#ygrps-yiv-1271291255 p {margin:0;}I've heard anecdotal evidence both ways. I've heard of people that run nothing but wal-mart oil changed every 5,000 miles and those who run uber-synth changed every 1,000. They'll both tell you they've had very few problems, if any.
Part of my problem is that I paid attention a little too closely in science class, and I see nearly everything in the view of "The Scientific Method" - much to the chagrin of my wife, my pastor and various other people who like to try to convince me of things. What this practically means is that I'm skeptical of any claim unless it is backed up with hard, repeatable data, and that usually means numbers. As Heinlein puts it: "If it cannot be expressed in figures it is not science, it is opinion."
I'm also of the opinion that while our beloved "Dirt Ninja" may have a couple of design flaws, the engineers that designed her probably knew what they were doing when they spec'd a 40-weight oil. There's a lot of math, physics and material engineering that goes into engine design and you can bet your dollars against donuts that there was a very good reason behind the selection of that 40-weight oil. I am loathe to go against them without a very sound reason (with data), especially in the realm of the internal workings of an engine that they designed and I just maintain and use.
Now with that having been said, I've been wrong before. We all have. I'm willing to adjust my view based upon new data should it come along. This is another Scientific Method principle that I old dearly as well. My opinion is based upon the best data I have available to me right now. I'm not emotionally tied to my opinion, and I actually hope to always keep an open mind to new discoveries.
-Jeff Khoury
[b]From: [/b]"kconcour1"
[b]To: [/b]"DSN KLR650" DSN_KLR650@yahoogroups.com>
[b]Sent: [/b]Wednesday, January 19, 2011 11:09:48 AM
[b]Subject: [/b][DSN_KLR650] Re: Cold Weather starting
All the math sounds very logical and well researched. Unfortunately logic is a way to go wrong with confidence. Whether that is the case here I couldn't say.
While I only have anecdotal evidence in 4 bikes 2x ~175k miles in one motor on a Concours a 2001 and 1994) and 45k miles in a 1999 KLR bought used with 12k and a bought new 2008 KLR with 46k miles currently on the clock.
All of the above motorcycles are still on the road (I no longer own any but the 2008 except the 1994 Concours with 275k miles which I killed in a tank slapper on I-95 still went 750 miles to get me home but not worth fixing). None of them exhibit any unusual signs of wear. All I used in them after the first change in was synthetic oil 20-50 every 6k miles until all I could get was 15-50(currently run NAPA brand synthetic 15-50). As soon as I put 5-50 (all I could find when I needed it) in the 2008 KLR this summer it went from using 1 quart per 3k miles to 1 quart in 500 miles (prompting a change @ 4k).
I did kill the original engine in the 1994 Concours. It dumped all the water out on I-270 going around DC but that is another story on temp sensor placement and 20 degree temps. Well that and having to get to work 180 miles down the road the next morning which it did. Just replaced the engine with a used one never even opened the old one probably could have saved it but wasn't worth the time.
In short all my experience with heavier oils runs contrary to what you are saying. Whether this is from the way I ride or some other factor I couldn't say. But all cranked/started right up down to 6 degree temps. It "may" make a difference if the battery is already going down hill but that is the only way it will really make a difference IMO.
Mike Nasca
Just so you know haven't owned a car since 1984. So the only way I was getting to work was on the bike or bicycle. Even if there was 6 inches of snow on the ground. Can be done but better have crash bars on the Concours because you will be falling over, every now and again.
--- In DSN_KLR650%40yahoogroups.com, Jeff Khoury wrote:
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> I used to think so as well, then I did some in-depth research into the science-y stuff about lubrication in engines.
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> I've posted the link many times, so I'll spare you all another round. But essentially it boils down to this:
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> Most engines are designed to run with an oil viscosity of around 10-15cS. At cold temps (engine-wise, meaning under 150F), 20W oil is way thicker than that, it won't pump very well and it fails to properly lubricate your engine. Your oil pressure is too high, flow is too low and this leads to the common consensus amongst engineers that 90% of engine wear is happening at startup.
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> Now, when they're at normal operating temperature, a 40 and a 50 do not vary between them that much. A 40 (second number) will be 12.5-16.2cS and a 50 will be 16.3-21.8cS. That's not that big of a difference, however the 50 is outside the normal design range of your engine.
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> However, at startup the difference is dramatic: Your 20W-50 at 75F will measure something about 200, and 5W-40 will measure about 70. 70 is still way too thick, but it's a heck of a lot closer to 10 than 200 is. When the temp is 40F, 20W-50 is too thick to even measure, yet a good synth 5w-40 still flows pretty well.
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> So, in summation: 20W-50 is too thick even at operating temp, but not too terribly. At startup, it is atrocious. On a cold morning it is beyond atrocious.
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> I have an '09 and I run Rotella T6 5W-40. It consumes very little oil unless I'm flogging it at 80MPH+ for long periods. I've also noticed that the consumption may not be coming from seepage past the rings as I initially thought, but rather being sucked up through the pcv tube into the airbox. After a particularly fast stretch of I-5, I stopped for gas and noticed a big pool of oil on the ground. I nearly had a heart attack until I noticed it was coming from the airbox drain. A side effect of the PCV valve mod is that any oil that gets sucked into the airbox cannot run back down into the crankcase when the engine slows down, but then just accumulates until it runs out the airbox drain.
>
>
>
> -Jeff Khoury
Stu
PS Where is John Lyon these days?
--- In DSN_KLR650%40yahoogroups.com, "guymanbro" wrote:
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> Still up for grabs as far as I know...
>
> Is it true, Stu?
>
> da Vermonster
>
> --- In DSN_KLR650%40yahoogroups.com, "Fred Hink" wrote:
> >
> > Did anyone ever win Ben Stu s Money ? (search the archives)
> >
> > Fred
> > 