It all began when some moron nicked my much modded CB900F, a great old bruiser of a bike that with a few minor mods topped 140mph. I had to get some new wheels fast and my cousin had a very nice CBX1000 he was reluctantly trying to sell. Only 11000 miles and never been stripped down or even seriously thrashed. Six cylinders, 24 valves, DOHC's and even two camchains - pretty much a CB900F with an extra couple of cylinders added on. Classic styling, upgraded suspension and brakes, plus a shining paint job that made the bike look better than when it rolled out of the factory.
The only negative factor was an exhaust system that was rapidly rusting away, though it gave the six cylinder mill a gorgeous snarl and backfired like a mortar going off on the overrun. Fun, in other words! Two and a half grand changed hands and the venerable steed was mine. After the vibratory, bull-like 900 four it was supremely civilized, lacking totally the sheer blood and guts feeling of the four.
Despite its width and size it was actually easier handling than the four, felt a whole lot safer. That's not a hard achievement as the CB had an heart of darkness that wanted to rule when speed was involved. Despite claiming a hundred horses, actual acceleration was down on the four, those 600lbs always needing a lot of effort to overcome to get the six running really hot. The bike was also deficient in torque, needing quite a lot of cog swapping to keep a ton-plus momentum going.
Putting 135mph on the clock required extreme effort, though the bike was much more stable than the four and didn't vibrate at all. The riding position was really good, too, despite (the bike) being naked I was well braced against the roaring gale and could hold more than a ton for half an hour without feeling like I was about to expire. The seat had non-standard foam and was about as comfy as it gets.
Ridden thus my major complaint was rapid consumable demise - fuel about 25mpg, half a sump of oil gone west in 200 miles and tyre life of less than 3000 miles! Ridden at gentler velocities, fuel improved to 40mpg, oil consumption was negligible and tyres lasted a couple of thousand miles longer. An hour shuffling through Central London - the bike too heavy and wide to really go for the traffic gaps - fried the clutch which in turn caused the gearbox to clunk and grind away like the selectors were shot. Use the bike just in town, water condenses in the oil after a mere 500 miles, so needs to be changed as water isn't renown for its lubricating properties.
After about 5700 miles of fun filled, and generally pleasurable, riding, the silencers were hanging on by mere shards of metal, both falling off when given a good kicking. Riding on just the down-pipes produced a glorious din, but such a loud one that my eardrums were soon rattling around in my helmet! God knows what the ped's thought! The local breaker had some likely looking silencers and welded them on whilst I waited.
The engine had a massive 3000-6000rpm flat spot sans silencers and the replacement silencers narrowed that down to 3500-4000rpm - the engine stuttered, felt like it was going to conk out unless I feathered the clutch and walloped the throttle open. Then it would leap forwards, trying to jerk my arms out of their sockets. Alas, the refurbished exhaust system removed the previous air leaks and the marvellous mortar effect on the overrun was a thing of the past, though it still made a spine tingling noise.
These various exhaust permutations, along with my neglect of valve clearances (never did them on the CB either and that ran like clockwork), led to some smoke on the overrun with about 18000 miles on the clock. I saw it in the mirrors the first time, nearly rode into the back of a lorry when I swivelled around to see what was going down. In no time at all, the engine started smoking when started up and then progressed to a stroker-like pall for most of the time.
Lean running had led to overheating which had fried the exhaust valves. Being the world's worst mechanic, and having read about the problems in reassembling CBX motors in the UMG, I wasn't too keen to sort this out. Luckily, the insurance money on the CB900F turned up at the right moment and the local mechanic was consulted. He's not as bad as some and even let me watch him take the top end down - it's a complicated bastard, right enough. He was able to regrind the valve seats and get the clearances right on - Honda parts for this bike are extortionately priced and I was happy not to have to cough up for any. An afternoon's work and 130 notes, I was back on the road - gotta be the bargain of the year as the flash dealers charge more than that for a service!
I kept the bike running to 20,000 miles, but didn't really thrash the balls off it as I was aware of its reputation for blowing up big time once it'd been rebuilt. Happy enough to sell it for what I'd originally paid - it even went to a good home, some born again biker who only wanted a bike for mild weekend outings. Overall, not really a speed tool but an interesting ride with a very distinctive character. Just avoid bikes that have had rebuilds and you'll probably have an enjoyable experience.
Gary Holmes