Author Topic: Cb 750 owners how much oil do you add to the tank after an oil change?  (Read 8258 times)

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Offline lostmykeys

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 Trust me people need to know this.

Offline NewOldSchool

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This is what I do:

Fill it up with 3L of oil.

Kick it over several times or turn it over with the starter motor in short 5 second bursts with the ignition off to get some oil flowing.

Start it and wait for the oil light go out. (Should only be a couple seconds)

Let it run for a minute or two and look into the open oil reservoir , you should see small bubbles and oil flow as air is bled out of the system and to make sure its circulating.

Replace the cap and check the level

Fill the reservoir up until the full mark on the dip stick.

Go for a ride until the engine is fully warm.

Check level again after turning off the motor and letting it sit for a bit.

Fill as needed, otherwise you are good to go.
« Last Edit: May 30, 2012, 10:08:37 PM by NewOldSchool »
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Offline BobbyR

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That is about all there is to it.
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

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Offline Gordon

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Trust me people need to know this.

They really don't. 

I have been changing the oil in my own cars and motorcycles (and even other people's cars and motorcycles) for 22 years, and I've never once looked up or noted the exact amount of oil it took.  The dipstick gets the final word in all oil changes.  Even if you know beforehand exactly how much oil you need to add, you're still going to check the dipstick to make sure it's correct, right? 

When you're between oil changes and you check the dipstick one morning and notice you're a little low, do you drain all the oil, measure the volume, add however much is needed to bring it back to the full volume, and then pour all the oil back in, or do you just pour a little extra into the tank until the dipstick shows it's full?  It's no different when you're doing a full oil change.   

Offline lucky

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Starting a NEW thread on this???  >:(

THE OTHER WORN OUT OIL THREAD below:
http://forums.sohc4.net/index.php?topic=107690.0 :-\

OF course LOSTMYKEYS did discover the restrictor tubes in the fuel supply hoses on the 1977-78 CB750 carbs.

OK...What was the question?  ;D
« Last Edit: June 01, 2012, 12:48:46 PM by lucky »

Offline That 70s Bike

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...drain all the oil, measure the volume, add however much is needed to bring it back to the full volume, and then pour all the oil back in...
That IS, how he's doing it  ;D ;D ;D
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Offline lostmykeys

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 thanks Lucky,
 But Im sure this topic will come up again because the clymer manual gives two different amounts that are allmost a quart appart.

Offline MCRider

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thanks Lucky,
 But Im sure this topic will come up again because the clymer manual gives two different amounts that are allmost a quart appart.
I have a clymer's manual that says you have to remove the starter motor to take the head off. They are not the bible. You've received many responses here. The amount to use is the amount that gets a warm engine to read at the top of the hash marks. It is at least 3 quarts.

I say the difference the manual is quoting is the difference between draining the tank only or the tank, pan and filter, and probably the lines to, which no one does.

The question to ask is the reading done on the centerstand or on the floor. I say on the floor, or you'll overfill it.

Any amount that puts an inch or 2 in the tank of a warm engine is enough to run it. Then top it off to read on the dipstick properly and ride the thing.

PS: The post in your first thread from HondaMan should be your Bible, not a Clymer's.

There was a section in Zen and the Art of Motorcycle Maintenance where Pirsig talks about writing and editing technical manuals, as he did for a time. The writers/editors are seldom engineers and more seldom have any first hand knowledge of the product they are writing about. They are just compiling notes given to them from the engineering dept. who often take the attitude they have better things to do than give notes to the manual editor.
« Last Edit: June 02, 2012, 08:49:53 AM by MCRider »
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Offline jcarthel

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From totally empty to totally full, my 750 holds 3.5 quarts.  With oil and everything else, higher than a cat's back, a person just can't help noticing how much oil an engine takes when you change the oil.  I am a farmer, and my cat powered semi takes 15 gallons to bring the dipstick back to full, ouch that really hurts the wallet!  Gordon, I have been changing oil longer than you, so what gives, do you have a pump stuck in a 55 gallon barrel of oil for all your changes?  How can you not somewhere make a mental note of how much oil you are pouring in an engine, not for remembering, just an observation.  Oil changing is made easier by doing the same engine over and over.  An example is my wife's car, the manual calls for 3.6 quarts during a change, but it takes exactly 4 quarts to bring it back to full.  People do need to know oil level in a 750 for convenience sake.  Pour in the known amount, check the dipstick just to be assured, and your good to go.  Why make an oil change into something where every time it takes multiple attempts to fill the crankcase because you go by the seat of your pants? Refilling a crankcase doesn't have to be as time consuming as filling a graduated chemistry cylinder.  Sorry Gordon, but the man asked a fair question, why give a wisecrack answer?  If you can't help the man, don't answer his post.

