Thursday, 31 January 2013

More on the C90 - fun and games with the stand!

The C90 work continues, and today we got the old stand off. It was rusted to the pin around which it should rotate, so it had to come off so a new, modified (to prevent it happening again) pin can be fitted. But first, how do you remove the stand spring? It's very strong!


We tried pliers, then a spring puller, but it wasn't going to shift. So we used this:


The rope goes around my waist, I lean back, and the spring hook stretches the spring enough to free it from its peg.

But how do you remove the pin from the stand when it's rusted in solid?
We tried penetrating oil and a big hammer, but it wouldn't budge. So we resorted to the angle grinder and cut the pin at both ends between the bike's frame and the stand.

That got the stand off the bike, but left us with most of the pin still rusted into the stand. So we took it to a friend who has a garage business and a hydraulic press and tried to press the pin out of the stand. It wouldn't budge.

Next, we put the stand in the vice and hack sawed a slot in the top, then took it back to the press. At first, it wouldn't budge. But at 6,500 lbs pressure, there was a bang and it moved - about 1/4 of an inch! With progressively longer bolts to push on the end of the pin in the press, we continued with the 'press' treatment. Each time there was a 'bang' and a cloud of red dust as the pin gradually got driven out of the stand. It took about five such 'presses' before it finally came all the way out. These things don't just drop out, even when you cut the stand! Here are the bits, with the hack-sawed stand:


How do you prevent the same thing happening again? Indeed, how do you prevent the new pin rotating in the frame and wearing the holes in the frame (as mine was, which is why it had to be rectified) even if it's removed and re-greased frequently? Malcolm, a friend, did this:


The new pin has been drilled down its centre then cross-drilled to allow grease to be pumped in through a grease nipple at the end of the stand pin where the split pin normally goes through. Note the grease nipple has to be tapped into the end of the pin PAST the split pin holes, or else the grease would simply squirt out there.

At the 'head' end of the pin (the brake pedal end of it) he welded a tang which is stepped to rest on top of the brake pedal stop. This will be drilled and tapped so the tang is firmly bolted to the brake pedal stop. This both prevents the pin from rotating, and keeps it in place in the absence of a split pin at the other end.

Now we just have to weld-up the stand where it was hack sawn, clean up the stand tube internally, grease the pin, insert it, drill the tang and drill and tap the brake pedal stop, and bolt the tang to the pedal stop. Finally we'll replace the spring.

Then I’ll re-fit the exhaust, put oil in the bike, kick it over a few times to get the oil circulated (we’ve changed a valve and the clutch plates and TimeSerted the plug threads in the head). Then see if it starts! And doesn’t leak! Fingers cossed!


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