Sunday 28 November 2021

Kawasaki GPz1100

When I first read about this bike I was deeply envious of the guys who would be able to buy one brand new (£3000 in 1983). Not people like me, though, like thousands of other bikers I could only read the monthlies and dream. Every time I got a pay rise I started considering signing my life away to the HP but they put the prices up to even more extreme levels and I never seemed to catch up. It wasn’t until Feb ‘87 that I came across a bike I could afford - a 1984 Kawasaki GPz1100 for £1800 in a dealer’s showroom. The going rate was around £2200, I could only guess that the dealer, who dealt mainly in Italian exotica, wanted shot quickly of the the Jap crap demeaning his showroom.

I had to have it. I read and re-read every road test of it. 148mph top speed, 120hp, the standing quarter in just 114 seconds and an engine that had its roots in the ultra tough DOHC Z1... and it could all be mine. First impressions were a little disappointing. My immediate reaction was blimey, it’s heavy, hope I don’t drop it on the first roundabout. The clutch lever travels a long way before you start to move; adjusting it makes little difference as it releases over too short a range.

The suspension and anti-dive is firm with little front end dive when hauling on the brakes, the best I've experienced with just the right feel for my tastes. They've got me out of trouble on a few occasions. Even after two and a half years it still feels a big, heavy bike which it certainly is at 570lbs with a gallon of fuel.

It's a handful around bends, the performance is at the top end of the rev scale, 120hp at 8750rpm with peak torque of 73ibft at 8000rpm. This is a nuisance as you have to dial in 6000rpm before it wakes up and by the time you've got it wound up, it’s time to throttle off as yet another four wheel tin box gets in the way. The riding position has you crunched up racer style which, whilst being right at 100mph, is a pain when riding around town getting stuck in traffic jams. In town, your wrists and lower back soon start complaining.

My girlfriend preferred the pillion of my 1980 Suzuki GS1000, due to its deeply padded, squashy seat - on the Kawasaki, pillions catch too much wind blast over the top of the rider. The heavy handling causes my riding style to be much more ragged than when I’m on the Suzuki. I still haven't mastered the GPz, every journey is like the first time I rode the bike and I can only relax on the odd occasion when I have some room to get up some speed and fall into a fast, swooping, uninterrupted rhythm.


The half fairing gives better protection than the GS and I find that I can cruise at an almost comfortable 110mph on the Kawasaki compared with just 90mph on the Suzuki. The mirrors could be much better as the rear view is minimal. I've only done 6000 miles in the time I've owned the bike as I only like to use it for day trips and town blasts rather than all out touring. I’ve replaced all three sets of brake pads recently (EBC and £14.50 per set), a set of tyres once (they were on the way out when I bought the bike) and the chain adjustment has been minimal.

The engine is fuel injected, controlled by a black box housed in the tail section that costs £400 to replace if it should go wrong. There are a range of sensors for engine temperature and speed, air temperature and throttle openings. Perhaps it is in the nature of two valves per cylinder designs, at large capacity, to require fuel injection to make lots of power. On the fuel tank is a LCD display with warning lights for oil and battery levels, fuel injector faults and a fuel gauge which is way too pessimistic.

From early after I got the bike, the engine misfired when I tried to rev past 6000rpm with the fuel injector warning light flashing on momentarily. As the bike would still do 100mph I was in no hurry to sort it out. The exhaust pipe gaskets soon blew and I had trouble with the side stand cut out switch. I replaced the gaskets by myself which is an incredibly fiddly job because you have to line up all four pipes whilst trying to stop all four gaskets and eight split collets from falling out.

After replacing the side stand switch, I still had the problem of the bike misfiring on its erratic, juddery way past 6000rpm. Eventually, one night, seven miles from home it wouldn’t start. I fiddled with all the connections and battery leads to no avail. It was completely dead. I had to have the bike picked up. The fault? An engine temperature sensor - cost, £25 plus pick up and labour, £70.

An exhaust gasket blew again. Once more I fiddled with four gaskets, eight split collets and four pipes. Soon after, they blew yet again. I swore at the bike and threatened it with the horrors of a visit to the dealers. So far, the last set have lasted.


The bike has had an oil leak, the starter motor oil seal was the prime suspect. Having to replace half a pint of oil every 200 miles or so (less if not thrashed) was getting expensive as I use Silkolene 10/40. I’ve changed to Shell Gemini due to its greater availability. At its first service since my ownership, the oil leak was judged to be coming from the air box, oil dripping down onto the starter motor cover, as this could have been expensive I decided to ignore it for the moment.

The bike also weaves at 100 plus mph solo, which wasn’t cured by fitting new tyres. Maybe the suspension settings or Unitrak bushes are to blame? The half fairing meant it was susceptible to side winds and the whole plot could become quite frightening two up in heavy gusts.

The engine idle speed sensor was also under suspicion since tick over was erratic and the bike would often conk out unless you kept blipping the throttle. Luckily, it only needed the injectors balanced. This helped my riding to become smoother as there was no longer a degree of uncertainty connected with whether or not the engine would respond properly.

The police didn’t seem to like the bike much. Going up a hill at 55mph when the clutch went and I was stopped by the plod who gave me a ticket for speeding in a 30mph zone. He didn't offer to help push the bike up the hill either. It was seven yards push, stop and rest, seven yards again. I was only a mile from home but it took ages - I was drenched in sweat, shaking with muscle tension and my back ached for weeks afterwards.

If this makes the bike seem a bit of a pain in the arse it does have a good side. Once all the faults were fixed, I was able to take it up to 130mph two up, and I could have done much more except that my pillion was getting thrown off the back by the wind pressure. It looks impressive, but can be confused with the 550 from a distance and, these days, looks a little dated, although I do like the overall appearance. In the main, a good sploshing with hot, soapy water and a sponge keeps it clean.

When cruising for any distance on a bendy route, where you have to keep the speed down, I find engine vibration through the bars gives me severe pins and needles in my hands after 15 to 20 miles. The later Kawasakis, from the RX range on, were rubber mounted, a pity it wasn't done well enough on the GPz. It's also very noteworthy that Kawasaki have now dropped the fuel injectors.

Other problems... downshifts need the gears engaged firmly, if you don’t you will get false neutrals; the suspension settings require too much pissing about so are left as they are; battery removal requires lots of bits taking off the bike (to be fair, it’s very sturdy and has never failed to turn the engine over), and the fuel pump and injectors make an annoying noise when the ignition is switched on.

The bike went into a Kawasaki dealer due to the high oil consumption. They found a heavy build up of carbon and a broken ring on one piston, a camchain in need of replacement despite only 20000 miles and the rear shock started leaking. Given the complexity of this bike’s electrics, and its apparent fragility, I have to say that I wouldn't buy another, although I'll keep this one as I can’t afford to trade it in. My conclusion is that the GPz1100 certainly does not live up to its makers reputation. Just to cap it all, I've just had to replace yet another engine temperature sensor...

Dave Vincent