Synthetic oil change??

11 replies to this topic
  • toofast2

Posted April 28, 2008 - 03:01 AM


Using Amsoil synthetic 20/50 in YZ450,how often do you change oil and filter?
Can you go longer (hrs/mths) then regular petroleum based oils?? THX

  • grayracer513

Posted April 28, 2008 - 06:12 AM


It depends on which Amsoil you are using. If the oil you are running is MCV "Synthetic Motorcycle Oil", then yes you can run it longer than oils not manufactured for use in a motorcycle with a shared engine/trans oil supply.

But the reason you can is not the same as in a car, and the length of time you can extend its run it is not as long, either. True fully synthetic oils don't suffer from oxidization, evaporation, or acid buildup as much as petroleum oils do, and in an application where they are run as engine lubricants, they can be run 50-100% longer between changes.

However, the problem in a YZF is the the degradation of viscosity caused by lubing the gears in the transmission. Amsoil and a few others are actually blended for this purpose, and handle it much better. (You may have seen that MCV and MCF are actually labeled as gear oils and carry an API grade of GL-1 along with the grades for engine use). Even so, I change mine out after 3 ride days (dirt bike). On the street, you can run it 3-5000 mi, depending on how you ride.

You can establish whether your oil is holding up well in your bike as you use it by having your used oil tested, either through Amsoil or Blackstone Labs. When you get the results back look at the viscosity at 100 degrees C (212 F). The way I see it on the '06 is that it's barely over a quart. That's not a big enough issue to cause me to worry about changing it too soon.

  • toofast2

Posted April 28, 2008 - 10:18 AM


Thanks Gray,yes I'm using MCV,so you change it out after 3 days riding,how many running hours do you equate 3 days too?,and do most owner's who are using a full synthetic in the YZ450's change it as often as you? THX

  • grayracer513

Posted April 28, 2008 - 10:31 AM


3 ride days for us can be anything from 4-9 hours. Over New Year's this year, I let the oil go for 4 days and then tested it. That trip added up to 10-11 hours on Junior's bike. I use MCF (same oil in 10w-40), and it was still a 40 at the end of that.

A lot of guys who use full synthetics change oil that often. In fact, many of them change oil every ride, because they use a low cost automotive oil that is not durable in transmission applications.

I cannot stress enough that the things that normally bear on the oil change interval question don't apply to a YZF, or to any other motorcycle sharing engine oil with a transmission. Oils like Rotella T Syn are excellent engine oils, but don't cut it as gear lubes because such use destroys the additives that allow them to retain their viscosity when hot. The reason is that the oil was not blended for that market, and the additives that give multi grade gear oils their durability are too expensive to use where they aren't planned to be necessary. Many (not, unfortunately, all) oils made for the purpose do use the tougher polymers and hold up better.


Posted April 30, 2008 - 05:41 AM


I like to change my filter every other oil change also.
I feel, better safe than sorry on maintenance.
I run the Amsoil full synthetic and maybe go 6 hours between changes.

Thanks for the info guys.

  • grayracer513

Posted April 30, 2008 - 06:07 AM


I like to change my filter every other oil change also.
I feel, better safe than sorry on maintenance.

Safer would be to change it each time. You are leaving 18% of your old oil in the engine unless you do, for one thing.

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  • Family Man

Posted April 30, 2008 - 03:28 PM


Check out an SS oil filter. Helps motivate you to change your oil when you dont have to spring for a new $12 filter every oil change.

  • 2001YZF426Rider

Posted April 30, 2008 - 07:11 PM


So gray did i understand you right by saying you can run the MCV 3-5000 miles in your bike if you are riding the street? Or did i misunderstand you and you mean for a car?

  • grayracer513

Posted April 30, 2008 - 09:31 PM


An acquaintance sent me a used oil analysis from a big cube road bike that ran 4500 on MCV, and the oil was OK. Definitely due for a change, but OK.

There is a huge difference between long distance cruising and what happens to a dirt bike.

  • dccd45

Posted May 02, 2008 - 07:20 PM


I throw a new oil filter in my 450 every oil only like an extra 5 to ten bucks

  • Pilfer8

Posted May 02, 2008 - 08:51 PM


I'm still using Yamalube. Change it out every 4-6 hours. It's just something I've gotten used to. At $10.00 CAD per change it's a little pricey though. Is this amsoil any cheaper?

  • grayracer513

Posted May 02, 2008 - 09:43 PM


I don't know what your price would be. I pay an adjusted cost (including shipping) of about $7.80/qt. I buy direct as a preferred customer, which you can also do. Check the retail prices on their web site and figure 35% off that.

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