TOPIC:

So after my rebuild I have been looking into what oil to run. Being a high reving air colled engine the oil formulation is a bit more critical than in most applications. For my break in period I am running Yamalube 20w50 but need to change it soon. I will run a few hundred more miles, change it, then change the oil again in the fall. Then it will be regular intervals.

Looking at some UOA's (used oil analysis reports) on websites like this...

www.bobistheoilguy.com/forums/ubbthreads...=1242718#Post1242718

I found that OEM oils like Yamalube and Kawsaki's oil are no better than the chaep stuff at wallmart. And synthetic oil needs the same change intervals as pure conventionals. The problem I found is that motorcycle engines in general shear oil and break down its viscosity. In some reports in a matter of hours 50W oil had been reduced to less than 30w.


So what are the best oils for these engines? Is ZDDP (Zinc and Phosphorous) nessesary? How about addatives for the clutch? Has anyone here ever had a UOA done on thier KZ?

So sound off everyone, what oil are you running and how often do you change it?

I have run Castrol 20w50 in my 440 and 650 prior to rebuild, I change once a season.

Penn Grade 1 20W50...just bought a case...but haven't run it yet...high in ZDDP.

I have found that motorcycle specific oils perform better that automotive oils. Shifting get notchy and the clutch gets spongy when using automotive type oils.

Belray 20/50

i built industrial engines as a job for several years and a few hundred rebuilds.i never could tell what a customer ran as far as type of oil,but i could tell if they changed it regularly.with wet clutches you need something that will work with that beyond that buy whatever makes you feel good and change it at regular intervals.
the main thing being change it at regular intervals.

leon holmes

I have not an idea for real but... I ran Castrol 20w50 in my 79 with 5,000 miles on OD and I can say that I changed the oil very frequently. She began to smoke after a year.
I got a bike from California with 7k on odometer with a blown head gasket and have seen the difference. This bike was run with motorcycle lubricant. Didn't smoke at all. Excepting the blown head gasket from being overfilled with oil I would have left it alone.
There are lots of parts inside that wear, dry out and crack when regular oil is used so I have been told. I saw the difference with my own eyes when we took down my 80 ltd.
Motorcycle oil is supposed to be formulated for all those parts moving gears anti-sheer formula and the clutch. I believe it is. This engine after 29 years looked new. The valve guides didn't need to be messed with, the cylinder walls were like new. I regretted taking her down to replace the pistons with a 1075 kit. I still regret it in a huge way although I really love the power I have now although I could have saved it for the 79. All I needed to do was to replace the head gasket and clean up the head while I was at it I would have had a great bike. She screamed for being stock. I stayed side by side with a guy that had a 1200 and mtc lock up clutch in his bike. No matter what he couldn't pull away from me.
I believe honestly that you get what you pay for and with bike stuff you pay a little more but it doesn't stand to reason that everyone would lie to you about the motorcycle oil being the same as automotive oil. I just can't believe it. My friend who has drag raced bikes and tore down many a kz motor has told me that without a doubt he can tell which bikes have used quality oils and which have used automotive oils. I don't for a second mistrust his ideas about using good oil and I think you can see it any way you want but it might behoove you to trust that motorcycle oil was designed for motorcycles specifically.

Just to add to the question. Why don't you check out the whole slew of comments previously commented on concerning which oil is best. I think you will find that that particular thread is highly informative.

Kawasaki 20W50 oil, Kaw 10W40 in spring and fall. My 550 does not shift as well with the lighter weight oil and clutch action is not as good either.

I switch around so much, but in the last 35,000 miles I have mostly used Castrol 10w-40 and 20w-50 car oil, then Shell Rotella 15w-40 (in there now), Valvoline 10w-40 motorcycle oil, Kawasaki 10w-40 motorcycle oil, Walmart Accel 10w-40 SF grade, Pennzoil 10w-40 Hi Mileage semi synthetic.

The key is change it often and it probably doesn't matter much what brand it is.

34 years of castrol 20w50 in the summer, and castrol 10w40 below 70F. My Z1 still runs like a champ with no major motorwork since day one.Everyone else is right that you can surely see the benefit from regular intervals. With the seasonal change, living in hot, humid Virginia, mine gets changed right around every 1000-1500 miles. Additionally, I've always been in the practice of changing it before, and directly after the seasons first startup. You can tell a world of info simply by doing this. If it comes out clean after the seasons first start, you should be in good shape. If there's any discoloration, you could be looking at shotty pistonrings or other internal issues. Any flakes at all, well, then looks like you might be hunting down something more serious.

Most 'Z9/1000 riders i know use the recommended castrol GTX (10/40 or 20/50 depending on time of year) although i've been using silkolene super 4 10w/40 all year in my Z1R for 9 years now with no problems. Currently got GTX in the Drouin project for the initial start ups and breakin then i've got a case of Rock oil TRM 20/60 which is especially formulated and highly recommended for the zed's roller bearing crank.

It's been discussed on about every motorcycle newsgroup out there and everyone still has their opinions. I'm still up in the air whether MC oils are any different. Supposedly according to Shell their 15w40 and 10w30 Rotella oil passes all the motorcycle tests making it completely suitable. I run the 15w40 in summer 10w30 in winter. 10w30 may not be advisable, but it's worked fine as I ride all winter down to zero if it's not blizzard out.
I've told my story of GTX many times, changing oil every 2000 miles since new and after 160,000 miles there was so much sludge in the engine last time I went to drain the oil 8 oz of 200wt goo came out and the other 2.5 qt was permently attached inside as a 1/2" thick mess. I know one thing, Castrol did not work in an old worn engine with blowby. Maybe no oil would, but it sure didn't.