Spa Kat track test – Donington 1st September 2014

On the 1 September I took the Spa Katana to Donington for a full and thorough shakedown. It’s the first time I was really able to let it fly, and happily at a track I know well. The whole feature was published in the December 2014 edition of CMM, cover seen here (and doesn’t she look pretty?!)


Spa Katana – Track test at Donington GP

01-09-2014 Donington Park trackday photographs

Ok, we’d had a run out at Spa, and a single stolen session at Cadwell’s 80th Birthday gig, but really – the Kat hadn’t  been pushed yet. So on 1st September 2014 I rocked up to my “home” track and decided the give the old bus a better shakedown.

Amazingly, the bike didn’t need much to prepare for this: Sealing some minor oil leaks, small tweaks to suspension and a run on the dyno to get the carburation spot on were all we needed. Well, to be honest, all of that was so minor, the Katana rolled out of the van at Donington with none of them done! 2 sessions into the day, a single tweak of the rebound clickers on the rear shock and a tiny dab of instant gasket (in lieu of a new sealing washer on a head bolt) sorted everything well enough. The carbs were close enough to a good set up to be more than workable. The Kat was now ready for a proper blast around the enchanting curves of Donington’s newly re-appointed full MotoGP circuit.

Let’s begin by breaking the big news – this bike isn’t hard to ride fast. Its manners and performance are nothing short of exceptional. But, to get the very best out of it needs a firm hand and strong sense of desire. Here’s what we found out during our day at the track.

First impression.

Even standing still in pitlane the Katana demands attention. Its quirky 80’s shape quickly grabs the eye – it’s one of those rare designs that look like nothing else, ever. Being race-prepared as well, this one is pretty unique in the UK. It makes people stop and stare. Maybe they’re thinking “why?” or “what is it?” but the engagement seems frequent and warm enough to suggest that overall the bike is memorable for the right reasons.


It’s sparkling white paint highlights the best of the bodyworks form, whilst the use of darker colours behind the slice of white saddle, attempt with some success to mask the unfashionable length of it. Chopping a Katana frame and seat to shorten the bike has been done many times. It’s been done here too, just with careful choice of colour and not an angle grinder. A welcome dusting of gold from the wheels, brakes and forks deliberately embellish the otherwise monochrome palate.

I really have to pinch myself that I made this – it looks far too gorgeous to be a product of my flighty and tortured mind! I’m happy it looks this way – opinions gathered wherever it’s shown joyously suggest that it’s not just me that thinks it really is bloody gorgeous, and better in the flesh than pictures.

Riding it

It’s long, it’s heavy and it hasn’t got forks, wheels, tyres, suspension or brakes that could be considered modern. It’ll be hard to ride fast. Won’t it?

Well, although those assumptions were already partly dispelled in a handful of sessions at Spa and a single session at Cadwell, there was still a job in hand to work out how much further we could shred these notions here at Donington.


The snaking, diving, climbing run out from Redgate through Craner Curves and back up to Coppice is one of the best sections of racetrack in the world for a motorbike; constantly changing direction at high speed and never being upright concentrate the true feeling of speed on a motorcycle into 45 fun packed seconds. Coaching at the Haslam school means I’m a genuine 4,000 plus laps into my understanding of this track – thus there was no better place on earth for me to test this bike!

Beginning by firing the Kat up, it doesn’t unleash quite the sound you’d expect. A day at Donington means you’ll see plenty of full-up 737’s scuttling out of next doors East Midlands airport. Although the Kat looks like it’ll give them a run for the noise abatement violation of the day award, actually, it’s well muted (tested at 98.7 dB) by the tiny 29mm outlet on the original (and beautiful) 1982 Yoshimura pipe. There’s a whole bunch of power being lost by using this unmodified silencer, but the race at Spa has a 101dB noise limit, which is reason enough to leave it as is. I’m assured by people watching on the day that it sounds great when actually on the move, which is probably as much to do with the induction noise from the four 35mm Keihin CR carbs ripping air through the open bellmouths as the exhaust.


The riding position itself is comfortable and yet race-ready. For a 5’10” bloke like me the reach to the bars is about as far as you’d want it to be, but otherwise the seat and footrests support you in the right places for a long stint on track.

Sat still the Katana it lets you know it’s big, long and heavy. This soon disappears once on the move. You can still sense it’s bulk, but it doesn’t affect the steering in an adverse way.


I ride 2014 Fireblades around this track usually, and if there’s ever been a bike more capable of easy speed then I have yet to ride it, or hear of it. They make riding fast stupidly easy. I often describe them as having “video game” levels of simplicity to control.

Well, the Katana can’t get near this feeling for outright ease of use, but it’s trump enjoyment card isn’t about being easy; it’s weight, it’s length, it’s skinnier than usual wheels – they firmly plant a seed in your head that going quickly may be off limits. Well, it’s not true. Simply trusting the feedback the bike gives, and not the thoughts of what it should be capable of, and it aces the feeling of enjoyment you’d get from any modern bike by miles – Fireblade included.



