synthetic vs conventional oil

6 replies to this topic
  • theyzdude

Posted September 09, 2014 - 02:13 PM


I am getting ready to do an oil change on my 2009 yz450f. I have been running motul 10-40 oil. I was wondering if a synthetic would last longer and lubricate better. And what are some good synthetic oils.

Edited by theyzdude, September 09, 2014 - 04:47 PM.

  • grayracer513

Posted September 10, 2014 - 06:35 AM


It really depends more on the oil additive package the blender used than on the type of base stock the oil is based on.  If it was a street bike that had the engine oil supply separated from the transmission, a synthetic would likely hold up longer.  But that's not the case here, and the beating that the trans dishes out is the single most significant thing the oil in a YZF has to deal with.  If the oil was blended originally as an engine oil, and not as a combination engine and gear oil, it will loose a critical amount of its viscosity in such a short time that none of the advantages of synthetic base stocks has any time to be a factor. 


What you will find, though, is that most of the truly durable motorcycle oils with the upgraded gear oil additives are synthetics, or at least petro/syn blends.  My favorites are Mobil 1 Racing 4T (or V-Twin) and Amsoil MCF Synthetic Motorcycle Oil (or MCV).  Motul also makes a good product.



  • theyzdude

Posted September 10, 2014 - 01:31 PM


So your saying that basically synthetic oil made for combined tranny and engine will last longer and lubricate better than conventional.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted September 10, 2014 - 03:25 PM


Not exactly.  A conventional oil that is actually formulated for use in combined engine/transmission assemblies will outlast a top tier synthetic that isn't. 


The problem currently is that there is no single spec or standard to conform to that can be placed on the label to make the presence of the higher grade, more expensive viscosity improvers known.  The only oil I'm aware of that provides a positive indication on the label is the above mentioned Amsoil MCF/MCV, which shows compliance with API GL1.   Otherwise, you have to go by published lab tests, or the used oil analyses of yourself or others to know.

  • theyzdude

Posted September 10, 2014 - 04:23 PM


So say I buy the amsoil motorcycle oil. Would that be a better oil than the conventional motul oil I have previously been running?

Edited by theyzdude, September 10, 2014 - 04:24 PM.

  • grayracer513

Posted September 11, 2014 - 06:59 AM


Probably.  I don't have any test info on the particular oil you're using, but Amsoil MCF is one of the best you can buy. 

  • theyzdude

Posted September 11, 2014 - 04:26 PM


Thanks for your help.

Related Content


Should I buy this bike? help....... by Numsa Hul

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • * * * * *
  • 10 replies

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.