Saturday, 18 June 2011

Kawasaki GPz400


I really wanted a Kawasaki GPz550, as it had a useful blend of performance, economy, handling and looks. There were plenty available for under a grand but all the ones I saw had the telltale signs of massive abuse and owner neglect. Obvious crash damage half-heartedly disguised went down no better than the 50-80,000 miles these bikes sported. Sure, the engine's one tough old mother, but not that tough! Not when most of the owners looked speed addled, were disinclined to discuss minor matters like oil changes.

A mate told me about a GPz400 for sale by a mature rider over the other side of Southampton, so we went to have a look. Mature was an understatement, the guy looked about eighty. The little Kawasaki stood there all polished up in its glory, the only reason for the sale of the 19000 miler was the owner didn't like the need to rev everywhere and he couldn't understand why modern bikes needed six gears. I didn't have the heart to try to bargain down the 800 notes he wanted, already too much like taking candy off a baby.

The ride home was full of furious fun as we took a fifty mile detour and my mate was a complete nutter when faced with an open bit of road. The Kawasaki four screamed into the red in an effort to keep up with the XJ600. At about eleven grand the engine began to grind out a little bit of vibration but nothing to compare with what I had to put up with from the pillion pegs of an old warhorse like the XJ.

Power punched in moderately at about 6000rpm but came on really strong 2000 revs later and didn't stop producing until well into the red. On that first ride I touched 125mph which effectively proved to be its top speed - there just wasn't the power there to push the bike any faster. Torque wasn't really a concept that the engine understood, needing loads of work on the gearbox to keep the speed up. The slightest incline or sniff of wind had me going bananas on the throttle and gearbox.

Initial impressions were that the gearbox was quite smooth and precise but as the engine heated up the change went a bit clunky and a couple of times I even missed an engagement. The rev counter went deep into the red and the poor old engine wailed away like it was going to explode into a million pieces. Oddly, after a couple of days the problem went away, I must've become used to the box's ways!

Less easy to get a grip on was the handling. The bike was a good fit, the bars where they were supposed to be on a bike of this performance potential, but it didn't really want to stay on the straight and narrow when the wick was turned up. I had a death-grip on the bars by the time the ton was passed and was told, after I'd zoomed past matey on the XJ, that the back wheel was wriggling around like its spindle was loose.

First job was to tighten that up. Brute force applied but it had no real effect other than to need a bash with the hammer to get it undone when I wanted to, later, adjust the chain. I went over the rest of the chassis with the spanner - it really felt loose enough to indicate that something was seriously amiss - but could not find anything off. It wasn't bad up to about 80mph but who wants to ride at such slow velocities? - I wouldn't get to our destination on the same day as my friends! As it was, I was but barely able to keep up with them on their much bigger tackle.

The tyres were newish Metz's but turned out to have 5psi too much pressure in them. Aha, thought I, solved it, the bike immediately feeling much more secure and well planted on the road. The first time I took her over 90mph I discovered how wrong I was - the bloody thing twitched its bars, went into a major league speed wobble. By about half a millimetre I missed the side of the car I was trying to overtake - the poor old cager's eyes almost popped right out of his head at this unlikely assault on his pleasant summer day's drive!

I pulled into the first gas station and pumped in ten psi to see what would go down. Some joker had once put about 100psi into someone's tyres, just to see what would happen. The guy rode his suddenly wired Z1 straight into a field and promptly fell off, doing in his back in the process. Knowing that, I took it very gently but still found the bike wanting to slide all over the place though it began to quiet down once past 70mph and the thing was amazingly stable at the ton!

Something wrong with the tyres. Looking very closely, there was some crazing in the sidewalls, indicating they were pretty old. A set of Avons was found in the breakers who even agreed to fit them. At forty notes a bargain. He left some deep marks in the alloy rims and covered a disc in dog shit! Obviously a mechanic of the old school. I refrained from acquiescing to his demand to take the bike to him for servicing in the future.

On the tarmac, the bike felt weird below 50mph, as if only a small band of rubber was actually in contact with the road. I pulled over, let some air out of the tyres and gave it another go. This time it wasn't bad and I was soon into a bit of speed testing. There was a heavy weave at the ton-ten which threatened to go the speed wobble route again.

I tried a bit more tyre pressure adjustment - 29psi in the front and 31psi in the rear suited the bike best but it still felt a bit dodgy at maximum speeds. I then concluded that the steering head and swinging arm bearings needed replacing. The suspension was on the firm side, probably not original, the bearings the only thing I could think of. A mechanic friend offered to knock in some taper-rollers in the steering head for forty notes and leave the swinging arm bearings for later, only do them if it was really necessary.

What a transformation. Felt like I'd been handed a factory fresh motorcycle! The bike didn't give a hint of a weave even when flat out! With the new stability it was throttle to stop, break the 125mph barrier, all the time - I soon became used to the secondary vibes that ground out through the pegs and petrol tank! Took about an hour for my hands to go so dead I couldn't operate the switches, but the GPz was so stable that I could happily loosen my grip on the bars to the bare minimum, which helped a lot.

Overall comfort, apart from the vibes, was fine - the bars, pegs and half fairing conspiring to leave me in a pretty natural stance. The seat seemed factory fresh in its firmness, took about three hours before I started to squirm around - my mates on flasher, more sporting bikes, were often in agony after half an hour. It often surprised me that guys on Yam FZR's, and the like, would reach a destination a couple of hundred miles away no faster than myself - even the hotter riders were condemned to slower speeds than their bikes were actually capable of by traffic, curving roads and loitering plod.

Even when mercilessly caned the GPz turned in 50mpg, often doing as much as 70mpg when used for moderately fast motorway work or around town. Consumables were similarly long-lived and much cheaper than for the posh replicas. The only area where my mindless throttle abuse took an immediate toll was on oil consumption - surprisingly heavy at about a 100 miles a half litre, dead easy to run the sump nearly dry if I didn't pay attention.

Some really long runs, up and down the country, really pushed things - it's a pretty enervating bike to ride all day long, ended up at the close of the trip with a serious case of the shakes, but even that didn't stop me breaking through the 1000 mile barrier a couple of times - much to the amazement of my mates. The clutch fried after such abuse, became a real bastard in town as the gearbox suddenly had twenty neutrals and three working ratios! Amazingly, give the bike an hour to cool down and all worked well again.

Considering that in 30,000 miles all I did was 2000 mile oil changes and the odd filter swap, I think I got away with murder. Especially as I was able to sell the bike for a 1000 notes - the finish wasn't half bad, just needing some patching up of the chassis and a complete paint job on the swinging arm which was covered in rust, thanks to an O-ring chain conversion that needed little attention and therefore didn't generate any excess (protective) oil.

Even the triple disc brakes, notorious in other Kawasaki models for quick rotting, didn't need much attention. I did the fluid and pads after about 13000 miles of abuse and they were ready for replacement again by the time the bike was sold. The braking required a fair degree of muscle but was well up to the machine's performance. I only had to watch my step in the wet when they could display an annoying lag and suddenly grab on - a quick way to bash the tarmac into submission.

The bike's obviously a bit limited by its capacity and lack of torque, but I can't really find it within myself to complain. After I sorted the initial handling hassles, it was kicks all the way and an amazing amount of speed-addled fun!

Dick Williams