You’ll be working harder for every scrap of speed you muster, but there’s plenty to be had, and it’s safe – it’s just not going to be given to you on a plate. If you’re too polite to push it when all the feedback says you can, you’ll still travel quickly enough to have fun. But be forceful and it really digs in. It’s grip on the track seems to increase as it’s pushed more; it turns sharper and thrusts the track backwards with real venom when you ask it to accelerate.

The harder I pushed it the more I shook my head in disbelief and delight. I couldn’t get it to tie itself in knots, I couldn’t make it misbehave, I couldn’t do anything other than just go faster. The firmer the hand, the better the response – isn’t that a real riders bike right there? Full credit to Avon for their exceptional AM22/23 tyres mounted during this test – again, as at Spa, the grip, feeling and confidence levels they inspired provide the foundation to just being able to push harder and harder without a moment’s concern. Brilliant.


Even at speed, the bike turns quickly and precisely. I love the Old Hairpin; it’s approach from the bottom of Craner Curves is taken at about 115mph providing the perfect reception into its fast flowing embrace. Once a little speed has been scrubbed off and the bike turned, you find yourself asking for maximum lean and a fistful of acceleration all at once, with 80mph of moving tarmac underneath you. This will find out pretty quickly if you’ve got a bike that wants to stay in line. The Kat, again, behaved immaculately through here. Its balance is a joy, and the frame flex that could be expected on a stock Katana without our significant bracing was delightfully missing. 100% proof that this frame bracing works.

01-09-2014 Donington Park trackday photographs

Riding hard with no steering damper can cause trouble, but it’s testament to the overall balance and impeccable suspension that it really doesn’t need one. Aside from the odd little patter in the hands out of the second gear corners under acceleration you’d really never know it wasn’t already so equipped.

The brakes

It’s all very well enjoying how well it goes around corners, but does it stop? Donington is famous in racing circles for boiling brake fluid, as its four hard braking zones are all bundled into the same quarter of the track. That’s a really stiff test for the tiny 2 piston Brembo calipers on our Katana. Supporting the tiny calipers are the brilliant pairing of an AP Lockheed Master Cylinder and Dunlopad Race compound pads. These bite into a well-used pair of stock ZX9R discs. The performance these brakes deliver is absolutely incredible. The brakes are very powerful, yet they have a lovely feel. Stopping the bike hard enough to be competitive still leaves that last little emergency pinch of braking power left over ‘just in case’. And did they fade? Nope, not one little bit. Stoptastic.


The Suspension

Good brakes need good forks, and the very effective set up the Kat wears at the front does allow man-sized chunks of braking to be thrown into a corner approach. The carpet-like ride quality of the forks means bumps and rattles on the way in don’t impede confidence in the bikes ability to turn, and when it’s dropped in with the brakes still applied, the bike leans without resistance. Perfect. Our shaved left-hand engine casing creates all the ground clearance we need as well, so losing the alternator was another well planned move.


Once dropped onto its side, the Jon Slenzak crafted suspension soaks up bumps and changes in balance from braking or accelerating perfectly, ensuring that once you choose a line, the bike will stay on it – hugely reassuring.


Once it’s been arced through the turn with plenty of gusto, standing the big Kat up and firing it out means being assertive with the throttle. Riding Donington requires a little patience with the throttle sometimes – waiting just a fraction longer on corner exit means the bike has turned significantly more, and thus the throttle can be opened significantly harder and still keep you in between the kerbs. Sitting atop a bike with as much instant grunt as the Kat makes this technique really sing. Which brings us to THAT engine – 1170cc of tuned, legendary, air-cooled Suzuki GSX…

That engine

Anyone that’s been paying attention in the last 30 years will have noticed that the big GSX’s have an ardent following. And now, in this bike, I can really see why. If it were down to just one word to describe this motor it’d be an easy choice: Grunt.

SuzukiKatana-25 SuzukiKatana-27 SuzukiKatana-19

The Kat’s throttle has the kind of connection to the engine that all motorcycle racers dream about. I’ve heard amazing things about the instant torque of the electric motors fitted to the TT zero bikes, and that’s where I’m most likely to draw the best comparison for this motor – it’s spaceship levels of torque and smooth relentless acceleration are a joy to wring out of an opening throttle. It will rev freely to 9,000 rpm, but you don’t really need to. It’ll pull from under 4,000rpm and can produce clean acceleration from anywhere in that entire range. I like opening throttles on anything, but this bike is my new favourite. This track test was done pre-dyno set-up as well, and having now dropped 2 jet sizes and 1 needle position since, we’ve crisped up the response even further. It didn’t feel bad, but now? – its even better.

Whilst on dyno test, torque was measured at a monstrous 79ft/lb, which is the same as a 2014 BSB Superstock spec ZX10 run on the same Dyno. Impressive? Hell yeah. Power was a respectable but not earth-shattering 124.9bhp. CMM’s own GSXpert Pip Higham is confident that changing the pipe for something more free-breathing could release as much as another 15bhp. Tempting, but I’m not ready to ditch this very quiet and very pretty pipe just yet.

