Question on oil volume in crankcase

[blackheart]

I'd like to poll those who change their own oil.  The tricky part of this question is whether before draining oil, was the bike run at 2500 rpm or so for the required 30 seconds prior to check.

My question is what is the normal volume of oil in the crankcase (front oil plug) that you observe when you change oil?

I've only changed my oil 3 times in the approximate 8k mile I've ridden it.  I was always surprised at the amount of oil in the front sump.  The last few times I changed oil I did the raindance as everyone calls it just to make sure I was not having oil layout somewhere I couldn't drain.

When I recently had to pull the top end on mine #307, I was surprised to see visually how much oil was actually in the crankcase.

So, if anyone cares to answer how much do you observe and do you or do you not perform the rain dance prior to doing an oil change?

Rich

[Donkey Hotey]

Rich,

The rain dance shouldn’t matter if you’re changing the oil and pulling both drain plugs. It should all drain out if the bike is upright. When you pull the two drain plugs and hold it vertical they are the lowest points in the sump (assuming you just rode it to warm the oil—don’t warm the oil on the side stand).

The rain dance is intended so the scavenge pump can clear all the cavities of trapped oil and return it where it’s normally stored (the transmission sump) before checking. If you topped off with extra oil trapped somewhere, that’s how you end up with an overfilled engine.

Personally: before checking oil level, I ride it around the block, then shut it off before putting it on the side stand. Wait a minute or two. Check the dipstick. If I’m refilling after an oil change, it’s usually 3 quarts “and a little” then I ride it around the block and check. Repeat until I’m satisfied.

Have you owned Harleys? You kind of do the same with them: before checking oil level, you’re also supposed to run them for a minute or two. In their case it’s because the check valve on the engine doesn’t always hold. Some of the oil can drain back into the crankcase. The scavenge pump needs to return that oil to get a correct reading.

And now for my controversial argument that nobody liked when I said it almost 19 years ago: our bikes are a similar dry sump design to a Harley. The difference is that our “oil bag” is the transmission case. Our transmission and clutch share oil supply with the engine but as far as the crankcase is concerned, it’s still a dry sump design. By definition: a wet sump would store its oil in the sump (crankcase) and ours don’t do that. If a scavenge pump moves the drain back oil to another place and it can’t return without the oil pump putting it there, it’s a dry sump.

[Donkey Hotey]

Just because I like beating these subjects to death. 



While riding down the road, the oil gets stored back in that transmission cavity, noticeably uphill from the primary case we’re staring at here. If the oil isn’t in that transmission cavity, it doesn’t get measured on the dipstick.

The job of the scavenge pump is to take drain-back oil from here and get it back “over there.”  The oil sump scavenge tube that is part of our needed upgrades is an extension to that pickup point. In this photo, it’s one of the holes at the base of the primary case wall.

The “trapped oil” and inaccurate measurements happens on the side stand; that hole becomes uphill from the rest of the primary case. It turns out that a lot of oil can accumulate in there (idling on the kickstand) that never shows up on the dipstick.

[wytfut]

Rich....
     I've always have gotten about the same amount out that I have put in, on all the X's I've changed the oil in. Of course, its never exact... but close enough not to worry... I do not purposely go out of my way to do the dipstick dance, or warm up the engine when I do an oil change. Mostly because I do it in the winter, and while my shop is warming up so I don't have to wear gloves, I'm moving 525 to the lift. I'd say with gravity and time working, I still get the same amount of oil out of the case as if it were all warmed up. I'll let it drip for an hour sometimes...
      Years ago, I was moving on a "4 quart" side project on my X 525. One of the community members came up with a process that will let the X hold 4 quarts easily.... more about that in a bit...
       When tackling this, I mentioned to Jamie, I just wanted to be able to get 4 quarts in my X without it puking all over.... sort of a OCD thing....
      Jamie replied that the X's are actually a 4 quart engine... but you'll never get the last quart out. Every X motor he has torn down  has always had an amount of oil in it....     
       I've also found that each X that I've been around, the total amount when changing, can be a bit different from X to X.  Our DWS, you couldn't put hardly anything oil in it over 3 quarts.... it was a puker hard core.  525 was more tolerant closer to 3 quarts and 4 oz. ... Where as old Blue you could push sometimes to 6-7 oz.
      All of this for ME, just validates the personal idea that these bikes are actually prototypes. That yes they were built in standards, but they each have their own nuances. I can give more examples......
     Greg, as for the dry sump theory.... I hadn't ever looked at it that way, .... I agree...    the dipstick dance in its self explains that....
     I've mentioned this many times, and feel I have to bring it up, as I know there are owners out there that believe different.....   The Bobby Xman Baldwin site glass trinket is a poor at best way to tell how much oil is in your motor. I had an issue, and the site glass said it was full.... it was not full, my case barely had a quart in it.... ..

