Question for DRY SUMP GUYS



16 replies to this topic
  • Shawn_Mc

Posted June 25, 2002 - 12:09 PM

#1

All you guys that have done the drysmup mod:

Have you noticed that your clutch works smoother now?

The reason I ask is, if the clutch doesnt get enough oil and the motor is dry sumped, how much is the clutch loving have an oil bath? I would think the clutch would be buttery smooth in an oil bath.

  • Shawn_Mc

Posted June 25, 2002 - 12:10 PM

#2

I meant WET SUMP!

Gees ya dry sump one camaro and that all you can think about!
Man, that car was trick.

  • DaveJ

Posted June 25, 2002 - 05:23 PM

#3

ShawnMc,

I think you're under the impression that there is more oil in the crankcase with a wet sump than a dry.

Going from dry to wet means removing the oil that is circulated through the frame, but you still have to account for the remaining quantity that remains in the case regardless of dry or wet configuration. Unlike your Camaro.

So you shouldn't notice any clutch differences, nor have I felt any post my conversion.

However, I don't think Yamaha built in a thermostat on this bike, meaning that the oil in a wet sump conversion will come up to proper operating temp sooner, therefore pro-longing engine life compared to those riders that fail to recognize how long it really takes to warm up the factory amount of juice.

And of course a warm clutch works better than a cold one.

DaveJ

  • DaveJ

Posted June 25, 2002 - 05:24 PM

#4

[ June 25, 2002: Message edited by: DaveJ ]

  • Shawn_Mc

Posted June 26, 2002 - 12:21 PM

#5

DaveJ Im not calling you a liar, but if what your saying is true about the WET SUMP, VS. THE DRY SUMP is the oil level is the same, and I dont think it is. There shouldnt be an oil level in a dry sump motor, hence drysump. Whereas the wet sump does, on the simple fact that the oil has to be stored somewhere. This is furthered by the recommendation of running the engine for a few minutes before checking the oil level. After sitting the oil level drops as the case fills with oil from gravity. I dont know how much oil it takes to fill the lines to and from the resi, and the resi. itself, but it would seem like more than 800-1000cc's.

The reason I ask, is my clutch is a grabby piece of crapp, unless I sit there with the clutch in for 20 or 30 seconds before I take off. It doesnt make any difference if the bike is in gear or not, just as long as I hold the clutch disengaged. Which tells me it wants more oil. Now we both know 20-30 seconds isnt enough to warm up the oil, but the difference in clutch action is 1000%. It goes from snatchy grabby to buttery smooth. Ive got a hinson basket and hub, with EBC plates, both are like new. And its been like that since install.

Davej, do you have a sight glass for the oil level in the engine? Im just curious, where in the engine they wetsump mod carries the oil. I cant believe they just let it fill the crankcase portion of the bottom end.

  • newmann

Posted June 26, 2002 - 12:35 PM

#6

The Dubach kit has a sightglass that replaces the neutral harness by the shifter. On the 250F with 850cc of oil the oil level will be right in the center of the glass.

  • techman

Posted July 06, 2002 - 12:03 AM

#7

I think a reasonably well known solution for the grabby clutch is to take out one stock fiber plate (most inboard, against the inner basket face) and replace it with an 01 inner-most fiber plate plus spring plate plus steel backing plate combo. It will make your lever mushy but that can be changed by also changing the actuating arm etc for a different throw ratio down in the cases. I personally just live with the mushy engagement.

  • John_Lorenz

Posted July 06, 2002 - 04:25 AM

#8

Im curiuos
Shawn I know you have an 00, I do also, my clutch is grumpy, grabby and cranky until at operating temp. I am told this is normal. You also say you have the hinson and plates replacing the stock.

Here is what I am curious about:
I thought that the 00 fix was a either a 01 bascket or what you have done! If it is not a fix then I would assume that the oil conversion would not make a diff in the clutch. I dont know thats why I asked. I also dont know enough of the dry sump wet sump to respond on that.

I only posted becouse you asked
ShawnMC Wrote

The reason I ask is, if the clutch doesnt get enough oil and the motor is dry sumped, how much is the clutch loving have an oil bath? I would think the clutch would be buttery smooth in an oil bath.


It was just confusing

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  • moto2000

Posted July 06, 2002 - 06:13 AM

#9

Do as Techman suggested and update to '01 parts. It will get rid of crappy engagment.

  • DaveJ

Posted July 06, 2002 - 08:43 AM

#10

Shawn,

So yes, I think the operating oil level in both the wet and dry configurations are nearly the same.

Mainly because the oil capacity of the frame and lines are equal to the amount of oil you don't use once the conversion is made. In other words, 52oz minus 800 to 950ml is what sits in the externals.

