When you buy a 1983 Yamaha XJ650 for two hundred notes you don’t expect too much. Especially when it has been around the clock despatching. Two days after taking delivery of the shaft drive four disaster struck. There was this crunching noise running through the engine as we lurched through town. It went away for a moment then the motor locked up solid. By the time I'd grabbed the clutch, the 450lb hack had slewed to a halt.
Car drivers forced out of their reverie by this sudden retardation were not too amused. Horns blared and fists emerged out of side-windows. No-one rushed out to help me push the heap into the gutter. With an excess of corroded discs sticking on and massive clutch drag, this was no easy act. Not to mention that I’m the proverbial 9 stone weed who gets sand kicked into his face. The end result was that we cleared the road for annoyed car drivers by collapsing into a heap on the pavement.
Fortunately, I landed on top of the bike rather than it laying me out flat. Mind you, the third degree burns from the fuming engine did not exactly endear the beast to me. The gaggle of pedestrians who were displaced by the falling Yamaha were even less elated. Not one offered to help me pull the XJ upright. This had become quite important because fuel was streaming out of the petrol tank. With extreme effort I managed to right the Yamaha before it exploded. The good old AA eventually took us home.
After about two weeks my back had recovered sufficiently to allow me to stagger out of bed. Were it not for the fact that I was completely broke I would have pulped the bike into a million pieces. Some kind friends volunteered to pull the engine out and help me with the strip. I cringed every time one of them whacked a seized in screw with the hammer and chisel routine.
To cut short a long story, the problem was caused by a pattern oil filter breaking up. It may just have been that it had not been changed for years, but I made damn sure to stomp up for an OE filter after that experience. Bits of the filter had found their way into the gearbox. One of gears was missing teeth where it had seized on the wire mesh. Other bits of the filter were found bunging up various oilways. Luckily, the gearbox seizure occurred before the top end or crank had time to be seriously damaged.
Otherwise, the general condition of the engine was surprisingly good. It looked like the DR had been telling the truth when he said that he'd recently put in new cam and primary drive chains. The bores were heavily worn in places, the rings a bit gummed up and the camshafts scored. None of it was serious enough to warrant replacement. Anyway, a new filter and can of oil all but blew my budget out of the window.
A mate agreed to let me borrow the front end off his seized XJ650... mine was so far gone the handling went crazy above 65mph. Another mate, used to a devious Kawa H1 500 triple, reckoned it was much worse than his machine! This new front end had been completely refurbished 2500 miles ago. Once the engine was back in the frame, I found the motor ran as before except that third gear made some desperate noises. It was so fearsome that I always booted straight up from second to fourth.
Or tried to anyway. However good the box might've been when new, with 122000 miles done it was now horrible. It needed a really hefty boot to make it shift, more often than not finding a false neutral. The large amount of torque from the 653cc engine enabled the machine to run along in fourth for most of the time. Careful control of the throttle enabled the XJ to roll off from as little as 20mph. After a hard day’s riding I have been known to ferociously slip the clutch from a standstill in fourth. It was less hassle than trying to play games on the ever so tired box.
Fifth was dubious, because even when engaged there was a strong likelihood of it slipping out of gear. First gear had the reverse problem, it would often lock the gearbox up solid. The only way around that was to turn off the engine, rock the bike back and forth, using a hand on the gear lever to whack the bike back into neutral. Luckily, the bike could take off in second with no need to abuse the clutch.
This sounds like a pretty horrendous problem, but it didn’t intrude into my enjoyment half as much as the engine cutting out in the wet. The direct action of the shaft drive encouraged the back wheel to lock up when the engine went dead. As this, by its very nature, happened on wet roads some very frightening skids occurred. Although large and heavy, the XJ was surprisingly easy to control with its improved front end. The back featured relatively new Koni Dial-A-Rides, so no big problem there. Stability and flickability were of a level that I escaped any doses of tarmac fever.
In the 10 months I’ve owned the XJ I never did discover the reason why it kept cutting out. There seemed nothing inherently wrong with the electrical system. She always started rapidly on the electric boot and | did not even experience any blown bulbs. I tried coating the coils and HT leads with a silicone sealant, but the problem still persisted. Spraying everything with WD40 reduced the cutting out to about once a week rather than a couple of times a day.
This effect at least meant I never found riding the XJ boring. It was far too unpredictable a beast for that. The Yam wouldn’t pull more than the ton, which was about as fast as I'd feel like going on a machine of this mileage. My left hand always hovered over the clutch. When new the motor put out over 70 horses, but acceleration felt more like 45 to 50hp were available. Unfortunately, fuel did not match that prognosis. 30 to 35mpg was the norm, occasional mad blasts wrecking it further, 25mpg all too easily attained.
As the carbs needed balancing every 500 miles I suspect that they were badly worn, the main cause of the appalling economy. As the chassis became most temperamental on less than 3mm of tread, tyre life was also horrendous. Not much more than 5000 miles could be achieved on either Metz’s, Pirellis or Avons. The shaft drive often whined and lurched annoyingly, which was cured, more or less, after adding some oil to the near empty housing.
Finish isn’t worth talking about on such a well used and abused machine. Where I could, I touched it up with Hammerite. The degenerate appearance did provide the local rozzers with some mild amusement. They finally got fed up with trying to find a mechanical rather than a cosmetic fault. Over 18000 miles of thrashing the bike proved itself remarkably tough. Even the shims in the valve gear didn’t need any attention. They had already worn as much as they were going to wear and decided to settle down nicely.
Eventually, my mate had fixed his XJ650 engine, demanding that I give him back his front end. He wasn’t too amused to find that the calipers were sticking on and the pads out of life. In the meantime I had put stiffer springs in the original forks and cleaned up the old calipers. Braking was just about equal to the available performance. At least in the dry, wet weather was a different story. The front brake became like an on-off switch. Either massive braking force or nothing whatsoever. I was forced to use engine braking and the rear brake.
Not an altogether successful strategy, as thrashing down the box usually put the bike in a false neutral. Using the front brake in emergencies meant I had to fight a skidding front wheel. After a month of this self abuse my hair started to turn white! My hands were about as steady as the XJ's tickover. I kept annoying the local breakers by demanding calipers but most of them were in as sad a state as my own.
Salvation only came when my mate seized his engine again. Laugh? I almost pissed myself. Especially as he was so annoyed with the repeat performance he let me take the machine off his hands for a mere hundred notes. The cunning bugger took his nearly new tyres off first, mind, sticking some old Jap rubber on in their place. His chassis was in much better shape than mine, having only done 45000 miles. The obvious move was to put my engine and wheels in his frame.
That put the braking back to being predictable in the wet and improved the overall handling.
The cause of his engine seizure remains a big mystery. He didn’t thrash his machine, did regular services and knows a lot about engines. Both times the pistons have melted into the bores. I have stripped the engine right down, next time I have to pull my motor apart I will fit his gearbox internals. It would be very nice to have a full complement of gears.
That’s the state of play as I write this. I have a somewhat tired engine in a nice chassis. Until I bought the second bike I just figured on riding the Yamaha into the ground. Now I’ve got a mass of spares it has become an entirely different proposition.
Although XJ engines are not entirely lacking in problems, they seem to run for high mileages given a bit of care and attention. The damn thing still cuts out in the wet on occasion, which is my only serious complaint at the moment. The rest of the idiosyncrasies I can take as they come at me. I have a feeling I will get the damn beast past the 200000 mile mark!
Graham Jones