Kawasaki KDX 125SR


Make Model

Kawasaki KDX 125SR


1993 -96


Two stroke, single cylinder, with KIPS


124 cc / 7.6 cu-in
Bore x Stroke 56 х 50.6 mm
Cooling System Liquid cooled
Compression Ratio 8,0:1


Keihin PE28 carburetor


Spark Plug NGK B9EV or B9EVX
Starting Electric

Max Power

24 hp / 17.8 kW @ 9600 rpm

Max Torque

21.8 Nm / 16 lb-ft @ 8600 rpm
Clutch Multi-disc clutch in oil bath


6 Speed
Final Drive Chain

Front Suspension

Kayaba 48mm telescopic hydraulic fork reversed KAYABA 48mm, double adjustment + adjustable spring preload, prepared
Front Wheel Travel 300 mm / 11.8 in

Rear Suspension

Uni-Trak adjustable for preload
Rear Wheel Travel 320 mm / 12.5 in

Front Brakes

Single 260mm disc

Rear Brakes

Single 220mm disc

Front Tyre


Rear Tyre

Wheelbase 1455 mm / 57.3 in to 1480 mm / 58.2 inaccording to chain tension
Seat Height  950 mm / 37.4 in
Ground Clearance 365 mm / 14.3 in

Dry Weight

98 kg / 216 lbs

Fuel Capacity 

9.0 Litres / 2.3 US gal

Standing ¼ Mile  

20.3 sec

Top Speed

64 mph / 103 km/h
Related Link Kawasaki KLX


This (or should I say these?) were the most popular test bikes ever. Now I'm not saying that the KDXs' keys were the first to disappear when we got into the office, oh no.

The KDXs were popular with the sort of people who can't be bothered to wait for the keys before riding them. Bastards.

Rupert had his for about five days before it was stolen and I managed to keep the one I had for nine days before it went too.

Judging by the reactions of kids to the bike it should be just as popular for Kawasaki in the sales charts. The amount of attention from the up-to-18 age group was embarassing. It was easily more than I got from everybody when I had the FZR600. To be this popular up Westgate Hill on a Saturday I'd have to be giving away LC parts. It was all a bit unnerving. I felt like Jason Donovan and Kylie Minogue rolled into one (what a thought).

First impressions of the bike were somewhat less than favourable, though. I mean, if you were faced with a 210 mile trip home up the Al, to be completed in as little time as possible, what bike would you choose? Unless it was all you were allowed to ride, I don't imagine that a restricted 125 would be your first choice. It wasn't mine either, but seeing as Rupert was only giving me a choice of one, I didn't have an alternative.

It had been six years since I passed my test and sold my restricted 125 to some other poor sod, and I had never ridden a trail machine before. After about ten miles the nearest thing I could liken it to was the Luton van I'd been driving the week before. The seating position is very similar; upright and high enough to see over cars, hedges etc.

Making decent time also relies on the same process as driving a large van, where keeping up momentum is the be-all and end-all. Thanks to the emasculated engine, manoeuvres have to be planned long before they would be on a more powerful bike.

Overtaking is a case in point. It is, how shall we say, an exact science. There's no just dropping it a couple of cogs when a gap appears in the outside lane. Trying this will, at least, leave you with a very irate motorist up your exhaust pipe, and at worst — well, I just hope you like the smell of oak.

You have to work up to the same speed as the other traffic and slip into the gap as it goes past. Whilst this sounds fine in theory, I lost count of the number of times I had everything set up, only for some company rep to come blasting up at about 90mph and fill the space. This invariably left me stuck at about 40-45 mph behind Mr & Mrs Normal (Who's normal these days? — Rupert's psychiatrist) in their Metro.

Once you're settled into the routine, the first real problem with the bike presents itself. At (comparatively) high speeds it vibrates noticeably. This may be an advantage for any readers who frequent the type of clubs where leather caps and long coats are de rigeur but it just left me with a sore botty (same sort of feeling as visiting the aforementioned clubs).

In fact the vibrations were so bad that, after 600 miles, the exhaust header nuts came loose and oil spat past the exhaust gasket. Not exactly what you would expect from a new bike, but once tightened up again the nuts gave no more trouble (at-least for another 250 miles, that is, until it was stolen).

Although fast A roads and motorways may not have been its forte, the KDX was much more at home on back roads. A combination of good cycle parts and restricted engine means the bike can be thrown about without a hint of danger. Whilst the motor puts out about 24 ponies in unrestricted form, the 12bhp version means the frame and suspension can have a day off.

