Should oil level be higher for oil cooler?

TexasKZ wrote: According to the FSM supplement for the KZ/Z1100B, an extra 0.2l should be added for the cooler. That is about 6.8 ounces.

Thanks, Texas!

zed1015 wrote:

Nessism wrote:
One other question I have is do the later bikes with coolers have the sightglass window a little higher up compared to the older bikes? I've looked at the 750/4 model bikes and the answer seems to be NO, but that's just based on photos I can find of the engine cover.

The oil sight glass is the same height and position on all z650 and Z/GPZ 750 fours and 750 Zephyr although the 750 zephyrs sight glass is a larger diameter.
The GPZ and Zephyr have a coolers fitted yet share the same oil capacity as the non cooler models at 3.5 litre and so does the GPZ750 turbo.

I'm a little embarrassed by my question since I've already looked in the service manual and noticed that Kawasaki did not increase oil capacity for the cooler equipped bikes. Bottom line is that the oil level in the sump will be lower while running for a cooler equipped bike, but apparently the oil level is still sufficient to fulfill the needs of the bike so no worry.

Looking at the ZR-S manual shows that Kawasaki bumped the oil fill from 3.5 liters to 3.6. The ZR-7 cooler is quite large though so that may explain the difference. Wonder how they do that though if the sight glass is in the same spot as the earlier bikes?

The oil pans are different.

When I mounted cooler on my Z many , many years ago, instructions said to add extra oil to compensate for the cooler. If I remember correctly , it was about half a quart. This was to compensate for oil in the lines and cooler while running. I've never had any problems with the extra oil. On the other hand, I've been told by a few mechanics that you can run a Z with a little less oil then called for to keep it away from the crank, but I still prefer to keep level up. Some have told me to keep it down to around 3 1/2 quarts but that sounds low to me. Maybe that is what racers do, but not sold on that idea for the street.

Guys this is a non issue, just keep the oil between the oil lines in the sight glass with our without an oil cooler. Your way overthinking this.

Nessism wrote:

zed1015 wrote:

Nessism wrote:
One other question I have is do the later bikes with coolers have the sightglass window a little higher up compared to the older bikes? I've looked at the 750/4 model bikes and the answer seems to be NO, but that's just based on photos I can find of the engine cover.

The oil sight glass is the same height and position on all z650 and Z/GPZ 750 fours and 750 Zephyr although the 750 zephyrs sight glass is a larger diameter.
The GPZ and Zephyr have a coolers fitted yet share the same oil capacity as the non cooler models at 3.5 litre and so does the GPZ750 turbo.

I'm a little embarrassed by my question since I've already looked in the service manual and noticed that Kawasaki did not increase oil capacity for the cooler equipped bikes. Bottom line is that the oil level in the sump will be lower while running for a cooler equipped bike, but apparently the oil level is still sufficient to fulfill the needs of the bike so no worry.

Looking at the ZR-S manual shows that Kawasaki bumped the oil fill from 3.5 liters to 3.6. The ZR-7 cooler is quite large though so that may explain the difference. Wonder how they do that though if the sight glass is in the same spot as the earlier bikes?

The answer has to be yes, you should run the extra oil that the cooler holds, if the setup you have drains back into the sump. Otherwise it will be like running your oil low in the engine. Running lower most likely won't cause any harm, but who would knowingly always run their oil on for example the lowest mark on your oil window or on a dipstick?. There is likely quite a range over which the oil pump is still fed and everything works fine from a critical low, to a critical high. Unless you have a very big oil cooler then no one is likely to suffer a failure by not adding extra, but I would still do it, it's useful to have the extra oil capacity anyway. The other thing is if you are running at the lower level that's fine, but should you get some sort of leak and lose oil you have less safety margin, time to stop etc. before damage occurs.Personally however, I'd still be more concerned with how long the cooler takes to fill again each time it's drained down.

For the factory setup on the 1100, we are talking about slightly over 3/4 cup of oil. Assuming that 3.7l will put the cold level somewhere near the middle of the sight glass, I doubt if that extra little bit would even bring the level to the top mark. In my own, limited, slightly ignorant opinion, keeping the level toward the upper line should meet factory specs, and I am fine with that.
ymmv

I always wished I had a dip stick on my bike. If I had one I wouldn't have lunched a piston. The sight glass was so dark, it was hard to see the oil level. My fault, I should have cleaned it but I hate the idea I have to depend on it.
Steve

Guys this is a non issue, just keep the oil between the oil lines in the sight glass with our without an oil cooler. You are way overthinking this.

Agreed, for example some of the 550 models which share the same sump pan and clutch cover window were equipped with cooler, others not.

I would love to make a funny about the dip stick on the bike but I digress. I have always kept my oil level at the middle of the sight glass as any more seems to burn off and then stay in that position. I've 10,000 miles on a fresh motor and seldom add oil other than in the middle of the summer with my own concoction of blends, and it stays clean. I found an original factory cooler and when I do an oil change I still leave it at the center of the window. I have a friend with a 1327 J motored drag bike who keeps half a quart in the crankcase to lessen crankshaft web drag for about 3 min. of warm up, a burnout and 8,4 seconds down the track with no issues, ever. Check your oil through the window after being on the center stand when cold and don't overfill as zed1015 advised and this tractor technology engine will outlast you!

swest wrote: I always wished I had a dip stick on my bike. If I had one I wouldn't have lunched a piston. The sight glass was so dark, it was hard to see the oil level. My fault, I should have cleaned it but I hate the idea I have to depend on it.
Steve

Your engine is as dirty as the glass. Flush it.

That was 2 1/2 years ago. I cleaned it with a Q tip and carb cleaner.
Steve