Most riders use NGK plugs and the higher the number, the colder the rating. A cold plug needs to be used in a hot engine (usually due to high RPM), and a hot plug needs to be used in a cold engine. That is to maintain the ceramic and center electrode temperature close to a certain temperature. The purpose of engine oil is to protect the engine from friction but it can't do that if the oil is evaporating off of the upper cylinder at WOT. The higher the content of synthetic oil in a product, the higher an engine temperature it can withstand without evaporating. The temperature of evaporation is called the flash point temperature. An ester synthetic oil has a flash point of 238 celsius, but a group 1 mineral oil is around 120C. Big difference. Mineral oils can still protect if enough oil is added to the gas but in some high performance engines they aren't up to the task no matter how much you add. So the idea here is the hotter the engine, the more synthetic content a product should have. This gives the most protection. Unfortunately you can't go by the flash point listed for any product because of kerosene added to most products to make them more pourable. Kerosene has a very low flash point. In any engine the jetting can be right on and yet it can still seize because the oil isn't protective enough. If jetting is rich enough to create wash areas of around 20% on the piston top and yet the oil is burning black onto the underside of the piston crown then it needs to be more synthetic. This page rates common oils in relation to NGK plug # (on right side of chart): https://dragonfly75.com/moto/plug2.html
This page lists the % of each oil an engine oil has. Don't go by what the manufacturer says about the product being synthetic. If the product has a group 2 mineral oil in it that has some high carbon #'s (similar to synthetic #'s) then they are allowed to call it synthetic. Goldfire Pro is an example of that exaggeration. Also they often call an oil fully synthetic when it isn't. For example Motul 710 is only 2/3 synthetic but is claimed to be 100% synthetic. https://dragonfly75.com/moto/oil.html
All great information, albeit without any context in relation to this site or our particular bikes. Bit like me and my fellow engineer bud comparing antenna polarization patterns for different ground elevation profiles because I like RHCP and he likes Linear feed horns. Even "100% Fully Synthetic" oils come from dead Dinos.
As for plugs, NGK 8 vs 9 they are both on the cooler end of the spectrum, and you can run either one as long as you jet properly for it and your oil mix ratio. Some claim that the 9s will foul more since they are colder, but the heat range isn't about how hot the plug is, the heat rating is about how much heat the plug can dissipate. Spend a lot of time in deep mud and spinning in place in first gear? You'll generate more heat and may benefit from running a 9 over an 8. Spend all your time putting around chasing the grandkids and an 8 may be better suited. But the short answer is the same as for the age old which oil is better...pick one, jet to it, and maintain your bike.
- You can switch between "regular" and "synthetic" without issues
- IIRC Yamalube is made by Spectro, Honda is made by Mobil
- All of the ones listed, with the exception of Repsol, Motorex, Castrol, Putoline, Motul, Silkolene, and ELF are made in the US (if you're in to that sort of thing), and all of them are going to get more expensive along with our fuel under the current global economic situation.
Not trying to be a wet blanket, if you're in to deep diving these sort of things have at it. But keep some perspective on what you're doing with your bike. Oil selection won't overcome inadequate maintenance, and pricier doesn't always mean better. If all you can get is Wal-Mart branded oil, run it, take care of your bike, and have fun. Sure you may not get every last bit of performance out of your 20+ year old bike, but can you really tell the difference between 49 and 50 HP (or for you 200 riders out there 36 or 37...In Arnold's voice "You have weakling bikes" lolol That's a joke, Francis)? I doubt it.
my gripes with your comments
1) my post doesn't relate to your bikes? WTF? You do use 2 stroke engine oil don't you?
2) You then go off on a tangent with a whole paragraph about spark plugs
3) "You can switch between "regular" and "synthetic" without issues". Not true at all. read dragonfly75.com/moto/oilpower.html
4) my post is about the quality of oils, regardless of who is their original maker
5) why would you tell me which oils are made in the USA? Riders know what is available to them in their country.
6) this post of mine is about engine protection, not power
So all this engineering stuff is fascinating. For non-engineers like myself the data is white noise at first. What conclusions I draw from it only come from proper perspective. For instance, the point made about the 9 plug being better than a lower numbered plug in deep mud situations offers clarifying perspective and thus makes sense. However, it would be useful to see data showing the degree of difference between the cylinder temperatures under similar loads verifying and quantifying this theory.
I’m sure some engine designers out there somewhere have appropriated volumes of this data. Until I read that data, I’ll just keep running my Yamalube 2S at 40:1 on non-E 91 octane in my H model 200 with my 8 IDX plug and try to avoid the mud holes.
~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~ Let the good times ROLL!!!!!!!!!!!!!!!! ‘99 KDX 220 / '03 KDX 200 - @%@'18 Trek Slash 8 @%@ ‘22 Rieju MR300 Racing
If you don't ride hard then Yamalube at 40:1 is adequate. Otherwise you need more oil or one with more synthetic than it has. Next time you take it apart take a look at the piston underside to see if any oil has burned onto it. If so then you should consider using a better oil. Check out my analysis of engine oils at www.dragonfly75.com/moto/oils.html
