CA95 & the gravity defying Oil!

[rachelaustin]

So in the nook in the top center of the case, right near the cam adjuster, I kept seeing oil build up in it. We looked and looked to see where it was dripping from and couldn't find anything. It was always completely dry. Then I was letting it idle and we were looking at it and saw little air bubbles in that nook of oil. Turns out the oil is coming up out of the case.

This would seem like some sort of breather is clogged? I'm not sure at all.....

I rode to work this morning and everything was fine, pulled up and parked on the sidewalk in front of work as per usual, shut it off, went in..... then I went out to look at .... well both my bikes today, as my father rode my Yamaha in today.... and saw a big oil pool UNDER the bike. This time the nook on the top of the case looks as though everything in there drained out the bottom of the bike as it was completley clean.

How/What could this be? And are there any random parts I should have on hand before tearing it down?

Thanks!

[Smithers]

Morning,

Post up a picture!

The breather for the whole engine is the plate that is bolted to the top of the cylinder head. There is a thick gasket under it so if you remove it be VERY careful if you want to re-use it. It might be damaged from deteriorating. I doubt it though. There is a hose that attaches to it so you might want to check that out.

I'm curious as to the area at which the oil is coming out of. That's not a good thing. Check the breather of course. I would expect the oil to come out of one of the seals before a gasket area. I hope there isn't a crack somewhere! If the breather isn't malfunctioning then it sounds like a bigger problem. : /

[rachelaustin]

http://img.photobucket.com/albums/v19/shesbeenshot/thereoilred.jpg

http://img.photobucket.com/albums/v19/shesbeenshot/thereoil2redgreen.jpg

Like I said... It would pool up in that nook, then today it just decided to drian. I'm amazed that the oil level is still perfect.... is it possible that the oil was overfilled? Nah, that'd be too easy.... ha

[Smithers]

Hey glad to see some pictures! I kinda had a good idea of what you were saying but it's hard to imagine the oil pooling up in that area... because where it's pooling up: that gap should be clear! It should be able to go all the way through the bottom of that recessed area and drop on the ground. I'm thinking you overfilled it. The oil breather is right on top of the cylinder head as I mentioned before. Well check where the hose goes from that breather. It might be dripping the oil right down on the top of the engine where you are seeing it.

So make sure and get some tools to run down in that area where the oil is pooling up. There is something letting the oil drip onto the top of the crankcase right there. It can't be broken right in that area or coming up from inside there but it should be nice and clean/clear there so the oil goes right through.

Lemme know what you find.

[Smithers]

ALso the covers that are right behind the carburetor - Take those off and look in there. The breather hose should go over the engine and back around down through there. It could be drooling out from the cover and going forward into that area where you are seeing it come out.

[juicemavin]

Sorry to jump in so late... just found this site today. This is great.

I'm wondering if it's not from the breather on the back side of the cases on a later model CA. I just finished restoring my motor and notice just from kicking it over by hand that there seems to be an excessive amount of air or something blowing out that breather.

Assuming I did this right I tried to attach a photo... it is the cylinder shape thingy coming up out of the back of the case.

If that's not what causing your problem... I'm wondering if it's normal to have a any amount of air coming out of it. The service manual refers to it as a breather but it seems odd that it's a noticeable amount of air coming out

[Sam Green]

Are you sure it is oil that is pooling in the recess on top of the crank case.
At times, the recess gets dirty and blocks the drain hole in the bottom of the recess.
I have known this to happen and the recess can fill up with gas (petrol) if the carb overflows.
The gas then loosens the muck blocking the hole and the gas then drains through under the motor.

Juicemavin, It would seem that you have a mixed up motor.
From the picture you have crankcases from an early model with the breather on the crankcase above the gearbox and the top engine mount with the breather on it from the later model. It's not a problem, just letting you know.

Sam.;)

[Spokes]

Yep. Sam beat me to the punch. There was a change in engine design in 1964. Pre 64 you had a breather (like yours) on the top back of the engine case, and a solid cylinder head cover. After 64 the top case did not have a breather. Honda re engineered the breather into the cylinder head cover and ran a tube into the manifold insulator, which diverted the pressure into the intake manifold for reburn. It was the early stages of reducing emissions.

