Mineral v. Semi-Synthetic

[philipviana]

Hi all, I know this is a topic that has been beaten to death on this forum, but I can't find the answer to this particular question. I did my first oil change recently. I had a bottle of Motorex 15W-50 4T Semi Synthetic at home weeks before my oil change, and when I went into the shop for an unrelated matter before I did my first oil change, I asked them if this was the correct oil. Someone at the shop said no, do not use 15W-50 4T Semi-Synthetic, and convinced me that it was Mineral I had to buy instead.

So, I ended up having in my possession 1 Liter of Mineral and 1 Liter of Semi-Synthetic. Ironically, I hadn't thought to buy the correct amount of oil for either of these choices, and mid-oil change, I realized I needed to use both bottles to get up past 1.7L (the new filter sucked up so much oil that I ended up using exactly 2 liters of oil ). I did a hearty amount of googling for "mix mineral oil with semi-synthetic" and learned that there is no real danger to mixing oils, especially if they are the same type (15W-50 4T) from the same brand (Motorex). So now my rc390 has a 50/50 mix of Mineral and Semi-Synthetic. Weird, I know.

But now I want to cross my t's and dot my i's, since I have a nagging suspicion that the rc390 engine is a little different than the typical motorcycle engine. Is there any danger in my 50/50 mix on the rc390 in particular? I later heard from someone else that i should NOT use mineral oil in the rc390 engine, and that I should protect my engine by doing another oil change as soon as possible and replacing all the oil with Semi-Synthetic. Apparently the Motorex 15W-50 4T Mineral is "only for the break in of the LC4 engine"... myth?

A little annoyed by the situation and looking for some perspective.

Thanks.

 

[rick]

In theory, semi-synthetic is a mix of synthetic and mineral oil so, you're just changing the ratio. However, I've never mixed oils before.

I don't know where the shop was coming from though. Motorex 4T 15W/50 is the specific oil recommended by KTM in the Owner's Manual (P.185) for the RC390. In general though, I run dino oil for break-in and then full or semi synthetic after that.

 

[TennisFreak]

I read the owners manual, saw no mention of mineral oil.

Heck I've never even heard of putting mineral oil in an engine.

I'm still running factory fill but I am only at 250 miles. When I am done with break in I will go immediately to a full synthetic oil.

Maybe Castrol Power Racing RS 4T full synthetic.

 

[zaster]

I have heard of people preferring mineral oil during the break in period.
After that I only used synthetic on all of my bikes.

 

[philipviana]

Is there a danger to running my mix of 50/50 mineral for the next few thousand miles until my next oil change?

 

[zaster]

Is there a danger to running my mix of 50/50 mineral for the next few thousand miles until my next oil change?

Depends, how and where do you ride your bike?

 

[simpletty]

stick to semi synth i use amsoil in everything and never had an issue, race bikes i used fully synth.

 

[philipviana]

Depends, how and where do you ride your bike?

Daily commuter (25mi / day), weekend canyon carver (anywhere between 50 and 300 miles), occasional trackdays.

Trying to pinch pennies a bit so I'd like to be able to stick with my semi-semi-synthetic mix for a good 1,000 mi or so before I swap to typical semi-synth.

Why do people use mineral oil during the break in period only?

 

[zaster]

Daily commuter (25mi / day), weekend canyon carver (anywhere between 50 and 300 miles), occasional trackdays.

Trying to pinch pennies a bit so I'd like to be able to stick with my semi-semi-synthetic mix for a good 1,000 mi or so before I swap to typical semi-synth.

Why do people use mineral oil during the break in period only?

Good read: http://motorcycleextremist.com/Motorcycle-Engine-Break-in-the-Right-Way!.html

 

[Treachery]

Is there a danger to running my mix of 50/50 mineral for the next few thousand miles until my next oil change?

No. So long as you have the correct amount, and "next few thousand" is within the specified interval. For my semi-informed purposes, the exception to this would be if you do multiple trackdays. I'd cut the interval by half if you do that.

Disclosure: I'm neither a motorcycle nor petroleum engineer, and I don't play one on TV.

 

[philipviana]

Good read: http://motorcycleextremist.com/Motorcycle-Engine-Break-in-the-Right-Way!.html

Quite detailed read. I'm at 1250 mi now, so nearly past the 1500+/- he recommends (for the daytona) for mineral oil use. Author seems to suggest that while people typically switch to synthetic after the break in, it's fine to use mineral thereafter.

No. So long as you have the correct amount, and "next few thousand" is within the specified interval. For my semi-informed purposes, the exception to this would be if you do multiple trackdays. I'd cut the interval by half if you do that.

Disclosure: I'm neither a motorcycle nor petroleum engineer, and I don't play one on TV.

What is it about trackdays that demands increased frequency of oil changes? Is the engine just that much more stressed at the track?

 

[Treachery]

Both the engine and the oil are subject to more abuse at the track: Higher sustained RPMs, higher sustained operating temps, more load on the moving parts. That being the case, and given that there's less than two quarts doing the work, I'd probably change after 2-4 trackdays, or 2 trackdays and some degree of street use. Can't hurt anything but your wallet.