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My CB550 K3 Restore Project
Bryanj:
Welcome, you picked the most unloved 550 model there but when sorted and used regularly(pd carbs are a shite) they are really nice and yes just a tad lighter than the GL
heli_madken:
Thanks for the warm welcome everyone,
--- Quote from: Bryanj on June 21, 2020, 07:05:11 PM ---Welcome, you picked the most unloved 550 model there but when sorted and used regularly(pd carbs are a shite) they are really nice and yes just a tad lighter than the GL
--- End quote ---
Yeah, bike was registered in July 77, by that time the promise of 'Super Sports', 'F' models had come along, I actually bought a 400 four Super Sport a month later in August which I loved and I remember thinking how much more modern the 4 in to 1 exhaust was. So it must have been a very 'special' person to ignore all the modern trends and buy this bike. Probably an older citizen which of course I am now. And the funny thing is I love the 4 into 4 exhaust this bike has now so go figure!
And yes the PD carbs dont get a good write up, I would probably like to change them. But having lived through lots of pain servicing the GL 755A carbs until I got them right they are by comparison very simple.
Got as far as removing the valve gear/camshaft cover today (I love taking stuff apart). Everything looks kind of ok to these relatively untrained eyes with the odd exception.
Not a great start, I sprayed Plus Gas on everything over the last two weeks but I guess on these longer bolts it isnt going to penetrate that far -
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The remainder should not be too hard to remove-
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Rocker pads look ok as do cam lobes and there is no movement on the shafts, plenty of clean looking oil everywhere so oil supply is good -
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Worst thing is this, I can feel it with my fingernail and there is a witness mark on the cam journal, not sure how I am going to deal with this yet any ideas? -
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Cant see how something could have got to that position whilst the engine was running so I think its been there on assembly which means that someone has been into at least the top end of this motor before I think.
I can lift a link on the cam chain about 5mm so the chain feels pretty loose, is this normal?-
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Tomorrow I will remove the head and see what other challenges are waiting
Bryanj:
Looks like a snapped 6mm screw to me Ken
K2-K6:
Welcome to the forum.
The cam bearing looks as if it has a casting inclusion from original manufacturer, with the fault "picked up" by their machining.
It's probably not going to affect it in any way now so safe to leave it alone. Traditional way of dealing with it would be engineering "scraping" in which a curved riffler file is ground to a compound curve metal chisel and then used to plane the surface back locally to remove the high spot.
Cam chain, I'd say is knackered if it's 5mm at centre of cam sprocket, and most likely the primary chain too. You might as well change both if you are stripping it. It's well worth while as they are intrinsically linked to a sweet running engine.
Looks pretty good in there otherwise from first glance.
K2-K6:
"And yes the PD carbs dont get a good write up, I would probably like to change them. But having lived through lots of pain servicing the GL 755A carbs until I got them right they are by comparison very simple."
Obviously there's clear and valued experience on here about the work in getting these carbs clean and running well. They do hold an advantage though in my view, in that they are more accurate especially at low speed range for metering fuel and probably outperform other fitment.
Specifically, their fuelling strategy results in less unburnt fuel to first contaminate the engine oil, and also the same for putting the byproduct of condensate into the exhausts. No small consideration when the pipes cost so much. The condensate is effectively laced with sulphuric acid from the sulphur in fuel and incomplete combustion, which is what makes it so aggressive to the exhaust pipe internal materials.
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