Wrong oil?!

No, I wouldn't worry about it.

I think you just have to change out that oil earlier than you would for a full synthetic engine oil but that's it I think.

Relax....a crankcase of regular dino oil isn't going to make your engine self destruct. I changed my oil last weekend and there is no crush washer.....instead I found a flat washer that doesn't compress like the standard crush washer.  There would be no need to replace this washer each time you change the oil. You state you have experienced the benefits of synthetic oil vs. conventional. What benefits can you attribute to synthetic vs. conventional in your engine?

To start, my old DR650 ran a bit cooler and smoother with synthetic. I didn't believe it would make that big of a difference in that bike, but it did. As for my most recent car, I switched it to full synthetic when I bought it at 26k miles. I've driven it like I stole it for ten years this month, it has 220k miles now, and it's still as smooth as ever. In my other cars, the engine would vibrate a bit closer to the time where I needed an oil change while running conventional, but I don't have that issue running synthetic. Also, when doing the valve adjustment on a bike or a car, synthetic looks cleaner compared to conventional. I haven't noticed any gas saving benefits between the two contrary to claims made by some companies. So to conclude; less vibration, cooler temp, smoother running, longer engine life. That's my experience thus far. 

This is a very long read about oil, but really spells it all out. It also kills a lot of myths, misconceptions and opinions.

Reading the whole thing changed my choice and procedure on my cars and reinforced what I run in the -10 or any other motorcycles.

Believe and do whatever you like, but I highly recommend reading this first.

540ratblog.wordpress.com

I have been using Shell rotella in all of my cars, trucks, bikes, dirtbikes, lawnmowers for years and years. I buy it in bulk from Walmart when it goes on sale, works out to like $4.75 a quart.

Read up on all of the bike forums, it's damn good oil maybe even among the best oil made. You can buy the synthetic stuff if ya want, but I usually just use the dino oil.

Back in the 70's and early 80's, we used regular old 30 wt car oil in our bikes and I got mega miles on my bikes.

Many race teams have their sponsors brand oil cans, with Shell Rotella in the cans!

Very comprehensive, to say the least. I've read it over and over, taking notes and checking back on different aspects. Five different readers could easily come away with five totally different opinions, which is both predictable and good. The first step is to read it, then go from there.

My first and foremost change is, no more extended miles oil in my cars. It makes perfect sense that, no matter what oil you use, it will all get dirty at the same point and time. The author says typically 5000 miles. Makes more sense than 12-14k miles spec'd out on the extended mile stuff. I also switched brands for my cars based on all of the test results in this study. And, on the cars, I've mostly used 10W-30. Those numbers are dropping down on my future changes. I've been using Mobil 4T racing oil in the -10. The article supports that choice in its overall list. Since the motorcycle clutch shares the same oil, I plan to stick with an oil that's made for motorcycles.

Except for break in oil or really cheap no-name brands, most oils will do an adequate job. Some, of course, much better than others. And the better ones aren't necessarily the most expensive.

Happy to share.

According to the article I linked to in this thread, the majority of the oils listed are fine for non-racing service. The only ones that really looked to be sub-par were the break-in oils. Apparently any name brand oil that each of us has a warm fuzzy feeling about is adequate. One point worth mentioning is the study identified the upper temperature where the lubrcating qualities break down, in some cases dramatically. Our FZ-10s are set to run up to around 230 F where the radiator fan turns on. Some commuters on hot days have reported temps on their FZ-10s hitting 236 F. Matching an oil selection with study results indicating higher temperature tolerance (some rated at 250 F) is also worth considering. 

I'm continuing to use Mobile 1 4T Motorcycle Racing Oil in the bike mainly because it's designated for motorcycles. The clutch shares the same oil with the engine, so this is critical to its operation. Further research I did reinforced the last post regarding the JASO MA designation for motorcycles. This is a friction rating specifically for the clutch. Yamaha calls out for JASO MA which would include MA-1 and MA-2 as acceptable. MB would not qualify, because its dynamic and static friction are not within the range (minimum to maximum) of the MA. So, based on Yamaha's spec the oil must be API SG or higher and JASO MA-1 or MA-2.

The only change in my cars is not running extended miles oil, since I'll be changing the dirty oil every 5k miles from now on. The FZ-10 will be every 4k miles per Yamaha's spec.

Regarding time versus miles, there are other considerations. Low mileage riders, especially those winterizing might want to consider fresh oil at the start of each season. If the low miles are because of short rides, warm up time is reduced which could produce more water from condensation in the oil. Longer rides provide enough heat and running time to evaporate this moisture out of the oil. If annual mileage is below 4000 miles, paying for one oil change per year is a cheap investment.

Which weight  for which purpose?

The manual states 10w-40 or 15w-50.  I've always used 10w-40 in my inline 4 bikes, but doing some digging online, I had seen a post where Yamaha was recommending 15w-50 and specifically said not to run 10w-40 Yamalube.  I'm having trouble discerning what is fact and what is just just what someone heard from someone who heard from someone else........

I had used Mobil 1 Racing 4T and Amsoil in the past, and had just recently switched to Redline to try something different (before I purchased my FZ-10).  With Redline, the bikes have been running quieter and shifting smoother that any of the oils I had tried before.  But Redline does not carry a 15w-50, they have the 10w-40 and a 10w-50.

So now I'm looking at Motul, which they only offer the 15w-50 in the 300V and 5100 series, and there's the whole debate as to whether or not the 300V is ok to use on the street.  I emailed Motul on this and their response was that it is listed as a short drain interval oil because it is used by race teams and in racing applications.  If you are not racing and your motor is not heavily modified, then OCI's 2-2.5K miles would be fine, and every 1k miles if you do use it for racing.

So back to my original question, which weight for what purpose?  I have read that these bikes run on the hot side, is this why 15w-50 is suggested?  I plan to have my ECU flashed by 2WDW, and am fairly certain they lower the temp at which the fans come one, so the bike should run cooler.  I do live in southern Indiana where the summers are pretty hot and humid, but the fall and spring can be fairly cool.  I don't race and have no plans to heavily modify the motor.

Not trying to create another oil debate, just want to know which weight should be used for which circumstance, so I can better chose what oil I put in after the first 600 miles.