Author Topic: Here it is...the clogged oil pump screen (pic)  (Read 19364 times)

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Offline Industrial Cafe

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #50 on: July 14, 2009, 07:02:16 PM »
*sigh*
    Now I'm gonna pull my pan on the next oil change
I put a "new" motor in without doing it.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

Offline TheHun

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #51 on: July 15, 2009, 06:32:00 AM »
at least we know the honda made piece did its job...unlike other manufactureres :)
1978 Honda CB750-K

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Offline Bob Wessner

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #52 on: July 15, 2009, 11:57:23 AM »
Blackmax,

Would you mind if I moved a copy of the photo to the Damage album in the Gallery? It's pretty impressive.

Pic has been saved for all eternity  ;) in the Damage Album of the Gallery.
We'll all be someone else's PO some day.

Offline HondaMan

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #53 on: July 31, 2009, 01:08:44 PM »
HM: Is Threebond, like 1194 for instance, latex-based?

Yes, I believe it is (sorry for the long delay). Threebond and FelcoBond used to be the only products around in the "old days", but in 1972 or so Yamaha brought their YamaBond here, and we used it on every gasket that needed sealing. In the 1990s Honda brought their HondaBond, which seems to be the same 'stuff'.

In the last few years, it has all proliferated into several "versions" that I don't understand, like #1, #2, #3 and #4. The gray #4 stuff, with consistency like mayonnaise, is perfect for the engine cases AND all the gaskets, and is surprisingly easy to remove during a later teardown.

I also happily, recently, discovered that it will hold pure synthetic oil inside the cam cover on my 750!  :D :D
« Last Edit: September 26, 2009, 06:38:20 AM by HondaMan »
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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Offline cookindaddy

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #54 on: September 25, 2009, 11:28:36 AM »
I noticed this thread before and I am now looking at my oil screen and it looks pretty good. I cleaned out the little bit of grunge that was caught in it and now I see bright shiny screen.

Is it necessary or desirable to remove the oil pump screen from the housing? If you wanted to, how do you get it out? I want to pry the rubber ring away from the oil pump housing with a small screwdriver, but I don't want to damage anything.

I'm looking at the Honda shop manual for the 1978 CB750K and they say only "remove the oil screen from the oil pump base. Clean the oil screen in clean solvent". No clues there on how to actually remove the screen.
George with a black 78 CB750K (in Lion's Head, Ontario, Canada)

Offline BVCB650

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #55 on: September 25, 2009, 11:45:36 AM »
I once ran a bike through a creek, and hit a deep hole where a bunch of water got sucked in and sort of steam cleaned the combustion chamber. Pulled the pan off to look things over, and it looked like a bunch of nuked slugs on the screen, but your wins top prize.
1979 CB650, 25K miles, recently refurbished

Offline MCRider

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #56 on: September 25, 2009, 11:51:55 AM »
I noticed this thread before and I am now looking at my oil screen and it looks pretty good. I cleaned out the little bit of grunge that was caught in it and now I see bright shiny screen.

Is it necessary or desirable to remove the oil pump screen from the housing? If you wanted to, how do you get it out? I want to pry the rubber ring away from the oil pump housing with a small screwdriver, but I don't want to damage anything.

I'm looking at the Honda shop manual for the 1978 CB750K and they say only "remove the oil screen from the oil pump base. Clean the oil screen in clean solvent". No clues there on how to actually remove the screen.


It is VERY difficult to remove a screen especially without messing it up and they are not available separately.

I heated mine with a hairdryer and worked it out with jewelers screwdrivers. There is a steel ring covered by the black rubber ORing that you see, all one part. The rubber ORing is notched into the pump body.

So you pry it away, and up about like removing a tire. But you must go very slow and gently to avoid putting any more of a dent into the ring than you will. Once I had it out i was able to pretty much restore the small dent and the whole thing looks circular again. I haven't tried to get it back in yet.

If you don't have to, don't do it. Use a fine brush and a vacuum cleaner to clean the screen and leave it be. IMO
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline cookindaddy

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #57 on: September 25, 2009, 12:02:31 PM »
Thank you MCRIDER. All your advice was accurate. By the time I read it however, I had already gone ahead and pried it out with a dull small screwdriver, dinting the edge just like you said, reformed the edge carefully, cleaned it in solvent and gently pressed it back into place. Some gentle pressure is required to put it back, but now that it is in there, I don't think it is going to come out by itself.
George with a black 78 CB750K (in Lion's Head, Ontario, Canada)

Offline MCRider

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #58 on: September 25, 2009, 12:20:22 PM »
Thank you MCRIDER. All your advice was accurate. By the time I read it however, I had already gone ahead and pried it out with a dull small screwdriver, dinting the edge just like you said, reformed the edge carefully, cleaned it in solvent and gently pressed it back into place. Some gentle pressure is required to put it back, but now that it is in there, I don't think it is going to come out by itself.

Ta Da!  There you go, you've done something that many others have never attempted. Glad to know it popped back in OK. I thought it should.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline HondaMan

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #59 on: September 26, 2009, 06:54:31 AM »
Thank you MCRIDER. All your advice was accurate. By the time I read it however, I had already gone ahead and pried it out with a dull small screwdriver, dinting the edge just like you said, reformed the edge carefully, cleaned it in solvent and gently pressed it back into place. Some gentle pressure is required to put it back, but now that it is in there, I don't think it is going to come out by itself.

Ta Da!  There you go, you've done something that many others have never attempted. Glad to know it popped back in OK. I thought it should.

MC:
Would you estimate that the O-ring might be something that we could replace with a new one? Just curious...I've been spending a lot of time with the local seal house, finding common O-rings that cost half as much as Honda's for these engines. (I'm working on 6 engines, O-rings are getting expensive!)

I have now a whole BAG of the O-rings for the little valve caps. I use them on bikes that come by for a tuneup and have hard, leaky ones. Honda's peculiar size callout seems to be for O-rings that were custom-made to reduce the amount of material (and thus their costs on thousands of bikes) to a minimum level: I have found superior tranny performance, for example, by using an O-ring of .1mm extra thickness on the countershaft bearing holder where it feeds the oil to the mainshaft gears. The one that came in the Vesrah kit was the same as Honda's (a 2.4mm cross-section) here, and after 20k miles it was shrunk enough to leak a little again: as soon as I installed this new one and rode about 50 miles, the difference was apparent.

This same scenario applies to the ones on the 550 oil pumps and 750 oil pumps and hoses: those have a callout of 2.4mm cross section, and the 2.5mm ones increae sealing face size by 2.5% and pressure by almost 5%, still well within the squish callouts recommended by the O-ring manufacturers (18-23% squish for seals).

My goal, here, is to provide superior sealing for use with synthetic oils. I have found several weak sealing spots on my K2 with the Mobil 1, but like the performance so much that I want to stay with it: so I'm improving the seals everywhere (just so I can go back and add it to my book, now that the section was already finished...  :-\ ). The cam cover, after about 5k miles and a new (almost new) oil pump, started leaking (it has the Yamabond), so I'm going to attempt the Aviation Permatex paint-on up there this next time. You have to apply it 4 times: once to the gasket and cam cover, dry a little, stick together, repeat with the other side. (No wonder airplanes cost so much!)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline MCRider

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Re: Here it is...the clogged oil pump screen (pic)
« Reply #60 on: September 26, 2009, 07:58:14 AM »
The "ORing" that surrounds the screen is an integral part of the screen. Bonded on I think. Can't imagine any way it sould be replaced. Seems to me its purpose is not to seal anything, after all the screen is there, but the lip on it fits into the body and holds it there.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."