Question about foaming

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Nikolas

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I have recently bought a used Kawasaki ZR-7. The engine is a fairly low tech air cooled DOHC I4, 2 valves per cylinder. I took it to the local bike shop for some minor work and they threw in a free oil change, presumably with some m/c specific 20w-50. I covered about 3k miles on it, there was some minor consumption (about a pint over the OCI) and I changed the oil. I used some Castrol Tection 15w-40, API CH4 rated, because I have lots of it lying around. By accident I overfilled it by less than half a quart, on a total capacity of about 4 quarts.

Now I don't mean to start a heated debate about HDEOs in motorcycles (you know... your clutch will slip and your hair will fall off
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). However, I noticed a couple mm's of foam through the oil level sight glass, right after switching the bike off. After it sits for half an hour or so the foam goes away.

My question is whether this is caused by the slight overfilling (about 10% of total) or is it something specific to different additives in HDEO. Other than the foaming issue, the bike is running sweet, and the gearchange improved slightly. Any and all input is appreciated. Thanks!
 
Out if curiosity, I measured the height of the excess amount of oil present, it appears to be about 3 mm. Is that enough to make a big difference in the amount of the crank whipping the oil?
 
Originally Posted By: Nikolas
Out if curiosity, I measured the height of the excess amount of oil present, it appears to be about 3 mm. Is that enough to make a big difference in the amount of the crank whipping the oil?


Yes, it is possible.
 
I have a GSF 1250 Bandit and I always have a little foam on top of the oil in the sight glass right after I shut the engine off, but after a couple of minutes the foam is gone. At first I thought it was the oil I was using (HDEO) so I tried different HDEO's but the results are the same even if the oil level is a little high or low so I decided it must be normal to have a little foam on top of the oil right after engine shut down and I quit being concerned about it.
 
Thanks for all the replies. I will keep an eye to see whether the foaming reduces as the oil level is getting lower. Is the foaming something that has to do with the chemistry of HDEOs vs m/c specific oils? The reason why I am saying this is because I didn't notice any foaming with the m/c specific oil.
 
I had an RC 51 and I noticed the same thing if I looked at the site glass right after shutting off the engine no matter what kind of oil was in it...Didn't matter if it was Mobil MX4T "motorcycle oil" or Mobil 15W50 red cap that was popular...I always put the exact amount the manual called for and it made no difference...

Same thing with my Bandit 1250...It did it with the oil that came with it off the show room floor (probably "suzuki performance 4"), the Castrol motorcycle oil, the Valvoline motorcycle oil, and the Shell Rotella 15W40 I started using at about 1,000 miles...I've got over 14,000 miles on it now and currently using Delvac 15W40 and it does it..Each time putting as close to the exact mount the manual calls for even using a measuring cup at times...

The bubbles I notice are usually gone after just a minute or so...
 
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