Synthetic Oil Users

I'm looking for some feedback from anyone using a full synthetic oil for their WR. I

own a new 2000 WR400F and I am using Yamahalube 10w50 semi-synthetic. Is anyone using Mobil 1 15w50 full synthetic in the gray bottle? I know Mobil sells a motorcycle version of Mobil 1 but they are in the black bottles and sell for twice the price. A local Yamaha mechanic said using a straight synthetic will burn up the clutch. Any feedback would be appreciated.

Friction modified synthetics are the oils that cause clutch problems. I use a full synthetic Bel Ray EXS 10W50 in my 426 with no problems. Actually, it has improved shifting. Mobil 1 is fine if you don't use the one with friction modifiers added. It will say "energy conserving" on the bottle if it is.

I've ridden about 400 km using Shell Helix Ultra 5W40. No problems so far.

I used Yamalube semi-synthetic for a long time but a few oil changes ago I switched to Mobil 1 automotive fully synthetic 15-50. From what I’ve heard and read (see below article) this product has no friction modifiers and from what I’ve experienced it will not induce any extra clutch slippage. I’ve also inspected my plates after the first two changes and they looked fine to me…

Here’s a tech article about using Mobil 1 in motorcycles:

The Great Oil Debate

I am using Amsoil 10W40 full synthetic motorcycle oil and have had no clutch problems. There are two local MX racers that I know who ride YZ-Fs and they use the same oil. They told me that the one bike has never been apart afer two seasons of racing and play riding and the other was pulled down after a season of hard use (to install a Wiseco 420cc kit),and cams,piston etc.were all showing like new. They told me it all measured out perfectly,with absolutely no apprieciable wear.I kmow these guys pretty well and they aren't full of it,so I believe what they told me is true.I think you would see similiar results with any quality synthetic that is specifically made for motorcycle use.(Amsoil,Motul,Torco etc.)Those are all fairly expensive oils,but you get what you pay for.Most importantly,change your oil often.

To each of you who responded,

First of all, thank you for responding. Your

combined thoughts and information have confirmed what I originally thought. I want to especially thank the responder who sent me the article "The Great Oil Debate". I have changed my oil twice using Yamahalube 10w50, but the $6.00/qt price just kills me when I can purchase the Mobil 1 15w50 for $4.50 and its a full synthetic. Thanks again to all of you.


I know Im late to your question, but I recently switched over to Amsoil 20w50 racing oil, was using Mobil 1 15w50. Just adjusted my valves, and the cams and lifters looked nice and shiny with no visual wear patterns, and no clutch damage.

One thing I did notice about the Amsoil, I didn't stall as much in my last enduro. Probably a mental thing more than mechanical.


I have used Mobil 1 in my WR400 for 2 years. I have also used it in my street bike. No problems.

I used yamalube RS (semi-sinthetic) the firt 3 o 4 months, in this period i change the oil 2 time, after my dealers sugest me that use the Motul 3100 100% synthetic. I am doing this 1 years ago and no problem.

I've been using fully Synthetic Rock Oil with no problems

marty in modesto

I have a '00 WR400 and have used Putoline SYNTEC4+ Fully Synthetic. I have done 2000km without any problems at all. I change the oil every 200km , and the filter every 400km. The only downside is that fully synthetic is expensive , but then so is a knackered engine !

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