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Winterfield's first project (400/4)
Bryanj:
No mate its frizzy haired geek!!
Winterfield:
I decided that the dressing table I was using as a workbench was inadequate (because it was). So I built myself a workbench, and tried some fancier joinery than I had before.
Not too long after completion I managed to drop most of a sump of old motor oil all over the top of this bench. No problem! Just unscrewed the tabletop and flipped it over :)
It was joined by some shelving to store all the spare parts, and a parts washer to take the top layer of gunk off.
Winterfield:
So, back to the bike.
Work split into two parts at this stage: getting the engine in the bike started, and attempting to unseize the stuck pistons in the spare engine.
After messing with the electrics, continuity tests, checking and sanding the points, I noticed that when I manually actuated the points I would get spark. This lead me to believe that the battery was shot and was not able to turn the starter and supply enough current to charge the coils. Someone with more knowledge might be able to confirm/deny the truth of this.
With a new battery, and with no headlight attached, there was enough juice to get it started. At first it would rev very high, then die. I suspect I hadn't tightened the carbs to the airbox, or manifold properly. I eventually got it to idle and was happy that it was a running engine.
https://youtu.be/C5RQ_t6lYfQ
Winterfield:
On to the spare engine. It had the head off, and had likely been sitting like that for some time. No info on why it was in that state, or why it had been taken out of the bike.
I wanted to see if I could get the pistons out, with the intention of stripping the engine down and rebuilding it to put back into the bike. It could have been totally minced inside, but I had a working engine so I didn't see I had much to lose.
First steps were to try and loosen the pistons by way of soaking them with penetrating oil. I wasn't sure which to use, so I thought I'd experiment and tried motor oil, Halfords penetrating oil, WD40, and machine oil. One for each cylinder.
Left it for a week or so, and hoped to see the oil levels drop as it made its way down past the piston. No noticeable change, and the crank would not turn. I didn't expect that would work, as this would of course require all of the pistons to be freed.
Someone recommended that I pour boiling motor oil (!) into the cylinders. The idea is that it heats the piston and sleeve, and while they're expanding/contracting at different rates, the oil makes it down past the pistons. No dice here though. Also tried some heat on the sleeves from a butane torch. I suspect that one of the issues with these approaches is the steel sleeves and the aluminium pistons just disperse the heat through the cylinder fins.
Winterfield:
I read that it is possible to get the barrels off if you split the cases, and then unbolt the big ends of the connecting rods. So onto the bench it goes. This is when I should have checked that the sump was emptied before the engine was removed from the bike. It wasn't.
Pictured here: the underside of the top half, with the connecting rod bolts showing. Note also the lovely new oiled bench top finish. If it seems like I'm going on about that, it's because I am. It still stings a bit to have made such a rookie mistake - no doubt one of many.
After getting the barrels off, I was able to extract the pistons. I didn't get any pics of this, but the process involved a small cylinder sized block of wood to protect the piston and sleeves, and a hammer. Some somewhat gentle persuasion and I managed to get the pistons out.
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