Question regarding 2 bikes and AZ Phoenix heat

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Jan 16, 2021
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I live in the middle between Tuscon and Phoenix and I ride year round atleast a couple times each week.
Either to go get some coffee, explore, or to commute to work.
It gets to be 115-118 out here during the summer and just warm the test of the time.

Bike 1: 2022 Triumph Street Scrambler sandstorm edition 900CC parallel twin
Triumph specs both 10w40 and 15w50 for this bike which is liquid cooled. Do you think 10w40 is fine or should I go for the 15w50?
I am not sure whats in it because the dealer serviced it before I bought it. The bike only had 941 miles when I bought it from there used
on sale. Funny ironic part about is, 2 days after I traded my 17 Hayabusa in for it, I won a gallon of Motul X300 10w40 in a raffle at Cycle Gear.

Bike2: 2001 Honda Valkyrie
I bought this bike for touring and long rides with my son. It is also a project for my Dad and I too since he always wanted one.
I am currently running a fresh change of Mobil 1 4T Racing 10W40 synthetic. This bike is liquid cooled and has a much larger
cooling system/Fan setup than the triumph. Should I stay with the 10w40, or consider something a little heavier?
 
I'd say the 10W-40 is just fine for both. "If" I am remembering correctly, the Motul X300 10W-40 used to have nearly identical specs to the M1 motorcycle oil, I see the numbers between the two have drifted a little bit, but the formula for a successful 10W-40 motorcycle oil is pretty clear. The M1 is a superb oil and pretty much as good as it gets.

Both bikes being liquid cooled, will have reasonable oil temps, which is what matters. Do either have a way to display oil temp? Of course, you could always use a thermocouple and dip it into the oil during a ride, or configure a real oil temp gauge.

Motul has a superb HTHS of 4.3. The Racing 4t
M1 10W-40 motorcycle oil is said to have an HTHS well over 4 (some say as high as 4.5, I seem to recall 4.15) but I don't have conformation on that.
M1 15W-50 oil, one of my fav's, also has an HTHS of 4.5
M1 20W-50 V-Twin, one of the most robust oils ever made, has an HTHS over 6.0.
 
The ultimate question - what is your oil temp?

With a liquid cooled bike, it will be a lot less susceptible to variations in air temperature.

Unless the manufacturers specify something different in the case of extreme heat, I think you’re good with that oil in either bike.

That said, if the Valkyrie has the better cooling, use the 10W40 in that, on the assumption that its oil temperature will be more stable. A guess, of course, but not an unreasonable one.

Since the Triumph allows either 10W40 or 15W50, you could wait and run a 15W50 in that, as a hedge against potentially high oil temps in the summer. Another guess, but not an unreasonable one.

My daughter lives in Cave Creek by the way - I know what kind of heat you’re talking about - stay cool!
 
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I saw the reference above to Cave Creek and thought of this funny video:

I don't know of any oil that can handle the temps that day at Cave Creek :ROFLMAO:




Back on topic, does either bike have well known items that tend to wear rapidly? Cam lobe or follower issues? If so, the higher viscosity oil would be worth trying to prevent unnecessary contact. If not, it is quite unlikely that liquid cooled engines will experience 'air-cooled' engine oil temps that necessitate the higher viscosity.
 
Do you think 10w40 is fine or should I go for the 15w50?
Should I stay with the 10w40, or consider something a little heavier?

According to the riders with 100,000 miles on the clocks either
viscosity will meet and exceed your mileage expectations... what
you might notice running the freer flowing 40 grade are lower coolant
temps because of the oil drag of the 50 grade...

Technically speaking oils are only graded on flow in cSt (centi stokes) and
they are not graded on thickness in inches nor weight in ounces...

The measurable difference between a 40 and 50 grade is the amount of flow powered by gravity...

FlowTest40v50.webp
 
I live in the middle between Tuscon and Phoenix and I ride year round atleast a couple times each week.
Either to go get some coffee, explore, or to commute to work.
It gets to be 115-118 out here during the summer and just warm the test of the time.

