Topic: How much oil does a 750 really hold??

[Jim Shea]

Has anyone ever measured how much oil goes in to a 750? The book would suggest, 3.7 quarts, which I converted to 7.4 pints? but it depends on whether you use a US or UK pint as they are different? Would the manual have used US or UK measures?

When you look in to the oil resevoir, should oil be visible? I checked the dip stick which has a bottom and top line on it and the oil is registering over the top line! But, from the 5 litre can of oil I bought I reckon I used approx 3 litres when I changed the oil today??
Get your calculators out boys and girls.

[Jonesy]

According to my owner's manual, when you do an oil change it says to add 3 quarts to the tank after draining the tank, sump and filter housing. After you start it up, the oil level seems to settle down to the correct spot.

I think the 3.7 figure comes from starting with a completely dry engine- no oil in the galleries, none pooled up in the rocker box, etc. Again, this is just my theory...

I know Bob Wessner did a lot of research into this area... maybe he will post his findings! 

[Bob Wessner]

I've run into this myself. I followed the manual the first time and the end result was way overfull and had to remove some oil with a turkey baster (no longer used for turkey basting by the way  ). I had drained the tank, changed the filter, cranked the engine to remove any excess hidden anywhere, etc. I'm not certian how much it used in the end (will do so more accurately next change), but based on how much I removed, I suspect it is more like 3 U.S. qts to the top line of the dip stick, on the center stand, right after shutting down the engine. It's a K0 if that makes a diff., but I suspect it does not.

[Jim Shea]

Yes, I also followed the manual and this is my first ever oil change on the 750F. I think the crucial question is; should the oil be visible in the tank or not? I think that I could see the oil in the tank before I changed it?
Jim.

[Gordon]

I don't think it really matters if you can see the oil in the tank or not, as long as it's at the correct level according to the dipstick. 

[Jim Shea]

Assuming it is an original dip stick!! How does one tell? I expected to see a full and empty mark on it, btw, I have a 67 750F.
Also, if it were overfilled, where would it leak from?

[eldar]

This all depends on how well you drain the previous oil. The BOOK amount is 3.5 liters UK or 3.7 quarts US.
Now if you drain all locations, then you will probably add about 3. If you hit your kicker or the started a couple of times, more oil will come out as parts move and release the trapped oil, Then you will add about 3.2 or so quarts maybe a bit more.
The excess oil will come out of the hole for the filter bolt so leave that off while you do this.

[Jim Shea]

So if I got in about 3 litres, I shouldn't worry too much?
I still haven't had an answer from anyone about whether the oil should be visible in the resvoir? As I said, I am sure that the oil was visible previously, but I have just realised, this was probably when the engine was cold, so i will check it when the bike cools down.

[dusterdude]

jim,if i remember correctly,i filled mine up to the point i could see it in the tank.i think its about 2 inches or so below the cap opening.

[Jim Shea]

Thanks everyone.. I have just checked the tank with a cold engine and the oil is clearly visible, 1-2 inches from the top. I am glad I did not put anymore oil in when it was hot, or it would have overflowed. Then I would have had to use Eldar's turkey baster method!! 
As a new boy I can not tell you how chuffed I am that I managed to change the oil, oil filter and air filter and the bike still runs and does not pee oil everwhere; now if only I could get to plugs 2 & 3 the service would be complete! 

[mrblasty]

Here is a tip for getting to the 2-3 spark plugs.
attach a short extension to Your spark plug socket, slip it up through the frame extension up and then over the spark plug, it helps if the plug wire is out of the way and will need to snake around stuff to get it on.
When screwing the plug back in get yourself a 3'' piece of fuel line that will fit over the end of the spark plug 1/4'' I.D hose works great, make sure the piece of hose is straight otherwise it's a little bit tougher to thread the plug back in the hole and thread the plug to its seat then yank the hose off being careful when the hose breaks loose, You can whack the crap out of Your knuckles. The hose gives You something to grab in that tight area.
Running a '74 Dodge Charger with headers taught me that trick, I hated that car

[Jim Shea]

Blasty,
Sorry, I do not understand your solution? "attach an extension"?? what sort of extension?
Jim.

[Jonesy]

jim,if i remember correctly,i filled mine up to the point i could see it in the tank.i think its about 2 inches or so below the cap opening.

With it being a dry sump system, you NEED some oil in the tank. As one pump feeds the engine bearings, it draws oil out of the tank. True, you have a scavenge pump to replenish the tank, but it takes a few minutes for the scavenge pump to start moving an appreciable amount of oil. When my 750 ran low on oil (to where you could barely see anything in the tank), the oil light would flicker on and off, with my oil pressure gauge bouncing all over the place. Once the scavenge pump started moving the oil back to the tank, there was just enough to steadily feed the pressure pump and keep the bearings lubed.

How did I let my oil get so low, you ask? I had a phantom oil leak. It turned out my tach cable sheath broke and was spilling oil on the cylinder head, where it would drip onto the exhaust flanges and burn off. This happened over a one week period!

[Jim Shea]

Thanks guys. What I learned is to let the engine cool down and the tank will show oil in it, if you have put enough in? Sounds, simple but for any newbies, do not keep adding oil when the engine is hot or you will overfill it!

