4.1 qts vs 5.8 qts ?

[Mike Cecchini]

Came across something I'd never really thought about much over the past 10 yrs of X ownership and oil changes. Most times I simply use the dip stick as a filling guide because I've run into so many handbook misprints over the years. But last week I pulled out the original owners handbook on my 80 to see how many qts of oil to get out of the shed to change the oil on my newly re-assembled 80 top end work done this winter.

The handbook clearly said 4.1 qts for fill-up with oil filter change-out .....so I dumped 4 qts into the fill hole and it clearly wasn't enough visually (just below the fill hole threads and the original dipstick showed this. I even went to my other 80X and got it's dipstick to make sure the one I was using was the right length....both the same.

I got out the factory service manual and lo and behold..... "5.5 liters" (5.8 US qts) was listed. Then, just for grins I went on-line and found a Cycle World article on the 80X http://www.cbxclub.com/davespage/cbx80-4.html , http://www.cbxclub.com/davespage/cbx80-6.html ....with it's comments about the 20% increase in oil for the 80 vs 79..... clearly implying that Honda saw a need to increase the oil capacity for some reason.

1. Any thoughts on why the 79 4.1 qts might not be adequate ?

2. Did the increase 5.8 U.S. qts follow on to the 81 & 82 X's ?

Thanks.

[spencer]

I think the 4.1 quarts is all that will drain out through the drain plug and filter change. The rest of the oil remains in the engine unless you dismantle it and really remove all of it.

[Mike Cecchini]

I hear you Spence......but all I did was drop the drain plug and take off the filter housing.......and it took 5.5 quarts to bring the oil level just below the oil filler threads.

Frankly, I couldn't believe my eyes......but dem's the facts.

[Larry Zimmer]

While I haven't compared the sump size between the two, I'd suspect/guess that there is enough difference to take the extra quart. And, mostly likely, someone at Honda saw a need for additional heat capacity. Nothing like some extra oil in an airhead.

[Mike Cecchini]

Totally agree Larry...... never too much oil..... as long as the engine has the capability of getting all of it up to proper temperature. Just one of the reasons why so many race machines have dry sump engines and HUGE remote oil tanks.

Bottom line..... Honda saw fit to increase the 79X 4.1 qts oil capactiy to 5.8 qts capacity on the 80X.......but I'd like to know exactly why they did this........and if the 5.8 qt capacity was kept for the late model engines also.

Thanks

[Larry Zimmer]

Yes, Mike. The 81/82 Manual shows 5.8 qts. Gotta be for heat/cooling. A question(s) I don't know the answer: is the cooler larger on the later bikes? How about oil pump size? Any different displacement for the pump? Or drive speed?

[Don]

It takes lots more than 4 quarts to fill my '79 after an oil change too

The Cycle world test for the '79 (done on 10/26/77) says 5.8 quarts for the '79 too - Same as for all later models

http://www.cbx.com.ar/Recortes/Cycle%20 ... 20Test.htm

Don

[Mike Cecchini]

Exactly how much is "lot's more" Don ?

I've got a 79 owner near me that I'd trust with my life and he says his 79X takes exactly 4.1 qts of oil with a filter change-out........and the original 79X dipstick oi level is at the "max" mark .

What do we tell this 79 CBX owner ?

[EMS]

The 1979 Honda service manual says: "Oil capacity": Approximately 4.0 liter (4.2 U.S. qt) at change, 5.5 liter (5.8 U.S. qt) at engine assembly. The cases for the 79 and 80 models are the same. There is not a larger oil volume in the crankcase.
The oil cooler on the 79s is smaller than on the other models. In order to drain more oil from the cylinder head, you need to put the engine on the side stand for a while before the oil change, then hold the bike tilted to the right for a while.
If you change the filter, you have to run the engine for a short while in order to refill the new filter before you check the oil level.

The distance on the dipstick from the bottom of the threads to the max mark is approx 15 mm. The distance from the top of the filler hole to the bottom of the threads is only approx 11 mm. Ergo: Filling the crankcase to the bottom of the threads in the filler hole is overfilling. The crank will splash in the oil.

