Topic: Question for Hondaman re: Oil Capacity

[firecracker]

Here's some (mildly confusing) info about dry and wet measures:

http://en.wikipedia.org/wiki/U.S._customary_units

Ever notice that wikipedia knows everything?!?

Maybe we should look up cb750 oil capacity there...

Kyle   

[cbjunkie]

http://en.wikipedia.org/wiki/Special:Search?search=HONDA+750+OIL+CAPACITY&go=Go

you're up, bob... 

[Bob Wessner]

http://en.wikipedia.org/wiki/Special:Search?search=HONDA+750+OIL+CAPACITY&go=Go

you're up, bob... 

Yeah, I'd write it up as 3 qts on a change and 90% of the owners would give me you know what about it. 

[cbjunkie]

it would probably end up being the longest wikipedia topic ever know to mankind...or at least the most often "corrected"...but, hey, glenn might appreciate it if we use up their bandwidth instead of his. 

[Hop on a Honda]

Interresting I managed to get all oil from the engine by simply getting a 1" board under the footprint of the  Rear tire to give the CB 750 a bigger list to Port (Left for the unwashed) on the side stand.
Seems to work for me as well as running the engine over a few times  in the Kill position.
The Alternator casing can have some hung up too.All adds up.
Use PENRITE OIL HPR 30.
 Much better.
!!
Dave
PS let god sort it out!!

[techy5025]

Bob,

Does the K0 have a cylinder that extends into the oil tank?  I seem to remember
that there was one that may have gone away in later years. Maybe part of the
breather hose assembly that attaches to the back.

I have never measured the oil capacity of the two bikes.  The diecast is due for one...I
will measure and report back.  I should have measured with the sandcast because it had
zero oil in it when I filled it.

Maybe you are filliing the alternator up with oil. 

Jim

[Bob Wessner]

Jim,

See pic, is this what you are referring to?

I'm not losing sleep over this, since it has always been this way on my bike, but at the very least it is curious if it is supposed to take close to 4 qts on a change. On the other hand, assuming this is correct either I have the better part of a qt I never get out and the oil is never really clean, or I'm shy nearly a qt and the cooling capacity, at least for that which is attributable to the oil, is reduced by nearly 25%.

[HondaMan]

I found it, Bob!

I looked at my oil tank "intrusion" today, like yours, and it is only 1cm (about 3/8") from the back-of-tank to the battery box (tool tray removed to view). where your picture shows a lot more distance. I'll try to post a picture of mine here shortly.

For whatever reason, your tank is not as "thick" as the others. 

[Bob Wessner]

I think you made my day, but not sure I follow, look forward to the picture. Why would they have different dimension tanks? Is mine not what is supposed to be on my bike? 

[HondaMan]

You got me there: I have no idea why there might be 2 different K0 tanks.  ?

Here's the K2 pix.

[Bob Wessner]

Mark,

Wow! They sure are different. Hmm, wonder why? At least I have an explanation. Do you think the difference is sufficient to cover the capacity difference we have been talking about?

[HondaMan]

Almost exactly. I measured the "back side" of the K4 tank I have on my garage floor, and it comes in a little over 26 ounces of volume, when converted from cubic inches to cubic ounces. Since it doesn't get filled all the way up, this makes perfect sense.
The only part that DOESN'T make sense is: how did you get that tank? There's no other U.S. Honda model that uses this tank that I've ever seen. The Yoshimura tanks for the CB750R "kits" were either the same size or an extra .7 qts bigger, at 4.2 quarts.

However, in Japan there was a 700cc version of this bike, so I've been told by some Viet Nam vets I know who spent quite some time there. I've often wondered if this is the legendary model of the 2 that I saw in the Chicago area around 1970. These were the ones with no "736cc" marks on the cylinders: I also wonder if they were 3 quart oil tanks.      

And, if your cases were replaced, I wonder about the other things? The odd ones I refer to had longer stroke (I think it was 64mm+, don't have my notes at the moment), and noticeably smaller bore than the standard 750. Do you know a lot of the bike's history?

Either way, changing the oil on schedule should prevent any issues. The "schedule" for K0 was 1000 miles. By the late K3, Honda had changed the manuals to read 1500 miles, and by the K4 engine enough changes had been introduced to make 1500 miles not a problem.

[Bob Wessner]

Do you know a lot of the bike's history?

Actually, no, I know very little. I'm the second owner. Bought it in '74 or '75 as my second bike and have the orig. title document. It was first titled in '70, which makes sense based on the VIN date of 12/69. My first, a CB350 twin was a bit under-sized for me, but good one to learn on and I was just looking for something physically larger. I tend toward over maint. anyway, so the oil has always been changed at around 1,000, with the possible exception of a long trip years ago from Mich to the east coast and back.

I can see where increasing the oil capacity might help cooling issues a bit and increase engine longevity. Do you think it would be worthwhile to try and find one of the larger capacity tanks? Since the increase it toward the rear of the tank, it wouldn't affect the side-cover clearance.

[HondaMan]

I have that extra K4 tank, if you want it. I don't need it anymore. You may have to do some serious cleaning/boiling or whatever, as it sat in a boneyard for 8 years before I inherited it. I can't imagine why it wouldn't fit, since the ancillary parts never changed. I think it even has the dipstick and breather tubes still on it, but not the oil hoses.

If you want it, PayPal me about $10 and I'll take it to UPS (or the Post Office or something cheap to ship). Send your address, too. My PayPal is:  mgparis@concentric.net  .

[Bob Wessner]

Thanks Mark, I think I will give it a try. I sent you an eMail.