In conclusion

By the end of the day at Donington I was convinced that the bike is a weapons grade classic racer. I’d not enjoyed a session on track as much in living memory, and the bike was ridiculously well set-up right off the bench. It’s days like this that payback with interest all the hours, days, weeks of thinking, buying, tinkering and distress that a build of this magnitude throw into your life. I can forgive the Katana almost anything now, because it is just so damn good to ride.


So, I’ve waxed lyrical long enough – it’s clear, for all the heartfelt reasons above, I really love this bike. But are there any bits that aren’t up to scratch? Well, on track this bike is amongst the most enjoyable things I’ve ever ridden, even on an open track day packed with modern sportsbikes such as we used for this test. The harder part of Katana stewardship comes in the garage – on this day we had a cylinder flood thanks to a float valve jamming open and the total loss ignition/Lithium Ion battery combo needed constant attention with a charger. Some of my rewiring of the fabulous new loom to incorporate a rev counter had caused a non-starting issue too. Are these reasons to dislike this bike? Not at all – mere gripes. Refining this bike is still on-going and issues like these are all fixable, and in fact were all sorted well enough on the day. The only thing you need to take on board is that unlike a 2014 Fireblade you definitely aren’t getting a season of track use out of it with just tyres, fuel and oil changes. But then, tinkering is why we all love a classic anyway, isn’t it?

Will it race at Spa next year? I finally know it’s good enough. But there’s a problem. This Kat has wormed its way so deeply into my affections that I really don’t know if I can let it roll onto a grid and risk seeing it destroyed. I guess that’s a consequence of finally having made the nicest bike (not to mention most expensive) I’ve ever owned.

Maybe it’ll never truly be finished in my head until it has raced. At least now I know if I do then it’ll be a pleasure to let it off the leash. Every part of this Kat can carry the fight, it’s purely my choice left to make. The last remaining conundrum of the thousand it took to get this far.

Well, if you’ve followed the build this far, you’ll realise it wouldn’t be simple now would it?

Watch this space and keep an eye on the entry list for #117 in the 2015 European Classic Endurance at Spa!





1981 GSX750S Katana. Lightened with Lucky 7 bracing kit added.


Front 1985 GSX-R750 18×2.5 wearing 110/80-18 Avon AM22 Endurance Compound tyre

Rear 1986 GSX-R1100 18×4.00 wearing 150/70-18 Avon AM23 Endurance compound tyre


1985 GSX-R750 yokes and fork bottoms with disabled Anti-Dive units. 41mm Tarozzi Titanium Nitride ZX6R stanchions, custom fitted with ZX6R Andreani Race Cartridges and Hyperpro progressive 0.95Kg/mm springs.


YSS G-362 TRCL –piggyback gas reservoir shocks 360mm long.


Yamaha XJR400 modified to take 20mm Triumph Sprint RS spindle.


Discs – Kawasaki ZX9R 310mm

Calipers – Honda NT650V Deauville Brembo 2 piston sliding pin

Master Cylinder –AP Lockheed Adjustable ratio CP3125

Pads – Dunlopad Race compound SDP623

Mounting plates – custom made Hejira Racing adapters


Throttle – Motion Pro Quick action throttle/cables

Rearsets – custom made Hejira Racing footrest plates, footrests and linkages.


Head – GSX1100 EFE Ray Debben ported head with 1mm oversized valves on inlet and exhaust, Reground Kent Cams, slotted APE cam sprocket, heavy duty camchain and tensioner blade, manual camchain tensioner supplied by Grumpy1260

Block – Rebored for 1170 Wiseco Pistons supplied and rebored by Grumpy1260

Bottom end – from GSX1100ES with rebuilt and welded crank, Star racing hi-flow oil pump gears, Grumpy1260 modified heavy-duty clutch basket, Trac-King clutch plates, removed alternator.

Exhaust – 1982 Yoshimura full system.

Carbs – Keihin CR35mm Smoothbore Roundslide carbs, with open bellmouths from Allens Performance – UK Keihin dealers.

Cooling – 13 Row Setrab 330mm oil cooler with AN6 fittings.


Dyna-S mechanical advance ignition, Dyna DRL-300 rev-limiter, Dyna 3ohm Coils, Taylor leads. Skyrich Li-Ion battery, running total loss.

Custom race loom made by

In numbers

Maximum Power: 124.9bhp at 9,000rpm

Torque : 79 ft/lb at 7,500rpm

(power and torque measured on dyno)

Weight : 225Kg (estimated)

Total cost – £12,500 (and counting)

A word from our sponsors – a premium visor care company may never have invested in something as oblique as a Katana for marketing before, but thank heavens did. Like what we did with the Kat? Buy some more, we’ll do it again!

And the video…Remember, no tyre warmers were used in the making of this production which is why the first two laps are gentler than the last one!

Spakat, Fast Group, Donington 1st September 2014