Sunday, 31 July 2016

Kawasaki GPz305

The Kawasaki EX305A1 (read GPz) was launched in 1983 and is basically an over-bored version of the ER250 Scorpion. The 250 engine first appeared in 1979, so is by now well tried and proved (cue for hundreds of disgruntled owners to write in - Ed). The last 250 boasted a belt drive which the 305 adopted in 1984 along with some other minor changes including a new clutch mechanism (similar to the GT550). The latter employed to stop the oil seeping out of the old mechanism when an O—ring went, although lots of instant gasket would stop the flow.

Tyre choice makes a tremendous difference to the way the bike performs, particularly to the flickability through the corners. Pirelli Phantoms, which were expected to be good, were thrown away before they were worn out. Good all-round tyres were Metzeler ME77s. Roadrunners last a long time (15000 miles on the front) but allow the front wheel to slide a little in the wet. ME77s last for 3-5000 miles...

Ordinary oil needs changing every 1000 miles along with the filter, but (and I don’t work for them) Shell’s Gemini oil appears to last anywhere between 1500 and 2000 miles without any ill effects. Oil consumption is negligible even with 30,000 miles on the clock.

Spark plug consumption is in two stroke country, unless they’re changed every 4000 miles high speed performance disappears. Chains last for around eight thousand miles, while the £70 belts can last as little as 4000 miles before teeth start disappearing — once one has gone it's not long before they all snap off and the belt ends up looking like a rubber band. The most that I’ve heard a belt doing is 15000 miles and, at least, you don’t have to change the sprockets.

Another quick wear area is the Uni-trak, I’ve just spent £80 on bushes and sleeves after one of the linkages snapped - okay I didn’t grease it, but it’s not nice having the rear suspension collapse whilst you’re on the bike. It really needs to be taken apart and greased twice a year.

It isn’t difficult to touch the pegs down even with the suspension jacked up to maximum. Travelling two-up can easily result in the bottom of the silencer wearing out (Motads are even lower) or the side-stand digging holes out of the tarmac (this takes the stand out and activates the ignition cut-out switch - but this should be bypassed, anyway, cos they always cause the engine to misfire).

At first, I wasn’t impressed by the lack of a kickstart, but the Kawa has always rumbled into life at the first touch of the button even in the depths of winter. It needs full choke to start, but after a few hundred yards it ban be turned fully off. Vibes arrive at 5500rpm but quickly disappear by the time the real power starts arriving at 7000rpm.

Maximum torque arrives at 8500rpm, equal to atop speed of 100mph. A Motad exhaust makes a big difference to the bike’s mid-range power but doesn’t increase the top speed.

The brakes must be about the best for this class of bike, the double front discs make the forks "brake dance," a brown trouser effect. Under normal conditions, however, there’s plenty of feel with only two-fingered pressure required. The rear brake is not in the same league, with no feel and not much power. I feel that a disc at the back would be much better. Front pads last for 8 to 10 thou and rear shoes a little bit longer.

The biggest plus for the bike is its amazing fuel economy — I get between 70 and 80mpg running to and from work at a constant 70mph. At slower speeds, with a less twitchy right hand, it’s possible (with great boredom but I did try it out) to creep into the nineties but I’ve never broken through the 100mpg barrier, but then it isn’t a C50, is it? This must make it the ideal choice for commuters, especially as it can be run on lead-free fuel with no noticeable ill effects (I’m not a conservationist, the stuff is cheaper).

The riding position is good but expect an aching backside after as little as fifty miles and the pillion’s perch is even less comfortable. The bikini fairing protects the top half of the rider to some extent, but if you‘re more than 5' 10" tall expect the screen to blast air straight into your face. As I’m over six feet tall, a 2" flip up screen addition was a good investment. The controls all worked quite well, although the mirrors start to blur after 7000rpm and just become worse as the revs increase, which is a little licence-endangering if you’ve an ill restrained right wrist. The fuel gauge is helpful, although It doesn’t start working for the first fifty miles on a full tank, it does register empty when there’s a useful fifty miles worth of petrol left.

Overall, I find it an excellent bike (well, what do you expect from an owner) but there do seem to be good and bad uns. Amongst the latter was a camshaft that went at 12,500 miles (lack of oil changes I’d guess). Others have a disturbing tendency to cut out in the wet because of the brilliantly designed front mudguard that gives the engine a bath in the rain. The company that produces WD40 must be very grateful to Kawasaki as emptying a can on the electrics and taping all the connections to the CDI unit seems to cure any electrical failure.

There are reports of the top end prematurely wearing, but I suspect that this only happens if oil and filter changes are neglected. Both the bikes I’ve owned have had louder than expected top ends for thousands of miles but with no self destruction... so far.

Given that the engine is hardly any bigger than a 250 and its design is nothing more complex than something Honda might have released in the mid-sixties - a mere two valves per cylinder, one camshaft, an 180 degree crankshaft and no balance shafts - the amount of performance available combined with the excellent economy is pretty damn good, and puts rival and far more complex twins to shame.

One bad, really more annoying than anything else, problem is that endemic to the breed is a continual smear of oil from midway up the barrels even with a new head gasket and the nuts tightened down way beyond the recommended settings. There seems no cure to this problem, short of Aralditing the gasket to head and cylinder.

On out and out performance, it obviously can’t keep up with the 350 two strokes, like a Yamaha YPVS, although, somewhat surprisingly (you should see the look on their faces) it will keep up to around 60mph before it gets blown into the weeds. Unfortunately, riding it like a crazed lunatic helps not one jot, as most LC owners are crazed lunatics in their own right. It would be interesting to see if the much better fuel economy of the GPz would let it catch up over a long distance as it wouldn’t have to stop to load up on fuel so often.

Spares are not particularly cheap nor very readily available from breakers - trying to get side panels from a breaker is like trying to get blood out of a stone.

It’s no good asking me if I’d buy another, as I'm already on my second... I suppose a GPZ500 twin would be the next logical step.

Alastair Scott

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