For the good lord said unto them... "Tell me what it is you want."
And the fools they cried, "We want power. Great power, over people."
But the wise, more importantly, asked of power from a different source. A device that could invoke feelings like no other. A mechanical device, designed by the hands and minds of humans... an engine. An engine that could deliver oodles of power from low revs, and induce wheelies at the slightest provocation. And the diligent were patient, and they duly received.
Four-stroke singles. Word.
Unheard horsepower from a mid-sized single is a great feat. For years they were dull, docile, heavy lumps that were dependable but, essentially, boring. Then they got quick, lightweight, scared the shit out of us, but were slightly unreliable. Because great power comes at great expense...
In time though, we got it all. Including 10,000km service intervals from a single cylinder midsize, pushing out around 66BHP. Stone the crows cobber, I think we're onto something.
The 690 SMC-R.
With great power comes great responsibility.
Boys, boys, boys...
Why do we hype everything up? What's with the banter? The underhand tactic of knocking self-confidence?
As long as there's been racing, riders have been looking over at someone's front wheel, looking up at their opponent and tutting. Anything to put an air of doubt into someone's mind and gain an advantage. And, depending on the mental strength of the other person, it's worked more than once.
But I was looking forward to this day for more than one reason. It was a chance to play with the 600RR on a track that was almost designed for it. Sharp, off-camber corners make big power a pain in the 'arris. The little Honda should be in its element. Easy to turn, easy to stop, and easy to get on the power.
The heatwave continues in Queensland and today will be tough. I'm taking my old leathers because the sweat is going to be pouring.
There's a certain lack of damping on this bike. The rear shock
is knackered, along with its bushes; but the forks, although good in appearance, were out of sync. The one seemed fine - pushed down easily and returned slowly, spot on. The other felt like it had no oil
.
So, first things first, whip the caps off and drain them.
They don't always unscrew as easily as this. I cheated - I'd already undone them with an airgun. If you're struggling to loosen them, fit them back into the yokes (triple clamps) and tighten the lower section. Leave the top yoke loose and you should now be able to undo the fork top nut.
Fork top nut out to reveal a plastic spacer. Not sure if this is genuine or not. Seems like a long spacer or a short spring! Anyway, both forks had oil in them so obviously that's not the problem.
Out with the spring, then a 6mm Allen key to remove the bottom bolt.
Then we can remove the damper assembly with the stanchion. The aluminium collar on the end of the damper tube just slides off, and the damper rod itself can be dropped out through the opposite end of the stanchion.
And finally, we see the problem, or not. The plastic "piston ring" is missing from the sleeve, allowing the oil to bypass, but KTM only list one. It should fit into the groove on the white plastic section at the end of the damper rod, but maybe only one leg needs it. We're going to get hold of another piston ring and fit it to see how it performs.
From what I can gather online, 110 ml of oil per fork is required and, by the feel of the other one, it's just the job.
There we have the basic, conventional fork stripped down. Very easy to work on and diagnose so don't be afraid to get stuck in.
Sorry for the blurriness of some of the photos, that particular photographer has now been sacked!
Another project, but not mine. This little racer belongs to Billy and the little KTM was having a few issues. It wouldn't run for long and, when it did, it would barely pull itself along. A quick try in the garage and it was obvious the clutch was slipping. So that's part of the problem. The running problem I already had a clue about; apparently she was drinking the gearbox oil - main bearings and seals!
Seat, tank and air cleaner out of the way, next was the pipe. Two-stroke motocrossers are so easy!
Off with the stator cover to reveal the oil pump drive - previously disconnected on this bike, and a quick feel for play in the crankshaft told me it needed main bearings. Grab the end of the crankshaft and try to pull it up and down, if you can feel play, the bearings are worn. Time to take off the cylinder head and whip out the engine.
The big and small end bearings have a fair amount of play - it's a wonder it sounded as good as it did when it was running. It's a fairly new piston, but I think we might need a new gudgeon pin as well as a connecting rod kit. Oh well, keep going and clutch cover off.
Not much left on the clutch linings - that'll explain the lack of drive. Not much in the way of gearbox either, simplicity itself! Need a puller for the clutch centre. Time for some fabrication.
The perfect washer. Couple of holes, refit the clutch centre-nut and job's a job!
Yes, they've worn very thin - the clutch drum is also worn, but hopefully not beyond spec. The shoes can be shimmed if need be, so let's hope it can be sorted. The new puller can be used on the rotor too - that'll ding dang do for me.
The taper broke with relative ease. This job is going well so far. Time to split the cases.
And there we have the gearbox oil that was being sucked through the seal and mullered bearing!
Time for the blowlamp to warm the cases. Get it to a temperature where your saliva spits back and the bearings should drop out. Gentlemen, spit on your engine (ladies get a cup of water).
Time to whip the piston off. I would have taken it off earlier but the circlips had been put in the wrong place making it harder to get them out. Cheers Pat!
Never mind, with the conrod held in the vice, the piston was soon off. Quick look over, smooth off the rough edges and clean the crown. Sorted.
So we need a crank rebuild, a gudgeon pin, four new bearings (crank and countershaft), three new seals, clutch shoes and a gasket set. Then we start on the chassis.