The brakes (single disc front and rear) were adequate, but not confidence inspiring. The front worked quite well, but the rear must have been designed by a trail rider. It needs a large input for very little effect, which is great on trails where there is a danger of locking it up on loose stuff, but not so good on the roads. While they never failed to stop me, even quickly when needed, I think I would reserve  judgement on what they must be like on the 24bhp model.

Not so the suspension, which is undoubtedly the bizz, with non-adjustable forks (41mm on a 125!) and Uni-Trak rear (5 way adjustable for preload) shrugging off the best (worst?) that British Gas etc could throw at it. This was definitely the best point about riding the KDX. No need to teeter your way carefully around the streets avoiding manhole covers as you have to on race replicas with their solid suspension at low speeds. Just pick a line, there's no need to deviate.

With the high seat (34 inches) letting you see a long way ahead, and consequently letting you plan your next move earlier, this all combines to make the KDX an ideal back lane scratcher. This was demonstrated when I was back home on a little jaunt up a country lane near where I live in Geordieland. It's the sort of lane that's two cars wide (if they're Minis), hedge-lined and twisty. Also, thanks to its proximity to a quarry, it has various surprises hidden round bends, such as lumps of earth, gravel and every now and again a new stream running across it. The KDX was the quickest bike I've ever ridden down there, no exceptions.

However, back in learner-legal land the engine is the most important thing. Cycle parts, and how well they work, are to a certain extent superflous; it's all about whose bike is quicker than whose and this is where the KDX doesn't quite cut it. I'm sorry but it's not the bike to beat your mates on if they've got TZRs or RG125s, etc. The large frontal area alone means you're always going to be left a few frustrating mph behind them (and within the national speed limit) on quick roads.

If back lane scratching is easy, then commuting is a doddle. Forget all you've heard about mopeds being the ideal inner city transport, the KDX wins hands down. It's so easy to manoeuvre in and out of cars, whether they're standing still or moving, that you'll reach point B (as in from point A) quicker than almost any other bike from tuned EXUP down.

A tiny turning circle helps here. There's no need to pick your way gingerly between rows of traffic, as on bikes with limited steering lock.

On the aforementioned Al ride I came to a 2 and a half mile traffic jam and spotted a Porsche that had passed me a few miles before doing a ton plus. Whilst all he could do was sit and fume, I made good my getaway. He didn't pass the little Kawasaki again until about 30 miles down the road.

If at all possible, try to avoid taking a pillion. The seat is more than large enough for two but passengers tend to slide down it, pushing you to the bottom. This gives you the feeling that your knees, hands and ears are all at the same height, and makes the front end seem decidedly vague.

One other complaint from passengers was the height of the bike when getting on and off (wasn't it, Joan?). As the seat height is a couple of inches taller at the rear, vet all passengers carefully and exclude any with a less than 34in inside leg.

If you think the tank looks small you are right. Holding nine Litres
it will last about 75 miles of flat out riding before needing reserve. This worked out at about 45 mpg, and under the same conditions you could expect to fill it up with two stroke at the rate of 500ml. per 175 miles.

To get to the oil tank you first have to find the tool kit (little black compartment between the seat and footpeg), extract said kit and then select the correct socket. This is the one which will undo the three bolts holding on the right hand air scoop thingymagig and then you can actually see the oil tank. Take the crosshead screwdriver to undo the screw holding the cap on, and you're ready to fill up. Refitting, as they say, is a direct reversal of removal.

Doing this gives you a chance to admire the Kawasaki's finish. This is generally very good apart from the exhaust, which was showing signs of rusting slightly around the edges after only 1,000 miles, so God only knows what it would be like after 5,000 miles of being ridden through peat bogs and the like.

If you're going to spend £2,000 on a bike like this, then please, please, please do yourself a favour and take it trail riding. What's the point of spending all that dosh on a dual purpose bike and the only using it for half of what it was made for?

If you've never tried dirt riding before, pick an easy trail and I guarantee you'll love it. No amount of ham-fisted riding seems to upset the KDX, and a small dent in the exhaust was all it had to show for the couple of times I dropped it off road.

Is any 125 worth two grand? Certainly it's about as good a 12bhp motorcycle as you're going to get. Everything works at least adequately (brakes), if not exceptionally (suspension, headlight). The only fly in the ointment is the high speed vibration.

If I were a learner again, however, I wouldn't even bother buying a 125; I'd find a test centre which hired bikes out and pass my test that way — either that or buy a cheap secondhand bike which I could sell for the same price I'd bought it for. The £2,000 would make a nice deposit for a GPZ900R or similar.

But if you're the sort of person who just can't live without this year's model, can stand the thought of 15% depreciation before the ink on the sales slip is dry and has an alarmed garage complete with several Kryptonites this could be the bike for you. Buy it, pass your test as quickly as possible, de-restrict it and you'll be looking at some serious fun.