As for the 4 quart project that I did....
I think, I'll put it on another topic, as I like these posts to be nice quick reads....

[wytfut]

and a little bit more just to confuse everyone even more...

In theory, if you read what I quoted Jamie....
On 525, I'm actually running probably closer to 5 quarts of oil after an oil change....

[blackheart]

I agree with what your saying except cant fathom why you cant run 4 qts.

On this POS I got, whenever I get it to stop smoking like a locomotive,  with a dry engine it took closer to five quarts, certainly 4.5 after running to show in the mid point of the xxxx range on the stick.  I used the original hose for dipstick upon assy.

I agree,  with bike vertical the crankcase drain gets most all oil out of the crankcase.   The primary is tied to the sump via a hole in the bottom, so even if oil is stiff, if as you say you let it sit for hours it will drain most of it over to main sump and out the hole.  This is why it makes no sense to run a pick up tube which pulls oil from an elevation lower than running oil level in the main case as essentially you are overloading the inner scavenging pump. 

I've always felt I'd rather not have any extra oil  pick up tube for the simple reason if I can increase the residence time of oil in the primary it has more time to be blown, thrown, and sloshed around thus  contacting the primary cases cover and housing effectively increasing the heat rejection to atmosphere.

The oil that cannot drain is that caught in the cam chain drive side and that in the oil pump supply side. 

As for a sight glass on the oil supply pump cover, it would never be possible for it to show oil level relevant to the main case.  I'd think it's near full at all times at least as high as the spillover to the cam case

[wytfut]

well..... hopefully I'm not misinterpreting what you are asking Rich...
And I realize that you are one of a few of the X's out there that does not puke... why I don't know, anymore than the X's that are habitual pukers...

From what I understand, the engine design will hold by volume 4 quarts...   from completely empty on a fresh motor.
This is why you got 4 quarts in yours plus .5 more, on your fresh motor.

But on most Xs, .... it will not fully drain that last (#4) quart on an oil change. So when I do an oil change, I cannot add a full 4 quarts. You can add 3 quarts and a partial, according to your specific X.

This still tallys up to 4 quarts + by volume, as you havent' totally emptied your crank case orignally.

Reasons being, anything over 3 quarts + added to engine with a confined quart hiding, the X will puke it out.
Most X's will puke out anything more than it can handle....    usually around 3.5+ quarts...

As for the pick up tube... 
Way back.... there was a VHS video made .... and in that VHS, Bobby XMan Baldwin had a part where he proved to the engineers at the factory, that we could not warm up our X's properly, on the kick stand. He hooked up a mechanical oil pressure gauge in the sending unit port, and started an X on its kick stand...
The guage would jump and fall, all the way to 0. Thus proving that X's on their kick stands were cavatating air.  And he felt that maybe even in heavy cornering it would. So he designed a pick up tube.  superXparts also did.. for the same reason.
I saw the video.... and it still leaves quite the impact on my itty bitty head. ... oil pressure of over 60 pounds, and then flop down to 0,.... back and forth...   

[blackheart]

So I can see where, on the side stand the X-twin can and will transfer too much oil into the primary case,  more than can flow by gravity back into the sump under the transmission.

I've always heard about the puking deal so I just habitually wont run the thing on the side stand.

But, this whole thing got me to thinking again so I'm going to check out #204, the partial engine I bought for a spare.  What struck me a little off when I was into my bike, #307 and machining the cases for new main bearings was the engine case side of the scavenging pump pulls from a cavity under the crankcase.  This sump area has a crank scraper above it, which makes perfect sense.   But what I never thought of was that extra hole into the sump coming from the other side or left side.  This is the one which goes over to the primary.   By the original design the clutch basket driven gear pushes or tries to by theory, oil up to this hole.  So in my mind this hole has oil coming in and possibly blowing out at times during piston decent.  This statement assumes the reed valves cant effectively relieve all pressure, but who knows.  So maybe the extra tube prevents or slows this down.  But if you think about it, the dip tube on the left side doesn't directly connect to the scavenging pump & why would it preferentially pull oil from the primary?  After all it pulls from the cavity under the main case. So it must be and actually this makes sense this diptube port pulls oil in on the upstroke.  So combustion gases get blown to the primary via the reed valve ports, the oil separates out and flows either by gravity to oil sump under transmission or get sucked into the area under the crank.   So in my mind the extra diptube keeps solid oil and/or less aereation in any oil getting sucked into the sump under the case for the scavenging pump to pick up.  Oil level must go down in primary when diptube is installed.   So how do combustion gases get vented over to transmission and ultimately back behind it to eventually get out?  I have never thought about that until now.  I'll have to see what paths are available but there must be some!