I always thought that the XBR500 was a neat bit of tackle but one never came up at the right price at the right time. Imagine my enthusiasm, then, when its sibling, the GB400, was on offer as a grey import. 8000 kilometres on the clock, immaculate condition and a mere £1500. No guarantee for that kind of dosh but the reassurance of a shining new MOT certificate and 12 months tax thrown in. Okay, I'll take it!
The GB400 looks just like what you'd expect a modern BSA or Norton to look like, if they were still in the business of making motorcycles. Neat, narrow, compact and light, its dimensions were less conspicuous than many a 125! The riding position was full of nostalgia. Clip-ons on the top of the forks, rear sets and a big chunk of a steel tank with cut-outs for my knees. It was as instinctively right as it was comfortable.
The motor spat into life without too much effort on the button, with the reassurance of a kickstart for back-up. Five minutes, or so, were needed for the thumper motor to warm up. Neglecting that would cause first gear to go home with a bang and the engine would try to conk out if ridden below 3000 revs. Once warmed up, though, everything was much smoother. 400cc being rather more suitable for a single than half a litre, there was markedly less vibration getting through, the depreciations of the balancer system leaving just the gentlest of impressions of a motor working away.
Acceleration was brisk rather than startling, just about able to keep up with a good CB400N or GS450. At 340lbs it was lighter than either of those bikes and was even able to keep up with the odd XBR, at least up to 80mph when it began to run out of puff. 100mph or even 105mph was possible under extreme abuse and favourable conditions. For most of the time 90mph was the most that could be reliably extracted.
To be honest, I was happy with the performance because the bike was quite delightful to run around on. It was a combination of the thumping torque that made the gearbox largely redundant, easy steering and, most importantly, feeling part of the machine rather than just perched atop it.
The only thing to annoy me was the Japanese rubber in the wet. Japan has torrential downpours all of its own, so there was no excuse for such poor tyres. It just turned to teflon on wet surfaces, allowing the lightweight machine to slide all over the shop. Worse still, the tyres would aquaplane at 60 to 70mph, the first time I've ever experienced that strange floating to oblivion sensation.
They had to go. Of course, the GB400 didn't exists on any companies' lists of bikes suitable for their tyres. A pair of Venoms were available in appropriate sizes and levered on to the alloy rims. These are old fashioned tyres in shape and compound, but then the GB's a kind of old fashioned bike, too. They stopped the wet weather madness, wore moderately (still not out after 12000 miles) and didn't limit cornering angles, although they would squirm around a bit. They ain't recommended by the manufacturer so if you fall off your insurance may be invalid!
The brakes were in line with the rest of the bike - ie usable and practical. A remarkably good rear drum that was an object lesson in how to design a back brake, and a single front disc that needed a manly right hand but had no hidden horrors ready to spit you off in return for a moment's inattention. After about six months the front brake went a touch spongy, Goodridge hose and new brake fluid sorted it out. Unfortunately, I spilt a little fluid over the paint which immediately bubbled, leaving a large scab. The finish had been beautiful, putting me into a really foul mood for the next month!
Some drops of fluid had also hit the engine casing, causing the lacquer to curl off and the alloy to go white. I had to take all the old lacquer off and paint on some new stuff......five days later that started to come off as well. I ended up giving the casing a polish every month which just about kept up with the corrosion.
The only other break out of corrosion occurred on the exhaust's collector. Backfiring started when holes appeared and didn't stop until I'd replaced the collector with a bit of old exhaust pipe. The downpipes are just starting to turn rusty as I write this (on a four year old bike). Honda are renown for their fine finishes, it's just a pity they don't make their exhausts out of stainless steel. I'm not sure if aftermarket XBR exhausts will fit or not.
The GB shares with the XBR (and even the FT500) a dodgy starter motor. The clutch seized up on mine. The resulting noise made me think that the main bearings were gone but, providentially, all that was needed to free it up were a few taps from my favourite hammer. The starter looks identical to the XBR500's so replacements shouldn't be impossible.
The other XBR fault, poor rockers and cam lobes hasn't reared its head for the simple reason that I haven't taken the cylinder head's cover off. The only maintenance I've done is change the contents of the oil tank every 3000 miles. I've always been of the persuasion that leaves well alone if it's running at all well. Either a naff gearbox (oil worn out) or poor economy (carbs or valves out of adjustment) give plenty of warning of an engine in need of attention.
Fuel was very good, much better than the XBR. A minimum of 60mpg with 75mpg possible on quiet country road riding. The only annoying consumable was the rear chain, a trait shared with the XBR, which wore out in 4000 to 5000 miles. There were some crunching noises at low revs as the chain wore out and it would ultimately turn the gearbox wicked. Admittedly, I always fitted the cheapest chain I could find and a top quality O-ring job might go for twice that. On such a practical piece of iron full chain enclosure would've been good but at least there were gaiters on the front forks.
The only time the handling went a little funny was when I went camping. There was so much junk tied down on the seat that there was barely space for me to sit. It was just as well that I didn't have a pot-belly. The front end felt dangerously light, coming close to a wheelie for the first time in its life. After half an hour I was used to it, could rumble along at a reasonable 80mph without too much weaving.
No, what caught me out was a bit of low speed manoeuvring in a narrow country lane. I was trying to turn around but the bike just suddenly slammed down on the tarmac, catching my ankle on the engine. Normally, I'd wear boots but as it was the high summer I was in trainers. The burn went right down to the bone. The pain was so intense that I flipped the bike off me so that it bounced on its other side, breaking another set of levers and indicators. I had to bind my ankle with a torn up shirt and ride forty miles to the nearest hospital, cursing and swearing all the way.
That was the only bad moment in 12,500 miles of riding and not really the bike's fault. I think it's better than the XBR and most other singles on the market. It has more character and quality than middleweight twins with similar performance. It's pretty cheap to run, fun to ride and nice to look at. I can recommend it for any type of riding.
James Dugley