[Mike Cecchini]

It seems we haven't read all the posts, so I'll repeat. With my 80X on it's center-stand, I took out the oil pan drain plug and removed the oil filter canister and drained both. Then I installed new oil filter and put drain plug back in and oil filter canister back in place.

I then put 4 qts of oil in the engine and there was nothing showing on the dipstick.......nor could I see any oil in the crankcase oil fill hole.......so I went to the original 1980 owners manual that came with the bike and it says 4 liters (4.1 US quarts)....... this made no sense at all so I pulled the factory service manual out and it says 5.5 qts (5.8 US qts).

I then added another quart of oil, for a total of 5 US quarts.....started and ran the engine for 2--3 mins, some 1--2 mins after the oil light went out......waited 3--5 mins for the oil to settle and checked the dipstick...... the dipstick showed the oil level at the "min" mark.......so I added an additional 1/2 US quart to the engine and this brought the oil level up to the "max" mark on the dipstick......where it has remained after a 100 mile ride.

For clarification...... I didn't say I filled the oil level to the bottom of the oil filler hole threads...... I said..... "it took 5.5 quarts to bring the oil level JUST BELOW the oil filler threads. And usually if you over-fill an engine, especially one that turns 8--9000 rpm, this will usually blow out the excess oil as the crank stirs up the excess and it blows out the crankcase breather......which never happened on the 100 mile, 9000 rpm ride I took as I have a seperate clear crankcase breather hose with a K&N filter on the end of it as I no longer have a airbox.....so it's easy to see if any oil comes out of the enging via the breather.

All in all ..... I no longer care what the book says as I've found too many of them wrong over the years, so I check things with my own eyes and have avoided so many problems this way. Sure I check the books as a starting point, but then I question them and verify things with a large dose of common sense. So far this have never failed me and saved huge amounts of grief I see all over the net.

Now......back to the original question...... how can we say that some X engines take 4.1 us quarts on a typical oil & filter change.......while others take 5.8 us quarts on the same oil and filter change ?

[spencer]

I hear you Spence......but all I did was drop the drain plug and take off the filter housing.......and it took 5.5 quarts to bring the oil level just below the oil filler threads.

I guess I misunderstood. I thought you had disassembled the engine.

[Mike Cecchini]

Nope......just a ordinary oil change.

Back to the original question.......why is it some X's take 4 qt's on oil change and others take nearly 6 qts. ??

[EMS]

There is no evidence anywhere that the oil capacities differ from one CBX model to the other. The only exception is the oil cooler, which is 20% larger from 1980 on.
These are the 20% the "Cycle" article from December 1979 referred to. It was a road test of the 1980 model and it lists in the spec sheet an oil capacity of 5.5 liters (5.8 quarts). This was taken form the Honda specifications and refers to the same capacity number as stated in the owner's- and service-manuals for total capacity after assembly. The same goes for the "Cycle World" road test of the 1980 CBX from February 1980. It says: "An oil cooler that's 20 percent larger for 1980 helps cool the 5.7 quarts of oil used in the engine and transmission"
There is no mention in either article that this is a quantity for an oil change.
All manuals state 4.0 liters (4.2qt) for the change volume. I have U.S. and Euro model 79 owner's manuals. 79 service manual with '80 addendum, 80 owner's manual, 81 U.S. and Euro owner's manual and 81 service manual with '82 addendum
I have no doubt that one could pour 5.8 qt or more into a CBX crankcase when changing oil, but then you overfill. Period.
This is all I will have to say.

[Larry Zimmer]

OK folks, here is what it says in the Honda Factory '81/'82 manual, page 1 dash 2: Oil Capacity: 5.5 liters (5.8 US qt) after disassembly; 4.0 liters (4.2 US qt) after draining. That's exactly how it is written. What people might pour into their engines is their discretion. I offer this for those out there who might have a question and don't have a manual. What the '79 and/or '80 manual say, I don't know. Don't have one. Anyone with a genuine Honda book for those two years might do a favor and enter it here.

[Mike Cecchini]

I'm not here to quote manuals or magazine articles. I'm here to discuss reality

John Swifts 79X takes 4 qts and it's just below the "max" line. My 80 takes nearly 6 qts to reach the "max" line. I thought it rather interesting and not something only I have discovered in these 30+ years of CBX existance.