Oil change intervals YZ400F

Quick question, I hear about guys changing their oil every other ride, every third, etc... this seems kinda rediculous to me because I ride almost every day when the weather permits. Had 4 strokes all my life and maybe changed the oil once a season or so. I run mobile 1 RT-1040 which is exact API SH rating as yamaha manual says for this bike (full synthetic) and just did an oil change with K&N filter.

So I'm pretty much looking for opinions on how often folks change their oil. Usually I will change mine when it looses it's golden color and starts to turn brown but waaaaay before it goes unclear.

Every 300 miles or so.

Oil filter every other oil change.

Air filter as needed.

Don't lug it/get it hot and don't ride the rev limiter: this has given me good results even with Honda CRF valves.

I can't find any such Mobil 1 product labeled as you have it here, but I suspect it's actually Mobil 1 Racing 4T 10w-40. If so, it's an excellent choice, and actually blended to serve as a transmission lubricant along with being an engine oil. That, more than any other feature of a good motorcycle engine oil, is the most important consideration, because if the oil lacks that ability, as most automotive engine oils do, it won't stay at its full rated viscosity long enough for any of its other strengths to matter.

Using an oil of that caliber, and riding mostly recreationally, I would change it after every third ride day, or between 6-9 hours of actual run time. If you are a little more casual rider, you can go a little longer, but don't stretch it.

Oil darkens for primarily for three reasons:

  • It gets dirty. If the oil turns dark because of debris contamination inside of 10 hours, you have a problem beyond your need to change the oil.
  • It gets hot. Darkening from heat can just be a response to the temperature that doesn't really mean anything, or it can mean that the oil is oxidized. Most REAL synthetics are much more resistant to either of these.
  • It gets contaminated by fuel or by combustion residue ("blow by"). I wouldn't be surprised at this happening in a YZ400 that hasn't been overhauled.

Oil that has sheared out of its full rated viscosity, say from a 10W-40 to a 10W-30, can look clean and new, and there is no way to see the problem visually, since it's only thinner than it should be when it's at full operating temps. It will look normal when drained.

That's the oil I was talking about. The only reason I don't use it is because I can get Amsoil MCF (arguably better, but at the least, equivalent) for $2-3 less/qt.

ya walmart here sells the Mobile 1 for $8.95 and Orielly auto parts will price match them + 10% discount. Still, buying / changing oil once a week is going to get expensive quickly. I'm still kinda stunned that it has to be changed so often. Today was the third ride this week (about 6 hours total riding) and now I need to change my oil? again! Holy smokers!

You can always send a sample to Blackstone Labs (google) at your next change and from that you can determine if you can run it longer safely. You actually ride 6 hours of running time in a day?

2.5 - 4 on average for screwing around. I live near about 500 acres of woodland and have ridden every day so far since I got the carb issue worked out. My RX1 snowmobile has a yamaha 1000cc inline 4 (same motor as the R1 crotch rocket) and the oil change interval is every 500 miles or 3 months. I guess I'm failing to see why it is so frequent on the 400 motor??

up to 40 hours runtime on mobil 1 before oil is no good as in hp loss ph 1-2hp i have done it 3 times of gravel sand and dirt riding believe me if cars do 3000 miles bikes on 10k rpm should do 1500 miles and to all those who havent went beyond 10 hours before an oil change stick your head out of this i got 300 hours now with 20-40 hour oil changes and i haven't even checked a valve

to me i change oil every time i change my car's oil together that way its like changing oil every 3000 miles according to my car even if the bike is still at the 1000 mile mark when the oil starts dragging power

2.5 - 4 on average for screwing around. I live near about 500 acres of woodland and have ridden every day so far since I got the carb issue worked out. My RX1 snowmobile has a yamaha 1000cc inline 4 (same motor as the R1 crotch rocket) and the oil change interval is every 500 miles or 3 months. I guess I'm failing to see why it is so frequent on the 400 motor??
I explained that in post 3. It's the transmission.
up to 40 hours runtime on mobil 1 before oil is no good as in hp loss ph 1-2hp i have done it 3 times of gravel sand and dirt riding believe me if cars do 3000 miles bikes on 10k rpm should do 1500 miles and to all those who havent went beyond 10 hours before an oil change stick your head out of this i got 300 hours now with 20-40 hour oil changes and i haven't even checked a valve
Again, all you have to do is submit a sample to Blackstone or anyone else for a UOA and check the viscosity. I don't really care, since I don't own it.

i might submit my car oil at 3000 and my bikes oil at 1000 using normal 3000mile oil and see how they stack up against eachother my car did 100k miles on oil x at 3000 mile intervals if the oil from the car and the bike are of same quality after 3000 miles from the car and 1000 miles on my bike then changing oil at 100 miles on my bike isnt a bad thing

I run RP (Royal Purple) in my RX1 and my Cobra Mustang. The RX1 doesn't have an internal clutch or transmission so it was acceptable to run the automotive RP in that (I verified with RP) I think at the next interval I'll change over to RP max cycle as I am convinced of their synergy wear properties, I dont mind spending the money now because it can save me big bucks in the long run. I'm not trying to get in an oil debate, we can go round and round and round "to each his own" I know I can go 10K in my cobra with RP but I always change it around 4k. The hard part about the Max Cycle RP is that it has to be ordered, I cant walk into an autozone or walmart and slap a couple quarts down and walk our with them.. The nice part is that if in a pinch you can mix RP with any other oil including non synthetic so if I developed a bad leak out riding I can get back on my buddies yamalube or whatever he carry's in his pack.

motorbike motors don't stay at constant and low RPMs like cars.

going by the book 10 hours before an oil change is good anything less is draining $$$ my final opinion

Going by the book you should change your wrist pin every 15 hours. So much for that.

Any comparison of plain bearing car engines that max out at 7000 or much less to the combined engine/transmission/clutch lubrication chores in a 10,000 RPM ball bearing YZ450F is inoperative on its face. It the classic apples/oranges comparison. In fact, it's more like bananas and watermelon.

Yeah you are right in this comparison so much for newer technology oils that last longer than car engine oils and dont really have a motorcycle age

Yeah you are right in this comparison so much for newer technology oils that last longer than car engine oils and dont really have a motorcycle age
It's a simple matter of the oil being blended for the purpose. Road racing slicks are great on a manicured asphalt track, but not such a good choice in the desert. An R6 is a screaming high tech back road weapon, but a complete dud on an MX track.

Yes, there are any number of extremely high quality, easily available automotive engine oils you could use and leave in place longer IF you had a separated engine oil supply and IF you had more than a quart of it to thrash around. But the beating a dirt bike hands transmission hands out requires gear oil, and the very things that make a good engine oil interfere to an extent with making a good, strong, durable gear oil. The best available products for the purpose rise to the level of API GL1, which is vastly better than any automotive oil is capable of. The trouble is that a dirt bike trans really should have GL5 in it, and so far, nobody's engine oil reaches that.

If you want to cut down your oil changes, the cheap way is to use a straight 40 weight single grade oil. Just be sure you let it warm up really well.

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