You will get lots of air from the cylinder head cover tube. It comes from the downward motions of the pistons.

So, depending if you have a 64 and after cylinder head assembly, you can attach a carb insulator from a post 64 engine and run a tube from the breather to the insulator. Or if it is a pre 64 engine plug the hole and let the engine breath as designed- or- if you want to be really wild, connect the smallest breather check valve from an old 283 chevy engine and divert the end of the tube into the air filter.

[juicemavin]

You guys are good... Thanks for the info. I actually have 2 motors that I have been piecing together. The original head that was on this one was all bent up with a bunch of the cooling fins busted off.

I've tried to figure out what year I have but have not been able to find anything. Most sites only show a series of numbers after the CA95. This one has CA95 - A#####.

Thanks Guys for all the helpful info. I'm absolutely loving working on this bike. I'm off for the next two days and told my wife I'm locking myself in the shop as it is assembly time. Motor is back together (thanks to the help of this forum) Frame is back from the paint shop. Now it's time to see if I can remember how I took it apart.

Thanks again. I really appreciate the help.

[Sam Green]

I doubt that anyone on here has had one of these bikes from new.
When you buy one, there's no saying what the previous owner has got mixed up when he decides he could do it himself cheaper than a trained Honda tech.

Spokes may have aquired his bike with the top end breather attached to the carb insulator but this is incorrect.
The rotory funnel breather on the old motor bleeds to atmosphere but the top engine breather should bleed into the air fillter housing.
The breather from the carb insulator is somewhat of a mystery :confused:.
I have never asked what it is for but it goes through the head from both sides of the insulator, through the valve guides and to the inlet valve stems.
Due to the fact that the valve stems do not need to breath, I can only conclude that it is to aid cooling.
Having said that, why do the inlet valves need to be cooled when the exhaust valves must reach much higher temps.:confused:

Sam.;)

[Spokes]

Quote from the service manual

The breather design change is applied to each model starting from engine numbers:
C92E-1193875
CS92E-2700001
C95E-2100001
CB92E-2100001
Description of Change
The crankshaft is reinforced by using larger bearings and the housings for the bearing of the upper and lower crankcases are also given additional strength.

For this purpose the "funnel type" breather pipe secured to the upper crankcase has been done away with in order that the negitive pressure accumulated within the case is discharged through the head cover.

Drawing E-1 Cylinder . Cylinder Head drawing shows the breather tube directed toward the insulator on the carb, the insulator showing the port where the tube attaches.

Today, seeing Sams advice, I happen to have a completely disassembled cylinder head for a 65 Honda CA95 engine. Using compressed air and directing the air into the small holes of both sides of the intake bore resulted in the air exiting through the intake valve guides. Thus the head pressure directed into the carb insulator forces the crankcase gases into the intake port of each intake valve. This in turn draws in the crankcase gases and burns them with the fuel.

That's my take on the issue. The mystery of the carb heat insulator port solved. No you don't have to connect the breather tube, but you engine will breath in air with the insulator tube being left open and if you run the cylinder head breather tube back to the air filter, that will do the same thing.

Having stated my case, if you have sloppy rings you could build too much pressure for the insulator port to handle, thus blowing off the tube, then you run it back to the filter.

[Sam Green]

OK guys, It's official, I'm a fool.:o:o:o I've just been into a room at work that is used for training purposes. On the wall was a sign saying, If you ask, you're a fool for five minutes, If you never ask, you're a fool for life.:D:D:D
I did say that the breather from the insulator was a mystery to me and that I had never asked what it was for...that it would seem makes me a fool.:o
What I didn't say was that I knew what Hondas take on the subject was.
The translation from Japanese to English in the early days was a little to be desired and was (and I did say was) about as clear as mud.
This is a quote from their workshop manual dated June 30th 1960.
One thing that is clear is the mention of this carb insulator breather going to atmosphere. Here is the quote.

[On the middle of the inlet valve guide, a slit is cut around which is lead to atmosphere through a drilled hole in the head. Therefore, care is necessary that the holes coincide with each other in case of replacement.
This device is provided to prevent oil invading through the guide and valve stem clearance.]