And I think the issue where you have a lack of an oil level reading when the bikes sits for extended periods, is the result of oil sneaking past the check ball valve and filling the case with more oil than operating level.

However, I never really proved any of this so I'm open to anything with a little more evidence.

DaveJ

  • Vanilla_Gorilla

Posted July 06, 2002 - 11:14 AM

#11

in the dry sump engine, there is little oila t the bottom of the crankcase, just enough to keep the pump form sucking air into the lines. with a wet sump, the clutch will ahve much more oil to work with, and should make it feel much smoother. however changing oil after evry ride is a pain in the arse. BTW, i know this because some of the deisel equipment i repair at work is dry-sump, so i have some experience working with those. Im thinking about wet sumping my enigne, but changing oila fter every hour? c'mon!

  • Hick

Posted July 06, 2002 - 01:55 PM

#12

Originally posted by DaveJ:
Shawn,

So yes, I think the operating oil level in both the wet and dry configurations are nearly the same.

Mainly because the oil capacity of the frame and lines are equal to the amount of oil you don't use once the conversion is made. In other words, 52oz minus 800 to 950ml is what sits in the externals.

DaveJ


Yes but on the stock dry sump setup there are two separate pumps operating, one impeller type and one star type, the latter returns oil to the res., the former is fed by the res. and delivers oil to the bottom end, head and tranny.

So, unless the star pump delivers more volume than the impeller pump the latter could eventually starve as it fills the cases, emptying its own reservoir. So it seems logical that the star pump “outpumps” the impeller pump, and that the static oil level in the cases therefore hovers around the level of the oil pickup.

Or maybe not.

Easy way to find out is plug up the reservoir delivery line and fill to the line on the dipstick, measure that amount & subtract from 1.7L and that is the amount in the lines and cases, but I would bet that the sump can hold most if not all of the 1.7L capacity.

When they say the 450 is getting the same oil pump as the 250F I wonder which pump they are referring to?

  • holeshot

Posted July 06, 2002 - 03:23 PM

#13

Originally posted by techman:
I think a reasonably well known solution for the grabby clutch is to take out one stock fiber plate (most inboard, against the inner basket face) and replace it with an 01 inner-most fiber plate plus spring plate plus steel backing plate combo.


I'm using just the '01 inner-most fiber plate (because the steel backing plates have problems with the Hinson inner hub).

Clutch operation is smooth using just the one part, and no "mushiness". If were running the stock inner hub, I'd run all three '01 clutch parts, just to be on the safe side......

[ July 07, 2002: Message edited by: holeshot ]

  • DaveJ

Posted July 07, 2002 - 09:50 PM

#14

Hick,

I don't think there should be a supply battle between the two pumps, since both are circulating a fix amount within their own regions. A loop.

In other words, there is never more oil leaving than what is returning, (except for when the bike has been sitting for extended periods).

Or did I not fully understand your issue?

DaveJ

[ July 07, 2002: Message edited by: DaveJ ]

  • Hick

Posted July 07, 2002 - 06:21 PM

#15

Originally posted by DaveJ:
Hick,

I don't think there should be a supply battle between the two pumps, since both are circulating a fix amount within their own regions. A loop.

In other words, there is never more oil leaving than what is returning, (except for when the bike has been sitting for extended periods).


DaveJ,

One pump empties the cases and fills the res, the other does the opposite.

If there is never more oil leaving than arriving, how does it empty the cases when the bike has been sitting? How does the inner pump “know” to pump more in this scenario?

That is a rhetorical question, and one that leads me to believe that the inner pump has a higher capacity than the pressure (impeller) pump to ensure the latter never runs out of oil.

So, once the bike is running for a few moments things stabilize, then there is an equal amount being pumped by both. But since one out pumps the other this static oil level will always be somewhere around the inner pump’s pickup.

That is my theory, anyway. I always assumed the wet sump would therefore have more oil in the cases, because by design it has to gravity flow to the pump...

If you can think of errors in my theory let me know.

  • DaveJ

Posted July 09, 2002 - 10:40 AM

#16

Hick,

Sounds good to me.

Perhaps the next time either one of us is in there we can take a closer look are answer this one out. I'll bet your theory proves correct.

However, any thoughts on how much is remaining in the frame?

Most wet sump conversion seem to remove 20 to 25oz of oil.

DaveJ

  • Shawn_Mc

Posted July 09, 2002 - 12:27 PM

#17

The scavenge pumps draw more oil than the supply pumps pump. If they didnt the supply would dry up, and the engine would run with an increasing oil level. The scavenge pumps are usually different types of pump also. Scavenge pumps dont normally provide very much pressure. Just enough to refill the resivoir.





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