Background: I have 12,440 miles on the bike, and 3,925 miles on this oil. I added a magnetic drain plug at the beginning of this oil change interval (OCI). The virgin oil figures are from Blackstone, and the used oil figures are from Butler Labs, so compare between labs with a grain of salt. The previous OCI was with an unknown oil (probably Kawasaki's OEM 10W-40) for approximately 3,000 miles.
Note that this oil was used for an Auto-Rx clean phase. (See Auto-Rx Rocks.) The Auto-Rx stopped the oil usage the bike exhibited, which had forced me to add 12 oz. of oil 2,000 miles into this OCI. After that I decided to try Auto-Rx and rode another 500 miles to make room for 5 oz. of Auto-Rx. There was only 1-2 oz. of oil use in the following 1,400 miles, and all happened immediately after adding the Auto-Rx.
To see where the different elements commonly come from in an engine, see the explanation from Blackstone Labs. (Note that most of the Al on a motorcycle usually comes from the clutch plates, but I haven't confirmed that KLRs have aluminum ones.)
I'm still not real happy about the elemental wear metal counts, even though most are trending in the right direction. Good values are in the single digits to low 10's. I'm hoping that a lot of it is from gunk that the Auto-Rx dissolved and that my next UOA will show a continued strong drop across the board--including the Fe.
The total base number (TBN) of 8 is still quite good--the oil additives that counteract acidic combustion by-products are still present in good quantities. A TBN of one or two would mean the additives are so depleted that acidic etching could start occurring. Most oils like Rotella start out with TBNs around 12.
The oil sheared down from a slightly thick 40-weight to a middling 30-weight, even though I replaced about an eighth of the total volume a little after half-way through the OCI. The oil was sheared mostly by the transmission gears, although some shearing also occurs from high RPMs. This middling 30-weight viscosity is not acceptable to me, as it is dangerously close to the viscosity at which transmission gears can exhibit pitting.
There are three options I could pursue to avoid running low viscosity oil:
- Run a 50-weight oil, thus even when it shears it'll still be an acceptable 40-weight.
- Keep running Rotella T 5W-40, but change it more frequently, like every 1,000 miles.
- Run a conventional 15W-40 HDEO (Delo, Delvac, Rotella, etc.) that has very few viscosity improvers.
Option 1 is OK, but the viscosity improvers that shear tend to turn into grungy deposits throughout the engine. This isn't conducive to a clean, long-running engine. Plus, the 50-weight oils usually only have a 15W or 20W winter rating, meaning they're very, very thick at startup. This puts extra stress on the entire starting system during each cold start, and it significantly drags down your fuel economy until the oil fully warms up.
So, Option 1 isn't that great. What about Option 2? The second option would be fine if I didn't have better things to do with my time than changing the oil every month or so on my bike. In a good year I'll ride between ten and twelve thousand miles, so the number of miles an oil can last is pretty important to me. Another negative with this option is that the Rotella 5W-40 still has some viscosity improvers to shear and gunk up my engine. Lastly, the economics aren't very good. At $13 a gallon from Wal-Mart, plus a $5 filter every third change, I'd use nearly eight gallons a year ($104) and spend $20 on filters, for a total of $124 a year.
The third option is to run a less expensive oil that has few viscosity improvers and change it fairly often. Heavy Duty Engine Oils fall into this category. Rotella 15W-40, for example, is only $7 a gallon from Wal-Mart. If the 15W-40 could last 3,000 miles I'd only be spending $21 on oil, but still $20 on filters, for a total of $41 a year. Much better, and I'm only changing the oil every three months! So here the only drawback is the mildly undesirable 15W rating.
Option 3 looks the most attractive so far, but is there any way to get a better W rating? It turns out there is, but the economics aren't quite as attractive. Red Line's 10W-40 oil uses no viscosity improvers, and it's made almost entirely from Group V oils. These oils are synthesized from plant and animal fatty acids and are the purest, most consistent oil we currently know how to make. (The other oils we've been discussing are primarily Group II+ or III oils, meaning that they're just very refined dead dinosaurs. They contain significantly more non-lubricating junk in them that can turn to varnish and sludge in an engine.) The 10W rating means that Red Line will not be as thick during a cold startup as a 15W or 20W, allowing the oil to reach more places sooner and protect better.
Another advantage Red Line has over the HDEOs for my application is that it contains a big dose of moly in it. Moly comes in several different forms, and you've probably heard that moly will cause a motorcycle clutch to slip. That may be true, but not for all forms of moly. Red Line, in particular, uses a form of moly that doesn't seem to cause problems for very many motorcyclists. The advantage of moly is that it is an excellent anti-wear additive, especially in cold engine or high-RPM situations. Because I live and work very close to the major highways I commute on, my engine doesn't get much of a chance to get up to temp before I need to wind it up to 5,500 RPM to keep pace with the traffic. Having a lot of moly promises to reduce the amount of wear that occurs while the engine is still cold.
Unfortunately, as with most things in life, better costs more. In this case, Red Line is about $7 a quart. The price is offset a little bit by the expectation that the oil can last for 6,000 miles. So, doing the math gives us a total cost of $42 a year for the oil. If we change the filter when we change the oil we drop down to $10 a year for filters, for a total of $52 a year. Not quite as frugal as Option 3, but much less expensive than Option 2.
As a result, I've switched to Red Line 10W-40 now. I'll see how far I can stretch the OCI and whether the promise of a superior Group V base stock and lots of moly comes true.
Stay tuned to see if Red Line can stay strong!