Rear diff oil level

I just did an engine oil/rear diff oil change and I noticed that when the rear wheel is rotated the oil level fluctuates...is 200ml correct at the low point of the fluctuation, or at the high point?

I thought the 200ml should have been approximately where the oil is high enough to just meet the bottom of the filler hole (when the bike is level of course).

?

Fill the rear drive until it is just to the lip of the hole (on the centre stand). Do NOT rotate the wheel and add more as the level goes down. It will be over-filled and probably work its way out the vent. (Might cause pressure buildup compromising the rear seal to the pumpkin although I'm not sure if that is possible with the vent system.) Don't rely on a measured volume either - no need and volume required will depend on how much oil drained out.

CollingsBob said:

.is 200ml correct at the low point of the fluctuation, or at the high point?

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200ml is 200ml. It doesn't fluctuate. If you want to get that amount...measure it in a graduated cylinder.

Or do like everybody else and fill to the bottom of the drain hole as #2 Cyclepath noted first and don't rotate.

I use the Yamaha magic juice. I pour it in a regular gear oil bottle with a needle nose to make it easy to squirt. Fill to the brim, no spin. I spun the wheel and put extra in once. It didn’t hurt anything, it was just a waste of magic juice.

had a friend who used to use an eyedropper to fill it....used to measure out the cream for his coffee too..

Here you go, one pumpkin perfectly filled (or maybe 1mm too high). No turning, which is how the factory does it.

(Click on image for larger view)

^^^

Yes - to the lip and no wheel rotation. As with engine oil, trying for an exact specific volume is senseless. And quite possibly wrong depending on how effectively it drained before filling (affected by temperature, fluid viscosity and your patience!). Nothing to say that the internal volume is absolutely identical between bikes either.

Mcatrophy - your bike needs a bath!

Ok, I gotta ask..why the dire warnings against rotating the rear wheel?

CollingsBob said:

Ok, I gotta ask..why the dire warnings against rotating the rear wheel?

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Rotate the wheel all you want. Just let it settle out before you put the fill plug back in.

When you rotate the wheel, the fluid level drops significantly as it coats surfaces that are normally above the static fluid level. As John d says, no problem with rotation as you fill but let the level settle (and overflow) before putting the plug back. Tidier to simply fill to the requisite level. That is the correct amount of fluid as per Yamaha.

RossKean said:

...Mcatrophy - your bike needs a bath!

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Well, yes and no. It had just had a sort of bath .

(Click on image for larger view)



Ride posted up here.

Yeah but if I do spin it will it matter if it's clockwise or counter clockwise????

mech 1 twa said:

Yeah but if I do spin it will it matter if it's clockwise or counter clockwise????

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That depends on what tires you're using.

If its a car tire, then youre really going to suffer an aluminium and plastic death for sure!

Brodie

I'm using one just like this...

mcatrophy said:

Here you go, one pumpkin perfectly filled (or maybe 1mm too high). No turning, which is how the factory does it.
(Click on image for larger view)

Click to expand...

Mac is spot on. Officially it is to be filled to the point of overflowing. Why in hell do you want to turn the wheel? Do you start the engine and check the oil level?

did that once on my FJ1200...forgot to put the filler cap back on....had oil dripping off the ceiling..

mech 1 twa said:

Yeah but if I do spin it will it matter if it's clockwise or counter clockwise????

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I'm guessing your just joking around but yes it does matter. I used to be that guy that always had to put a little extra in. if you turn the tire counter clockwise (forward) the correct amount will come out the fill hole and you will wind up short. If you turn the tire clockwise ( backwards) the fluid level will appear low and you can put a little extra in. Putting a little extra in never created any problems for me but others have reported oil coming out the breather on top and making a mess. Now I just fill to the top of the fill hole and give it a quick reverse spin so I can put the filler plug in with out forcing more oil out.