[Bob Wessner]

Jim,

Not sure that's right. The best time to check/add oil is right after the engine has been run (i.e., likely to be hot). The reason is there is a spring loaded valve sitting between the oil tank and the oil pump in the lower part of the engine. When the engine is running, pressure keeps this valve open allowing oil to flow between the tank and engine. When you shut off the engine, removing the pressure, a spring is supposed to close this valve and keep oil from draining from the tank to the engine, a condition often referred to as "wet sumping." Key phrase here is "supposed to close." It may not seal well and oil could slowly drain from the tank, mine does over a period of a week or so. Therefore, the best time to get an accurate reading on oil levels, or adding, etc.,  is right after shutting down the engine.

[jsaab2748]

jim
Bob's last post is correct. And maybe try checking the oil level with the dipstick just sitting in the fill hole, NOT screwed down. This last bit came from a Honda technician, so I always practice it. Haven't had any mishaps. I can see oil in mine.

[mick750F]

   This is from a '78 owners manual.

Engine Oil Level Check-

  Operate engine for approximately 10 minutes to stabilize level. Before the engine is warm, the level will appear too low.
   If the engine has been run at high RPMs, idle the engine at least 30 seconds before stopping the engine to prevent a low reading.

   Stop the engine, place the motorcycle on the centerstand, and check the level with the dipstick.
   Oil level must be maintained between the upper and lower oil level marks on the dipstick.

Filling Oil-

   Fill the oil tank with approximately 2.0l (2.1 U.S. quarts) of recommended grade oil. Start the engine and operate for a few minutes. Stop the engine, refill the oil tank with oil while checking the oil level with the filler cap dipstick.
   Run the engine for a few minutes, then stop the engine and check the oil level refer to engine oil level checking instructions.

   That's word for word...strange translation included.

Mike   

[Buffo]

I dumped about 3 3/4 quarts in to my 750K8 and had no trouble as of yet...I emptied the oil tank and drained the engine.

I had one bike that if you overfilled the oil it simply peed it out from a hose under the bike...i dont remember which bike it was...what will these do if overfilled?

Buffo The Magnificent

[Hop on a Honda]

What a subject to have a yak on. Oil levels is the key.
I managed to have a two hour blast up the Hunter valley today in 36degree C temp but when I returned to the Barn I managed to allow the beast to cool down for a minute or two.
Drove the beast into its normal position kicked the side stand into the prone side position and shut her down. Just as a mater of course I checked the oil level in the tank .It had grown by a good inch over the high tide mark.
Crazy Honda engine, but it's Ok the Japanese love a little more than normal but is it telling me that the Oil screen is playing up or clogged?
The Oil pressure light is OK.
PS I met a Honda retired designer many years ago in Australia who said that the oil tank filler cap and Dip Stick was designed to be read whilst on the side stand so as the stick its self was almost vertical.
Makes sense.
Dave Australia.

[Bob Wessner]

oil tank filler cap and Dip Stick was designed to be read whilst on the side stand

I agree. I seem to recall this was a subject of some discussion on the old board a while back, so I did a little experiment, checked the level with the bike vertical and on the side stand, the difference, if any was inconsequential.

[mick750F]

PS I met a Honda retired designer many years ago in Australia who said that the oil tank filler cap and Dip Stick was designed to be read whilst on the side stand so as the stick its self was almost vertical.
Makes sense.
Dave Australia.

   Yet the owner's manual instructs you to check the oil with the bike on the centerstand. 

[dusterdude]

inconsequential.look at bob throwing them big words around.keep it up bob and everyone here is going to think you are a k8 guy.

[Bob Wessner]

Yet the owner's manual instructs you to check the oil with the bike on the centerstand.

Well, I'd be curious to know the results if someone else tried it. Check it with the bike upright, wipe off the dip stick then check the level on the side stand. On my K0 the diff. was less than an 1/8th inch and I think my side stand has a slight bow it in that would cause the bike to lean a tad more. If anyone else tries, post your findings.

[ofreen]

When I change the oil and filter on my '75 750, three quarts brings the level in the tank to the top mark of the dipstick.  It doesn't seem to matter if the engine is hot or cold - there is not much variation.

However, there is one thing the owner's manual tells you to do that I never do anymore because I don't think it is a good idea.  The owner's manual instructs you to operate the kickstarter several times to purge residual oil from the engine after draining the tank and crankcase.  I did this years ago when I first got the bike because it seemed like a good idea to follow instructions to get as much of the "dirty" oil out as possible.  One time though, I neglected to do the purging routine and I noticed something interesting.  When I would purge the engine using the owner's manual procedure it took a few seconds for the oil pressure light to go off on the first start-up.  When I forgot to do the purging, the oil light went off immediately like during any other start-up. 

It seems to me that the little bit of old oil left in the engine is inconsequential, but several seconds of low oil pressure is not. 

Or maybe it makes no difference, I don't know.  I do know I hate to see that oil pressure light on for any length of time.

Greg
'75 CB750F

[dusterdude]

greg,if you kick to purge.then kick to put oil back in the sump.