Justin
« Last Edit: June 04, 2012, 12:22:22 AM by jcarthel »

bollingball

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jcarthel In Gordons defence ( not that he needs it from me) lostmybrain Whoops keys has ask this question over and over. Worried about that last 1/4 oz. If he is this OCD he will not get through a 3K tuneup before the end of riding season oh crap then the time will get him and he will have to start over. He may get on genesis world record for the longest time to figure out how much oil he needs. Then he will need to figure out what divice to use for measuring is that dry or liquid. Crap I hope he doesn't find out the imperial gallon. Then there is dipstick do you push it all the way down or just until it touches All this does not matter he will never get it started because he lost his keys  ::)
Ken

Offline lostmykeys

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 Bollingbag,
 The reason this thread has lasted so long is because nobody until,JCARTHEL gave a real answer to the question.
 The dipstick on my bike does not have a full or add mark on it,just hatch marks from the cap down to almost the end.
 The difference in 3.0 and 3.7  is over half a quart of oil so I dont know where you came up with a 1/4 once.
 When I change oil on anything I change the filter and drain the oil.Like JCARTHEL said its good to have a mental note on how much oil any machine takes.
 Look at these threads again and you will see that the question was never answered until JCARTHEL just common sense. I couldnt understand why no body knew how much oil they were putting in their bike.
 Ive been changing oil for 37 years and have never lost an engine.

Offline liPPy

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Bollingbag,
 The reason this thread has lasted so long is because nobody until,JCARTHEL gave a real answer to the question.
 The dipstick on my bike does not have a full or add mark on it,just hatch marks from the cap down to almost the end.
 The difference in 3.0 and 3.7  is over half a quart of oil so I dont know where you came up with a 1/4 once.
 When I change oil on anything I change the filter and drain the oil.Like JCARTHEL said its good to have a mental note on how much oil any machine takes.
 Look at these threads again and you will see that the question was never answered until JCARTHEL just common sense. I couldnt understand why no body knew how much oil they were putting in their bike.
 Ive been changing oil for 37 years and have never lost an engine.

I did look at this and the other thread you started on exactly the same topic and saw plenty of easy to apply, practical & sensible answers to your question from people with years of experience.

You chose to ignore them .

Offline lostmykeys

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Lippy
 I didnt ignore anyone as I read every response.
 But when you see  where some were getting .7 mixed up with .07 I could tell the original question was not understood.
 Just the other day I asked a question about setting the points plate and someone said to set the idle using the T mark instead of the correct way with the F mark.
 Anyway its time to move on.................next!

Offline Gordon

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From totally empty to totally full, my 750 holds 3.5 quarts.  With oil and everything else, higher than a cat's back, a person just can't help noticing how much oil an engine takes when you change the oil.  I am a farmer, and my cat powered semi takes 15 gallons to bring the dipstick back to full, ouch that really hurts the wallet!  Gordon, I have been changing oil longer than you, so what gives, do you have a pump stuck in a 55 gallon barrel of oil for all your changes?  How can you not somewhere make a mental note of how much oil you are pouring in an engine, not for remembering, just an observation.  Oil changing is made easier by doing the same engine over and over.  An example is my wife's car, the manual calls for 3.6 quarts during a change, but it takes exactly 4 quarts to bring it back to full.  People do need to know oil level in a 750 for convenience sake.  Pour in the known amount, check the dipstick just to be assured, and your good to go.  Why make an oil change into something where every time it takes multiple attempts to fill the crankcase because you go by the seat of your pants? Refilling a crankcase doesn't have to be as time consuming as filling a graduated chemistry cylinder.  Sorry Gordon, but the man asked a fair question, why give a wisecrack answer?  If you can't help the man, don't answer his post.

Justin

Justin,

I buy 4 quarts when I'm going to change the oil in my bikes.  I pour in three, run the engine long enough to circulate it, check the dipstick and pour in however much of the 4th quart that's needed to bring it to full.  I've never measured how much is left in that last quart. 

Just because an answer to a question isn't the one the asker was looking for doesn't mean it's incorrect or a "wisecrack".  I related real-life experience and gave an example to back up my statement.  I don't need you to tell me if my contribution to any particular topic is worthwhile or not.

