Mobil 1 MX4T or AMSOIL Synthetic

[Dom]

Hi everyone.
I while ago I've read CP's article about the best motor oils for the Kat and checked if I could find them up there in the Great White North.
He recommended:
- Mobil 1 Racing Synthetic Oil
or
- Castrol GPS Synthetic Oil.

Well, I can't find the Castrol locally and the Mobil 1 is still called MX4T here.
However while looking around to see what else I could find I stumbled on
the AMSOIL 10W-40 synthetic oil which is even more expensive than the Mobil 1 but seems to meet more standards.

The Mobil 1 MX4T meets API SG, SH/CF and JASO MA.
And the AMSOIL meets API SG, SL/CF, CG-4; JASO MA/MA2; ISO-L-EMA2; API GL-1.

So my question is, which one is the best for the Kat?

Thanks for your answers.

[streebs93]

I run Amsoil...works good for me

[LMT]

They're probably both excellent oils. I just put in Motorex on Wed., full synthetic. Bought from Bike Bandit.

[RossW]

As far as I know MX4T and Racing 4T are basically the same thing. I'd go with the Mobil1 simply because it's cheaper, but either should be fine.

[plupien79]

Both are good choices.
I'm on my second oil change of amsoil. Working good.
Was going to use Mobil but the store was out...

[hardlydangerous]

Around here the Mobil 1 4T is most then the Amsoil MCF10w-40

Personally I have run Amsoil for the past 15+ yerars with outstanding results in my customers and own personal race bikes and play bikes, drag sleds, Atvs cars etc etc.
like I have said many times, I have a lot of customers that race and play hard and have used every oil out there to the extreme including Motoul, Belray and Mobil 1... the guys that switch end up saving a lot of $$ in the long run... the guys that don't.. end up rebuilding 2~3x more often then the other guys...
I mean i can't make people switch but when I have a year old Honda engine in my shop with a blown trans and another with a bad head/valve seals/guides...or a Yamaha with fried cylinder/piston after maybe 20 hours of use on a fresh rebuild

Come on...

Like I always say if you have a half azzed bike use a half azzed oil...
If you have a great bike use a great oil

[IndyGunner]

Amsoil is a TRUE synthetic. Ive heard nothing but great things.

[Daemontrym]

AMSoil is a great product but too expensive for me..

The VFR guys swear by Rotella 5w40 synthetic oil and I have done lots of research on the bob is the oil guy forums. AMS and Rotella seem to be among the favorites. I even use the rotella in my cage too which my upset some of the VW guys we have here.

[The CyberPoet]

...and the Mobil 1 is still called MX4T here.

Same thing, different name. They didn't change formulations

However while looking around to see what else I could find I stumbled on
the AMSOIL 10W-40 synthetic oil which is even more expensive than the Mobil 1 but seems to meet more standards.

There's only one standard that needs to be important to you -- the full JASO-MA (T903) qualification. Any oil that meets that will do the job, and you can ignore all the other letter-combinations on the package.

So my question is, which one is the best for the Kat?

This is like asking which is better -- Baptist or Lutheran. Each has it's dedicated followers, and each is supposedly among best-of-breed for the motorcycle oil market. I doubt you can wrong with either one. The only place that I'm aware that one truly (significantly) outshines the other is in absolute high-temp (overheating conditions) behavior -- the Mobil 1 has a significantly higher vapor temp, but it's the type of thing that's only critical when your engine is already stressed beyond the point that normal oils would have failed.

Cheers,
=-= The CyberPoet

__________________________________________________ ________
CyberPoet's Katana Maintence and Upgrade Parts Offerings
The Best Metal Steel Aluminum Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[Dom]

Thanks everyone for your answers.

CP, on your webpage you state that we shouldn't use API SJ, SL OR SM oils. But the AMSOIL is SL/CF...
Is SL/CF the same as SL? Does it still matter since it also meets JASO MA?

Thanks once again.

[The CyberPoet]

I thought I updated that; I know I updated the Katana Oil Guide.
The motorcycle oil manufacturers appear to have figured out how to make API SL also be JASO-MA rated, although I'm not sure how (would appear to be contradictory). If you can still find API SF/SG/SH and JASO-MA, those will be better oils for the Kats' particular needs.

Cheers,
=-= The CyberPoet

__________________________________________________ ________
CyberPoet's Katana Maintence and Upgrade Parts Offerings
The Best Metal Steel Aluminum Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[mike10562004]

I can boast for amsoil b/c we sell it at the shop i work at but also never heard anything bad about mobil one