia RS125 and now fabled Cagiva Mito really was groundbreaking. The Mito came slightly earlier but both of these incredible 125cc machines produced over 33 HP and would smash the 100mph mark. Their rivalry was legendary and would dominate the small capacity racing world for many years to come.

The Cagiva Mito still has one of the most devout followings of any motorcycle ever built and they have come together to make sure these fantastic bikes are kept going for as long as possible.

Although different, both the Cagiva and the Aprilia should be recognised as a major step forward in two-stroke performance.

Another motorcycle worth a mention is the 1977 Benelli 254 Quattro. This was an amazing across the frame 4 cylinder four stroke that had been built to take on the two-strokes. It was only 2 HP short of the Suzuki X7 released a year later, producing 28 HP. It also weighed in at a remarkable 122Kg dry according to the spec sheets, although this weight was hotly debated. If true it meant this across the frame 4 was lighter than many of its two-stroke competition.

Claimed top speed was 97mph but it came in somewhere between 93 and 95mph in most tests depending on where you find the data. Regardless of its top speed, this was a remarkable piece of engineering. It had bags of torque and when compared to the four-stroke Honda’s that had followed the CB72 this bike was lightweight and very nimble, with much better acceleration.

As a piece of engineering genius you have to admire the work that went into making those four 60cc cylinders sing a most wonderful tune, right up to their 10,500 rpm limit. Even if just for that exhaust note, they should be remembered.

There are two other bikes I would like to mention too. One I had never heard of until I began this video.

The bikes are related but were aimed at different markets, I’m not sure if they got the market research right here because I for one would have liked to see the model we never got.

Those two bikes are Suzuki’s. In 1990 the Suzuki GSX 250 F Across was released in Japan and I believe they at least made it as far as Australia. To be honest I am not sure how many reached anywhere outside Japan as it is very difficult to find any confirmed figures, either for numbers manufactured or sold. A year later, much of the rest of the world got the GSX 250 S Katana.

The Across was a four stroke, fully faired sports/touring/commuter bike, producing 45 HP at 14,500 rpm and it had a top speed of 110mph, it just doesnt quite look like it can make its mind up what kind of bike it is. It does look like a fantastic motorcycle and if any of you know much about it then please let me know in the comments.

The Katana was a platform that had become a successful seller for Suzuki, and I guess releasing a slightly detuned version of the Across engine in a naked sportster was maybe a safer bet with the domination of two-strokes in the 250cc world championships.

The 250 Katana produced 40 HP at a slightly lower 13,500 rpm and despite the lack of a fairing would reach speeds of around 108mph.

These bikes would have inevitably made more impact if it wasn’t for the domination of the two-strokes at the time and I wonder how far the design may have been pushed if circumstances on the world stage had been different.

Thoughts From The Shed

Maybe we wouldn’t be stuck with the tame, boring, 250’s we have today.

Which brings me to one of my comments earlier.

So, now we have been through the list, what do you think about the fact that the 250cc motorcycles of today, seem to have none of the flair and sheer excitement that the bikes from the past brought us?

Is there any wonder new, younger riders just don’t get excited about them? I don’t ! and I love anything with 2 wheels.

Why is it that the latest crop of 250’s produce so little power compared to the bikes in this list? And don’t just blame emissions. Remember, an efficient engine produces more power and less emissions.

Why is it the new bikes are so much heavier too?

Even accounting for the addition of catalytic converters and ABS systems there is no way a motorcycle 60 years old should be lighter than its modern counterparts.

Is this the sort of evolution you want?

Or is the industry just trying to con you into buying bigger, more expensive motorcycles, to keep their profits high even when sales are falling?

Why has around 64 years of research and development, by people who are supposedly some of the best engineers in the world, have actually got us nowhere when we compare the performance of 250cc motorcycles?

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