Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: daz on June 24, 2012, 03:24:49 PM
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Hi all, bike made a funny noise & broke down, had to be recovered home. Got to work on the engine today, found all the exhaust valves have hit the pistons & the static cam chain guide has broken in half.
Found the offer half wrapped around the crank between the cam chain sprocket & hivo sprocket.
Did manage to bash it off, also found 2 oil ways for the camshaft had bits of old o ring in, here are some pics, cheers Darren
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2 small pieces of what look like o ring stuck in the camshaft oil ways.
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Damn bad luck. Are the valves damaged?
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Sadly, bent valves are almost guaranteed :'(
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Bummer valves are bent, guides look ok, no cracks. :( :'( I do have 2 spare 500 four heads, can i take the exhaust valves from them? cheers Darren
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My bike is back on the road, at last, finished putting it back together last night & MOT done this morning, yes on a Sunday.
Went for a 80 mile ride to bed the new rings in, she runs well 8)
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Nice weather for it. 8)
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Those bits of O ring are far too big to have come upwards through the restrictors, only place i can think of is bits from the cam cover O ring joint
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just as an aside if that was mine i would be doing an oil change every 500 miles till 1500 then back to marmal Plus you can check oil flow in two ways:-
(1) remove the tappet caps and shine a torch in
(2) if you remove the end caps and loosen the bolt that holds down the steel bracket oil should pee out of there at quite a rate.
You repaired it quickly and well, Did you fit a new cam chain? and what state was the tensioner in, I will be honest and say I have seen a couple of badly worn front cushions but thats all---It was in the right way round wasn't it(inside the chain run) as if the chain is well mullered it can be fitted backwards and still get the chain on the sprocket
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Hi Byranj, not sure where the bits of o ring came from but both o rings where missing from the head gasket oil ways, the base gasket o rings where still there. Before i put the rocker on i made sure oil was pumping up to the cam shaft.
New cam chain (soft link), 4 x second hand exhaust valves vgc, new static cam chain guide, new tensioner blade, (tensioner undamaged) new rings, honed barrels, new gasket set, new oil & filter.
I used alloy wheel cleaner in the end on the head as it is so fiddly to clean.
Yes i agree i will change oil as you say, thanks for your advice, all the best Daz.
I found this chaps videos helpful
http://www.youtube.com/user/SocoMoto707
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Well It must be possible for those O rings to do that as it happened to you but I will say that that is an absolute first mate
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Still not sure myself that is what happened, just glad oil managed to get past the blockage as this is the 1st time since i owned it that the engine has been apart, 14 years & aprox 30,000 miles
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I've seen those o rings do that once- i think on my first 550. worse is when the tensioner lets go. I had one like the one in this thread. Bent valves. Alarmingly it did it again within months. I bought another where it had wrapped itself round the gear clusters destroying the whole gearbox effectively.