Running extra oil


7 replies to this topic
  • bigred455

Posted August 12, 2008 - 10:09 AM

#1

If you really think about it,a qrt of oil for both tranny and motor is nothing.Especially smoking up a track,which I do not do any more. I always run 34 ounces with or without filter change. I drop the oil every 2 rides about 3 hrs. Since oil is constantly being circulated through Yamaha's design and it has a tank,I wonder how much added oil can the system take without having the crank being flooded with oil? Will more oil cause more pressure than the seals can withstand? How bout drag on the crank with more oil? After the motor is stopped the oil drains out of the tank so the tank will not be overfilled.I love maintaining my bikes as much as riding them,infact I get warm and fuzzy inside after a filter and oil change.:)

  • DougWood

Posted August 12, 2008 - 10:18 AM

#2

Extra oil is most likely just going to come out of the vent hose. It will cause extra resistance inside the engine. The engineers designed the engine to contain enough oil. If you're worried just change it more often and make sure you don't run low.

  • bigred455

Posted August 12, 2008 - 10:24 AM

#3

I change it every 3 hrs that is very suitable, infact I never would go longer between change. I am very aware of the level in my bikes.Not the answer I was looking for,but thanks for the reply anyway.

  • matt4x4

Posted August 12, 2008 - 11:24 AM

#4

Depends how much more you want to add, 50-100ml more and I don't think that it would come out the breather hose, aside from having more oil, the pump still pumps at the same rate it did before adding more oil, which means the lines still contain the same pressure and move the same amount of oil so the oil delivered to the head and all other portions of the bike should remain constant, the sump and the frame tank may be holding more oil since these are your "excess oil" storage locations - it's a continuous system that only interrupts when the bike is stood up on the rear end and the oil normally available at the pickup is no longer available, but rather collecting at the back of the case, this is why it's got a tank in the frame - to continue supplying oil during those short periods where the pumping system may be interrupted.

Since the head has a breather and the cam chain slot is open to the bottom end, the system is not under any great pressure (it pulsates at the breather), the only time you'll have pressure possibly blowing out seals is when the breather tube is pinched off (which has happened to some) and the seals that pop out are the half circles at the head since they are your weakest link.

I run the specified amount of oil and still get drips out the breather (wr400F) because the breather will get wet from the oil mist blowing in the head, once the mist coats the inside of the tube it goes where gravity wants it to go - which is down the tube to splatter out the bottom.
Of course, if you put in WAY too much oil........different outcome.

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  • bigred455

Posted August 12, 2008 - 01:08 PM

#5

I have the 07,my tank is internal,I guess I can keep adding 2 ounces from 34 ounces at a time. I will just keep a eye out on the breather tube ,see if it starts to weep. Of course after I add oil I will test hard and see if the tube starts puking. As of right now 34 ounces is what I have been running from the begining and the tube shows no weeping.I will move it to 36 ounces.

  • grayracer513

Posted August 12, 2008 - 02:31 PM

#6

In a dry sump system, the amount of oil in the tank has no direct bearing on the amount in the sump, UP TO A POINT. It depends on the capacity of the tank to carry more than the prescribed amount. When this capacity is exceeded, the additional oil being scavenged from the sump and returned to the tank will no longer fit, and the extra is forced out the oil tank vent and back to the engine sump. Depending on the amount of the excess, this can lead to oil out the breather, oil past the rings, etc.

In a 426, there was room for about 200cc over fill before trouble started. In the steel 450's, the oil capacity listed was lowered, but the tank itself was never made smaller, and even though it called for 1.2 qts, you could easily run 1.5.

The '06 is another matter. it has, for all practical purposes, NO EXCESS CAPACITY. Any extra oil beyond one or two ounces will be forced out teh pressure balance and back to the sump.

  • swatdoc

Posted August 12, 2008 - 03:27 PM

#7

I have a clutch cover on my 07 made by STB that is wider and therefore holds 120cc extra oil. not a lot, but every little bit helps.

  • grayracer513

Posted August 12, 2008 - 04:25 PM

#8

I have a clutch cover on my 07 made by STB that is wider and therefore holds 120cc extra oil. not a lot, but every little bit helps.

They say that, but in practice, it doesn't work. Here again, it's a dry sump, and the return pump will draw down the oil to the bottom of the sump screen as long as it has somewhere to put it. When the tank capacity is exceeded, it's forced back to the sump, all the same.





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