Allthough it is understandable what Mr Honda is saying, I can't for the life of me figure how a hole half way down the guide will stop oil seepage once wear sets in.:confused:

Going back to where the two breathers go, If you look at the stubs where the two breather pipes take off from, you'll notice that they are different sizes. The top one from the head cover has a black rubber pipe with a much larger diameter than the one from the carb insulator which is clear plastic.

Here's another reason why you might not want to feed the top breather to your valves.
Over the last 30 years, the rules for racing motorcycles insist that all machines have their main engine breather terminating into a catch can.
This is to catch any oil spillage in the event of piston failiure.
It is wise to check the contents of the catch can from time to time and the only thing I have ever witnessed in a catch tank is water.
Spokes was correct when he mentioned the pumping action of the pistons.
Not only dose it pump air out, the negative wave sucks air in as well but you can't feel it.
The heat in the motor turns the moisture in the air to steam and on a cold day you can see it exiting your breather just the same as you will see steam coming out of your exhaust. If you want to pump water into your valve guides, be my guest, remember, I'm just a fool:p an old fool with 45 years experience racing and road miles with these motors.:D:D:D

Sam.;)

[Spokes]

Mr Sam
If your a fool, than I am a fool. We are both old fools. This is not an argument or a point counter point. I too share racing experience, but with alcohol fueled dragsters. The info on old Honda's is hard to decifer. The whole thing about where the breather goes can be discussed forever.

It's just a hobby, vent the motor, circulate the gases matters not. Anyway, some engineer may of thought of this breather idea, put it in place, did not work worth a damn and changed the design. Case in point, I have been on the inside of Ford corporate and I can't begin to tell you how many ideas get tried, run and changed on the fly with failures buried to the point that no one on outside will ever figure it out. In 1988 Ford repainted over 1 million F150's because some plant engineer made a process change at a stamping plant that affected paint adhesion.

A supplier took the hit. The engineer worked another 10 years and retired well to do.


When I answer questions, it's to the best of my knowledge, and as you, 4 decades (sounds better than 40 years) of experience in many phases of life, one can answer like a lawyer defending a case. But we may be trying to figure out why someone in 1964 made a decision about a design change on a small low horsepower engine in Japan.

The racing and high rev's, moisture and combustion, engine breathing is just a cool subject and when comparing old and new technology, it can be a life long discussion.

But really, the old Honda with about 16 hp with a single carb is just a hobby.

My apologies go out. This forum is nice. No fools here in my opinion.

[Sam Green]

Hey old fool, :D seems like we have more than just Benlys in common, I to at 64 am still drag racing. :eek: I race a Honda CB750 automatic in the AMA drag bike series. The bike is under going a serious make over at the moment in Boston and won't be ready untill the end of the year, I hope to make the finals though at Valdosta in November.
Talk about alcohol fueled dragsters, the last time I ran the Benly in real anger was back in 71, it was fuel injected on 100% nitro, I won't tell you what the results were though.:(:(:(:D:D:D:D If I knew then what I know now, I'm sure the little bike would top over 100mph on just alcohol, maybe another day soon.;)

Sam.;)

[Smithers]

100 on a Benly? You guys are fools. :D I thought going for 100 on my CB72 would be somewhat brave but now it's just child's play to me. :)

[Sam Green]

Hey Ryan, did you see my Benly, about quarter the way down this page.

http://forums.sohc4.net/index.php?topic=46104.125#lastPost

Sam.;)

[Smithers]

The black 175 one?

[Sam Green]

The black 175 one?

A lot lighter, lower and faster Ryan.:D:D:D:D It's cost me a fortune over the years.:mad:

Sam.;)

[Smithers]

Wow. I want some details on it. Yeah I've seen some blurry pictures and heard some wild tales about the fast ones like that. :) We won't talk about how much money goes into those tho.

[Sam Green]

Wow. I want some details on it. Yeah I've seen some blurry pictures and heard some wild tales about the fast ones like that. :) We won't talk about how much money goes into those tho.

I'll start a racing Benly thread when I have time Ryan, I'll also have to get my junior team member on board to post pictures. Apart from not knowing how, useing the company computer prohibits me from posting lots of things.:mad:

Sam.;)