Gordon 

bollingball

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Bollingbag,
 The reason this thread has lasted so long is because nobody until,JCARTHEL gave a real answer to the question.
 The dipstick on my bike does not have a full or add mark on it,just hatch marks from the cap down to almost the end.
 The difference in 3.0 and 3.7  is over half a quart of oil so I dont know where you came up with a 1/4 once.
 When I change oil on anything I change the filter and drain the oil.Like JCARTHEL said its good to have a mental note on how much oil any machine takes.
 Look at these threads again and you will see that the question was never answered until JCARTHEL just common sense. I couldnt understand why no body knew how much oil they were putting in their bike.
 Ive been changing oil for 37 years and have never lost an engine.

Good now you know how much oil you need.
That is all that matters
Ken

Offline BobbyR

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I think the responders with experience assumed that people knew that the hatch marks would tell you when the oil level was correct. It is in the shop manual which can be found in downloadable format on this site. It is vital to have one.
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline ekpent

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Nuthin' like a good old oil thread.no matter what form it takes  ::)  ::)

Offline BobbyR

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Nuthin' like a good old oil thread.no matter what form it takes  ::)  ::)
Nah, not yet. When the brand names and types come out you have a proper oil thread.  ;D ;D ;D ;D ;D ;D
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline NewOldSchool

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I'm sorry, I thought I couldn't have been more clear as the first answer to the original question.  ::)

If you have multiple hash marks on your dip stick then fill it up EXACTLY as the manual tells you to, wipe off the dip stick, check what mark the level is at, and remember.

Simple as that. If you can't remember then write a little note for yourself in the margin of the page in your manual that tells you how to change the oil.


Just to stir things up a bit.... I recommend Pro Honda GN4 in the 20W50 variety  ;D Comes in gallon jugs too  8)
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Offline lostmykeys

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 lets let the thread die down and just let it go away.
 I figured this out days ago.
 The clymer manual has two different amounts of oil in two different sections of the manual and the two amounts are almost 3/4 of a quart appart.An engine missing that much oil would cause loss of oil presure and possible overheating.
 I think my engine is running hot and that was the motovation for starting the two threads reguarding oil amounts in the first place as at that time I was only  running 3 quarts of oil in the bike after a full oil change.
 And when I change my oil on any bike I change it hot and remove all drain plugs and filter,tilt it both ways and use the kickstarter with ignition off to see if any more oil comes out.Then I let it sit over night and drip.
 The bike still seems to be running hot to me so I may have to check my timing advance again or check the oil pump screen to see if it's plugged.
 I just put clubman bars on the bike so that keeps me from riding too far from home in case the engine melts.
 I really think if any of you rode this bike you would say all is good and stop whining,
But its my bike and I'm hyper sensitive or "OCD "if you like to all it's functions and I need this thing to be as trouble free as the Z1 I sold for cash +two bikes in trade this f3 was one of the two.

Offline NewOldSchool

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Just for curiosity's sake to change things up... what makes you think your engine is running too hot? Its an air/oil cooled engine so if it seems to run hotter than a modern water cooled engine you are right.

Have you done anything to validate your worry it's running hot?

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Offline MCRider

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"An engine missing that much oil would cause loss of oil presure and possible overheating."

3/4 quart? On a CB750? I beg to differ. Beside understanding the design, I have this on personal experience as well. It won't lose pressure as long as there is enough oil in the tank to cover the lines. As to overheating it will heat a little bit more over a long period of time, maybe.

I said the bit about the level in the tank a least twice.  You just don't want to listen or think it through.   :(
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Offline lostmykeys

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 M.C, maybe your right and I'm not thinking it through I will entertain all variables.

Offline BobbyR

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+1 on air cooled engines. These motors do not mind running in hot weather, I have ridden mine at over 100F for hours. Having said that, they hate to idle for very long and will heat up very quickly. That is why you must use a good sized fan blowing directly on the front of the motor when working on it. I am talking 10 minutes or more in warm weather. You will have residual oil and chain oil start to smoke off the engine in 15 minutes.
The oil contributes a lot of cooling to the engine. 3.7 US Quarts is a lot of oil for such a small motor. You will notice the oil pan is fairly small and the bulk of the oil is in the oil tank. The early CBs had louvers in the side covers which may have been cosmetic and functional. A lot of air must get behind the covers since there are a lot of reports of covers blowing off. I suspect the tank contributes to oil cooling.

 
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline lostmykeys

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 Bobby R,
 I guess I shouldn't worry so much then.
 I thought that having a dry sump system would help with cooling but what concearns me is the fact that the cam covers get hot enough to make water or spit dance off them.
 But when you look up overheating on other sights everyone complains about the snaps and pops that happen while the bike is cooling down due to overheating.
 My bike does not do that so maybe its not overheating afterall, but I could fry an egg on the valve covers if I wanted to.