Bike 1: 2022 Triumph Street Scrambler sandstorm edition 900CC parallel twin
Triumph specs both 10w40 and 15w50 for this bike which is liquid cooled. Do you think 10w40 is fine or should I go for the 15w50?
I am not sure whats in it because the dealer serviced it before I bought it. The bike only had 941 miles when I bought it from there used
on sale. Funny ironic part about is, 2 days after I traded my 17 Hayabusa in for it, I won a gallon of Motul X300 10w40 in a raffle at Cycle Gear.

Bike2: 2001 Honda Valkyrie
I bought this bike for touring and long rides with my son. It is also a project for my Dad and I too since he always wanted one.
I am currently running a fresh change of Mobil 1 4T Racing 10W40 synthetic. This bike is liquid cooled and has a much larger
cooling system/Fan setup than the triumph. Should I stay with the 10w40, or consider something a little heavier?
15/50 for both no way would I use anything less than that. 10/40 would be fine for riding in temperatures up to 80° and sporadically higher.

Water temperature and cooling system capacity has nothing to do with oil temperature. If you want to know the temperature of your oil you have to measure it and you might be quite surprised.

Clearly, riding a bike in the most extreme of temperatures in the country would clearly call for a 50 weight oil, which, according to the literature is allowed by the manufacturer.
It’s just common sense
IMG_9763.webp
 
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The ultimate question - what is your oil temp?

This is the only thing that matters and what the manufacturer recommends.
In this case, being the he rides in one of the warmest places in the country, I would choose the 50 weight oil as allowed by Triumph. I would choose that for any bike that routinely rides in temperatures above 80°.

Water cooling system and capacity does not correlate into oil temperature. Many bikes oil is actually sprayed on the bottom of the pistons to cool the pistons from overheating.
 
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My VFR800 Sport Touring customers...
That's awesome
I just sold my 95 VFR750 last may that I owned since 2008. It was a great bike I just wish that I could find fairings for it. My side fairings and tail started to break apart at all the mounting points. So I just took them off and rode like that for a long time.

I have owned a Katana 750, VFR750, R6, Rocket 3, trophy, FZ6, hayabusa, scrambler, and now the valkyrie. I have to say out of all of them the valkyrie, vfr, and scrambler have to be my favorites. The bonneville is such a nice riding bike along with the valkyrie.
 
I live in the middle between Tuscon and Phoenix and I ride year round atleast a couple times each week.
Either to go get some coffee, explore, or to commute to work.
It gets to be 115-118 out here during the summer and just warm the test of the time.

I commuted year-round for years into the Phoenix metro on a Honda NC700X, as well as riding it all over the West. Red Line 10W30 performs brilliantly in the NCX, which specs 10W30 but the service manual also allows 10W40.

Your use of going to get coffee does NOT require nor indicate the optional 15W50, IMO. If your commute is up (or down) I-10 at full speed, then maybe so. Oil temp is significantly controlled by engine speed, as well as load. It's not influenced so much by ambient temp as by those things, especially on a liquid-cooled engine.

Assuming you do not have an oil temp gauge, and don't care to rig one up or use an IR gun for a period of time, the thing to choose on is what your use is. I've given my 2 cents on that.
(-:
 
In our sportbikes, all high-powered and liquid cooled. I find their shared-sump transmissions work better in 100° F+ temps, with 15w50 in their sumps. I use Motul 300V 4T. In fact that's the only viscosity I use. It's fine at any cooler temperature I'd care to ride the bikes, Usually not below the 40° F. The tires we use don't like temps below about 45° F.
 
I’m the original owner of my 2001 Valkyrie, I’ve used M1 Motorcycle 10-40 most of the time, but have periodically used Rotella 15-40, living here in Southern California.

I have about 42,500 miles on her, no oil issues at all, no burning of oil either, on my last tank of gas I got 38.5 mpg. I’ve never used a 50 wt oil in her. All stock, all original.

1729737153737.webp
 
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