Saturday, 11 February 2012

Kawasaki GPz400

The first thing that hit me was the Kawasaki lime green. The owner had extended the theme to the seat cover, wheels and frame. Pass the sick bucket. On the other hand, the exhaust, brakes and engine paint looked brand new despite the mileometer reading 19000 miles. Once upon a time, in 1982, it was a Jap market model GPz400. The current owner was the second UK based pilot, had kept it for half a year. Selling to buy a CBR400.

Test ride, reared up on the back wheel so the motor must be okay. Yep, a nice one! I'll have it for £1600. A bit of haggling over the optimistic £1995 price, mine for £1650 cash, no questions asked and no come back. Good luck with the CBR, mate, you'll need it!

The GPz400 was a bit different to the UK's short-lived GP550, the precursor of the famous if not fabulous GPz550. Where our GP550 had twin shocks, the little 400 had the well known and regarded Uni-trak back end. This was pretty typical even back then, the Jap's getting the hot stuff in their 400's before we had them in our bigger bikes.

Curiously, the 400 weighs the same as the 550 at 400lbs, so it looks like the 550 was derived from the 400. Good, that means the 400 is in all probability very tough. The 400 was styled a bit like the Eddie Lawson replica and I welcomed the cut-down seat as it got both my feet on the floor and made me feel much more a part of the machine.

The total lime green paint job had me the laughing stock of our bike club so I had to sort that out pronto. I hand painted the frame (with the engine still in it) and wheels black, then had the seat recovered. That was a relief to the eyeballs, with just the tank, panels and front guard lime green it didn't look half bad. Often mistaken for the 1100 Lawson replica after I dumped the 400 marking on the sidepanels!

The 400 makes 48 horses at 10,500rpm, which is okay but not stunning. Where its lack of cubes shows up is in the lack of power below 7000rpm. The bike feels best at 8000 to 9000 revs, although it will spin to 12000rpm! The usual six gears and light clutch but the throttle was rather heavy and imprecise until a new cable was fitted (well, not new, but a used GPz550 item).

Tearing around on the little Kawasaki I was pretty pleased with myself until the back end went all loose. Bloody Uni-trak linkages, I swore to myself. Nope, even worse than that, the back wheel's hub was cracking up. Now, it was a favourite pastime of my mates and I to whizz down to the local ped precinct, charge up on to the pavement on one wheel.

Meant that the back wheel whacked into six inches of pavement at about 40mph! I wasn't the only one to suffer a cracked cast back wheel, though those with spoked wheels escaped without serious expense.

A GPz550 wheel was persuaded in, though it had a fatter Avon tyre which didn't really match the front Dunlop. Even with stock wheels handling wasn't exceptional, mostly down to the way the suspension would bottom out once the road became bumpy. It often wobbled around bends in near out of control mode but it did, more or less, stay on the required line and I soon learnt that the best thing to do was just sit there with a loose grip on the bars. Fight it, and it'd bite back in a big way.

With the mismatched tyres it was prone to high speed weaves and wobbles, the severity depending on the state of the road and the speedo. Top speed was an indicated 120mph, but that was flat out, curled around the machine, and it could lose 20mph if there was a steep hill or strong wind.

The bike was amazingly susceptible to sidewinds for some reason. As a naked bike I didn't expect it to be comfortable at speed, so I was pleasantly surprised to find I could hold 90mph for as long as the 18 litre tank lasted (usually over 200 miles). The sidewinds, though, would grab hold of the machine, shake it all over the shop and at times almost cause the thing to run off the road.

It was better to hammer along at 80 to 100mph, lean slightly into the sidewind than to cop out by hopping along at 20mph, full of fear and loathing. The bike was much smoother than the 550, at least until the latter was held in rubber mounts in later models. The 400 needed no such sophistication, as it was naturally devoid of secondary vibes for most of the rev range.

