What's the proper oil operating temp?

I've been reading posts from guys with the temperature dipstick and there have been reports of anywhere from 225-300 degree spreads. What is the optimum oil temp for this or any bike? 300 degrees sounds awfully high to me. I'm going to get one of them for my XRL and want to know what I should be looking for.

I've been running around 200 degrees, but that is on cold days. I've seen it go as high as 250, but I haven't had the bike long, and like I say, the weather hasn't been very warm.

Took a ride Sunday and highest i saw was 225 with air temp maybe 60 degrees, Im glad you started this as i just got my tempstick on friday and have been wanting to know the same thing. Whats the highest your XRL temp should go? Well see what everyone else has to say

Wow, those temps are lower than what I thought, but that's good.

I've been running around 200 degrees, but that is on cold days. I've seen it go as high as 250, but I haven't had the bike long, and like I say, the weather hasn't been very warm.

Thats about where mine runs. In the summer I think I saw it alittle higher once or twice.

I live in AZ. In the winter i see my temp at about 230-250. In the summer months i've seen as much as the 300 mark. XR's only says the 250-300 is optimal operating temp. I think it's to high but my bike just keeps going no matter how hard i push it. My 2 cents

Anywhere under 300F should be OK, any higher and something needs to be adjusted: jetting, fuel grade, install oil cooler, clean mud from cooling fins, etc. Automotive engines have thermostats anywhere between 180-220F degrees so 200 seems about right but maybe a tad cool (and unrealistic) for air-cooled OHVs. Many have said - and I believe - that high engine temps will lead to premature engine wear and failure/rebuild/sale of bike. Basically, the oil gets cooked and loses much of its slippery goodness. Little of this holds true for liquid-cooled engines because the jug is cooled evenly and they usually run very consistent temps. I just got the temp dipsticks from XR's Only delivered last night, hoping mine are running in the 225-250 range but we will see this weekend! My $0.02 and a grain of salt.

230-250 on my dip...

Cool mtns of Az...7K feet elevation.

07 XRL

I average around 250 but have it gets around 300 during long higher speed freeway rides.

Agood reason to run full synthetic oil.

I agree goblin. I've always been a fan of dino oil because I could never get myself to take advantage of the longer change intervals. Not to start an oil debate, but under "normal" conditions and reasonable change intervals, I think the dino is fine. But I also believe the synthetic has an advantage at higher operating temps, so I'll probably go that way this time.

I think I sense another "oil war" starting.:thumbsup:

Automotive engines have thermostats anywhere between 180-220F degrees so 200 seems about right but maybe a tad cool (and unrealistic) for air-cooled OHVs. Many have said - and I believe - that high engine temps will lead to premature engine wear and failure/rebuild/sale of bike. Basically, the oil gets cooked and loses much of its slippery goodness.

Water cooled engines still see oil temps higher than the coolant temp. From what I've read, the oil should be between the boiling temp of water(to evaporate condensation and reduce sludge) and around 300 degrees F to prevent oil breakdown.

Water-cooled engines, like my 650R, can suffer opposite problems from air-cooled engines: oil temps that are too low. My son and I both bought used 650R's and both had thermostats that were stuck open. I have an XRs-Only oil temp dipstick and was noticing only about 165 degrees during a normal ride.

The problem with high oil temp is that most fossil-based oils breakdown above about 320 degrees. Oil gets its slippery lubricating properties due to the long-chain hydrocarbon molecules that make up oil. At high temp these molecules break apart and the oil loses viscosity (gets lighter weight, thinner).

The problem with low operating temps (less than 185) is the opposite: the oil's viscosity is too high (too thick). This alters the properties of the engines bearings, adding internal drag. This internal drag can accelerate engine wear. That's one reason its always a good idea if you can avoid heavy engine loads until your engine reaches normal op temp.

The advantage that synthetic oils have over dino oils is two-fold:

- greater tollerance to high temps. Most syn oils can tolerate up to about 350-365 without molecular breakdown.

- less variation in viscosity over a temperature range, particularly at lower temps. Meaning: the oil is closer to its design viscosity at low temps and this translates to less drag-induced wear during start-ups. Less drag at cold temps also means the engine turns over with less energy (foot or electric).

Does all this mumbo-jumbo mean syn oils are worth the significant price-premium you have to pay? Only you can answer that.

An intersting note: years ago, when Mobil One was first introduced, Mobil garanteed safe engine oil-change intervals of 15,000 miles. 15 thousand. Then they realized they were in fact losing money because you could go forever almost, before you needed to do an oil-change. And so they reduced that interval for most engine types to 5000. Funny.

Obviously off-road, high-dust environments indroduces too much contanimenates to allow such intervals. But on-road, low-dust riding (which is mostly what I do, sorry) allows me to go 3000 miles on all my bikes, using syn (Mobil One). The only exception is if I see the oil temp exceed about 310, then the oil is changed regardless of miles.

My thinking is that if the oil is registering 310 at the dipstick, the odds are the temps are much higher on the cylinder walls and exhaust valve guide(s), and therefore oil breakdown has probably happened. Am I being anal? Probably. Do I care? Nope. My bikes are my babies and I maintain them accordingly.

Ride safe.

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