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Discussion Starter · #1 ·
I decided it was time to change the oil and clean the filters on my '75 CB360T.

Everything went fine -- oil drained, extraneous stuff removed:


Removing the crank case cover took a LOT of wiggling and some judicious application of a dead blow mallet, but finally it popped off. Naturally, the gasket tore into about 5 pieces.


Here's where things get weird. As I was taking the cover off, I heard something come loose from the inside of the engine and rattle around. When i pulled the cover all the way off, i found a small bit resting inside the cover. I think this piece mates the cover to the oil pump idle shaft, because its center hole has the same inner diameter as that shaft's outer diameter, and there's a resting place in the crank shaft cover that appears to be the right size and in the right location to hold it in place. However, I couldn't get the bit to go back into that hole. When i tried to put it in, it got stuck (bottom left-hand corner, the doughnut with the black center) :


while doing this, i noticed that the recess in which it is lodged has sharp edges -- could it have been rattling around and deforming the case? Maybe.. i found a sliver of aluminum that seems to match up nicely with the sharp edge resting on the inner surface of the crank case cover. It's not obvious from that picture, but the piece is not flush with the cover.

I had to improvise a tool to remove it, and it took some forcing. I winced the whole way through.





I'm not sure what to do next.

Is deburring the crank case recess a valid move?

What's the best way to remove baked-on gasket remnants from metal?

Most importantly, where DOES that stupid little piece go, anyway, and why did it fall out so easily but not want to go back in at all?
 

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Sensei
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I believe the bearing supports the pump drive gear shaft, and belongs in that hole....

Where's Leethal when we need him?....LOL....
 

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Discussion Starter · #3 ·
see, that's what i think too, and there's plenty of circumstantial evidence to suggest it. I can't seem to find that part named in the service manual -- but a similar looking part is present on the other side of the engine.

Also, it fell out as i removed the cover, and just refused to seat back in nicely. I can't see how it would've warped or lost its true during removal, either.

The aluminum shard suggests that it had enough play in that hole that it was chewing up the edges as the engine ran, too. Possibly too much play?

I'm pretty new at wrenching, so i don't have a lot of intuition for when something's clearly right or wrong yet.
 

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that's actually an oil seal, it doesn't have to seat perfectly flush with the hole, but it needs to have a good seal around the edge. I'm pretty sure that's a high pressure feed to the oil filter cylinder. I would reinstall it, it should be fine as long as it's not rattling around in it's housing. Also, now's a really good time to check your oil pump screen
 

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It is definately the BEARING for the oil pump idler gear shaft (according to the parts fische)... As to wether or not it is part of the pump to centrifugal filter plumbing, it does appear to be mounted across that passageway, but I have no direct knowledge of that... It does seem to be a sealed bearing, so it's possible.......D
 

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Sorry fellas, been slaving in a hot kitchen all day.....

That bushing does infact belong in that hole within the right case cover. It should sit flush with its housing and will mount against the oil pump gear shaft.
 

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Discussion Starter · #7 ·
leethal said:
Sorry fellas, been slaving in a hot kitchen all day.....

That bushing does infact belong in that hole within the right case cover. It should sit flush with its housing and will mount against the oil pump gear shaft.
OK, thanks.

how would you recommend i seat it and deburr the edges of the hole? Some people have suggested a hot-fit, in which the case is heated up a bit to widen the hole -- is this kosher? Is forcing it with a mallet and a dowel kosher?

There's a lip recessed in the hole that looks like it's the shelf the bushing sits on, and I'm concerned that just bashin' on it will deform that lip or make the bushing seat oddly.

Do you have any ideas about why it may have removed itself during crank case removal, but is now so difficult to reseat?
 

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I can't say why it would fall out, but not go back in at the same time unless you've got is slightly off square when you're trying to push it in.

It is definitely a bearing AND a high pressure seal for the oil pump output, which then travels through the filter and up through the case cover to the top end of the engine.

If you think the burr is keeping it from going in correctly then it wouldn't hurt to remove it, I'm pretty sure honda didn't leave any burrs in there on purpose. Just check and make sure the bearing still spins and as long as it fits snug in the cover (i.e. you have to drive it in) then you should be ok. Just remember to drive by the outer race, not the center.
 

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Sharkmonkey said:
It is definitely a bearing AND a high pressure seal for the oil pump output, which then travels through the filter and up through the case cover to the top end of the engine.
How can it be a bearing when it has no balls or needles, and why would it be 'high pressure' rated?
 

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"Bearing" simply expresses that it bears the weight and/or rotational stress loading of the (usually) shaft in the assembly.... Swingarm bushings are actually a form of bearing and have no balls or rollers...... Plain (flat curved metal) bearings are used on many crankshaft to connecting rod joints......
 

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Well, it doesn't spin as Sharkmonkey was stating.
 

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You may be right, but I recall an older post here on Hondatwins where Bill(?) stated that oil pressure was only about 1 or 2 psi.....it would certainly be something to explore. If I had a spare 360 I would do perform all kinds of "enhancement surgery" in the name of science :cool:

But I do know one thing, that seal/bearing/bushing does not spin. It is more or less identical to the rear shock bushings in your swingarm.
 

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leethal said:
You may be right, but I recall an older post here on Hondatwins where Bill(?) stated that oil pressure was only about 1 or 2 psi.....it would certainly be something to explore. If I had a spare 360 I would do perform all kinds of "enhancement surgery" in the name of science :cool:

But I do know one thing, that seal/bearing/bushing does not spin. It is more or less identical to the rear shock bushings in your swingarm.
I believe my comment was concerning 175/200/350/450, with the piston oil pump.
360 has the trochoidal pump, different setup, and I have no idea what the oil pressure might be............I have limited experience with 360's, that's why I never talk about them.

Now I know at least some of the SOHC Fours had an oil pump similar to the 360 type.
There has been some discussion of oil pressures for those bikes over at the SOHC Four forum.

Generally I think that if there were any real useful info to be had from a gauge, you'd see a lot more of them.
 

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You've probably fixed it by now but seals oil passage.
The idler shaft probably came out of housing in crankcase, it is pinned so cannot turn and pin probably wasn't in slot, which holds shaft about 3~4mm too far out.
With seal/bearing missing you have no oil pressure (which will be around 5~15psi)
I have done (and am still doing) lots of work and modifications to CB/CJ~250/360 motors (69~75mm bore, ported,etc)
 
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