A bit gruff below 3000 revs and some fierce resonance beyond 11000 revs, when if truth be told the power had more or less run out and it was only a matter of adventure and ego that made me screw it so hard. You know, my bike can do 15000 revs without blowing up, so there!

How did its various components weld together? Was it more than the sum of its parts? Probably not. There was a dysfunction between the high revving, hard charging motor and the rather soft chassis; so ill-matched that it suggested the bike was used for most of the time as a pose rather than speed tool!

The same could be said for the triple discs. Probably the same spec as the 550's, they were fierce things that mucked up the soggy suspension to the extent that I had to go easy on them. The few times I had to brake really harshly to avoid immolation on various cages, the front end was left nodding away to itself, thoroughly bemused by the force of the sudden violence.

In the end, I became so weary of the suspension's machinations that I decided an upgrade was in order. Heavy-duty springs meant for a CBX550 and a GPz550 shock were fitted. It was at this point I discovered that the steering head bearings were pitted and the Uni-trak linkages a bit loose. More expense. A brand new set of Michelins was added to the shopping list.

The end result was a tight, taut chassis that reacted much better to my fevered inputs. The only limit was the stock exhaust which then ground into the tarmac when I took the tyres to the edge of their treads. It was still a bit squirmy at speed, with the odd wallow coming in above the ton. The front forks were spindly, so I thought I'd bung on a brace and steering damper.

The former helped but the latter made her speed wobble at 110mph and was ripped off very rapidly. The daft leading link axle on the forks didn't help, the ultimate solution would've been to put a GPz750 front end on the bike but most of my riding was under 100mph when the bike was now fine, so it wasn't worth the hassle and expense as I just knew nothing would match up.

Touring was good fun as comfort was excellent. The useful range meant I could keep ahead of faster bikes which needed to stop twice as many times. On the open road, despite the use of high revs, fuel was pretty good, usually around 65mpg. For sure, ton plus running got that down to 50mpg, but most of my mates (on 550's and 600's) were doing 30 to 40mpg at similar speeds. So I was laughing, wasn't I?

Well, you know how it is. The day's sunny, the bike's running better than ever before and all's well with the world. You think, this is too good to be true. And a few moments later the back wheel bearings (on the expensive replacement wheel, guaranteed for as long as it takes you to get out of the breakers...) start clacking. Not a good idea to ride any distance with shot wheel bearings, not if you want to live!

We pulled into Leeds, found a bearing factor and swapped the bearings. Sounds dead easy, right? Wrong! The bearings had corroded into the casing and needed whacking with a chisel and lump-hammer; only thing was we only had a wimpy metal hammer and a socket wrench that kept slipping, the hammer trying to break my fingers! Ouch! Two hours of pain and tears finally did the trick.

By then it was dark. I don't know what the Jap's do in the dark but they certainly don't ride motorcycles down unlit country roads. The glow-worm of a front light was something out of the sixties...much improved by running an independent earth wire from light to battery but still nowhere near modern standards. The switches were also well worn, rather fiddly.

Minor quibbles but annoying nonetheless. I could've fixed them with non-standard stuff but I'd already spent a fair bit on essential improvements. Kept the bike for two years and 13000 miles - I don't usually ride much in the winter - without doing much to the mill other than thrashing it. Sold the bike for £1450, so not much of a loss and I could've held out for more had not I been offered an XS400 for a thousand notes that was in perfect nick (see later).

With 32000 miles on the clock, the finish was a bit tatty, the top end was just beginning to rattle (almost certainly the camchain, as they can be short-lived on the 550) and the electronic ignition was about due for replacement, though no signs of that yet - they just don't last that well (again, on the 550, but it's all the same junk...)

There are quite a few Kawasaki 400 four models, as well as that well known sluggard, the UK model Z400. The GPz400's about the best of them and not bad value at £1350 to £1750. Not worth paying more and the cheaper ones are well worn. Fun and frugal, as the UMG likes to say!

Pete Maine