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Author Topic: Oil to the head.....  (Read 1440 times)

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Offline Mossy21

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Oil to the head.....
« on: January 25, 2007, 04:52:26 PM »
I'm on my second '78 CB750k restoration and both bikes had engine trouble when I bought them.  The camshaft seized on one side due to the oil jet getting plugged.   I know the two jets are there to increase oil pressure to the valve gear, but is there a fix for this or do I just keep changing oil and filters like crazy and hope for the best ?   Thanks in advance... :)
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Offline mrbreeze

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Re: Oil to the head.....
« Reply #1 on: January 25, 2007, 05:43:35 PM »
Hey Mossy,I'm not familiar with these jets you speak of because I haven't been into these motors yet. What plugged it up? Crusty oil? Metal  fragments? I would say running the engine with dirty oil,lack of oil,broken internal parts could cause that kind of damage.
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Offline Jonesy

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Re: Oil to the head.....
« Reply #2 on: January 25, 2007, 05:51:10 PM »
Did anyone have the heads off before you got them? Usually this seems to happen when gasket sealer is liberally applied to the gasket area around the oil feed O-rings and oozes into the oil gallery on reassembly. Then, it works loose and clogs the oil jet, cooking the valvetrain.

The jets are actually to act as a calibrated restriction in the oil feeds, ensuring that the main crankshaft bearings (under higher loads) get the lion's share of the oil pressure.
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Offline mrbreeze

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Re: Oil to the head.....
« Reply #3 on: January 25, 2007, 06:29:38 PM »
Quote from: Jonesy on January 25, 2007, 05:51:10 PM
Did anyone have the heads off before you got them? Usually this seems to happen when gasket sealer is liberally applied to the gasket area around the oil feed O-rings and oozes into the oil gallery on reassembly. Then, it works loose and clogs the oil jet, cooking the valvetrain.

The jets are actually to act as a calibrated restriction in the oil feeds, ensuring that the main crankshaft bearings (under higher loads) get the lion's share of the oil pressure.
That sounds like a reasonable scenario. If you are a mechanic.....you are a detective.What clogged those jets to starve the cam bearings????
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Offline eurban

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Re: Oil to the head.....
« Reply #4 on: January 25, 2007, 06:51:21 PM »
As mentioned it is usually a problem caused by too much sealer or from very negligent maintenance.  There is not an inherent time bomb waiting explode with these motors so just maintain it properly and enjoy. 
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Offline mrbreeze

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Re: Oil to the head.....
« Reply #5 on: January 25, 2007, 06:56:34 PM »
Quote from: eurban on January 25, 2007, 06:51:21 PM
As mentioned it is usually a problem caused by too much sealer or from very negligent maintenance.  There is not an inherent time bomb waiting explode with these motors so just maintain it properly and enjoy. 
And so it is noted........GOSPEL BABY!!!!!!!!!!! ;) ;) ;)
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Offline Mossy21

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Re: Oil to the head.....
« Reply #6 on: January 25, 2007, 07:07:15 PM »
It just seemed strange for both bikes to have the same problem.   Now that I'm the owner, I'll keep maintenance up for sure.  As for what I found in the clogged jet.....  It looks like oil filter material.  Cheap filters I figure.
PS  Thanks guys for all the info.  ;D
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