Oil viscosity

5 replies to this topic
  • YzGuy79

Posted May 02, 2006 - 09:15 PM


I'm already planning on using Amsoil in my bike. But what is everyone here running? 10w-40 or 20w-50? The manual is clear as mud on this subject :crazy:

  • 2fastwhitey

Posted May 02, 2006 - 09:56 PM


Run normal oil if you change it frequently.

I run Chevron or Castrol(anything thats blue j/k) usually whats on sale, but I used to run the expensive stuff like Amsoil. Its a waste of money with regular service. I run 20W-50 most of the time but I'll mix if I'm short, a lil 10W-40 an a lil 20W-50 it won't hurt.

I change the oil filter usually with every change but you can let it go for a ride or two, with a magnetic drain plug and not finding much in the filter. I'll usually do a change every 2-3 rides or 10-14 hrs.

You can do a search and see there have been many posts on the topic, just my 2cents.

  • hitech

Posted May 03, 2006 - 04:14 AM


AMSOIL Motorcycle 10W-40 is recommended. 20W-50 may be used...especially in really hot climates.

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  • grayracer513

Posted May 03, 2006 - 07:35 AM


I use Amsoil MCF 10w-40 except for late May through the end of September when it's a bit hotter. Then I use their MCV 20w-50. I like using the lighter oils because it circulates faster, and volume delivered is more important than the pressure it's delivered at.

What attracted me to the new Amsoil product was a combination of price (Mobil1 MX4T had gone to around $9-10/qt, and MCV costs $6/qt in cases as a preferred customer), and the durability of the oil against viscosity loss in a transmission. MX4T is tough that way, too, but there was the price, and MCF/MCV is actually labeled API GL-1 for use as a gear lube as well as an engine oil.

  • bruntz505

Posted May 04, 2006 - 05:44 PM


Use 20w50.I use it year round.It covers a wider range of temps and pressures.I'd rather have it a little too thick,than too thin.I use Mag1 semi synthetic Motorcycle oil.Costs me about $1.30/qt through work.Awesome oil,ran it in my 250f and showed no wear.Top end was very clean,no deposits or sludge whatsoever.

  • grayracer513

Posted May 05, 2006 - 07:35 AM


Use 20w50.I use it year round.It covers a wider range of temps and pressures.

10w-40 covers from 30 to 114 degrees Fahrenheit, a range of 84 degrees. 20w-50 covers from 40 to 122, or a range of 82 degrees. Ignoring momentarily that the range covered by 20w-50 is actually narrower, what it mostly is is higher at both the upper and lower end. IMO, it becomes a more suitable choice as ambient temperatures reach into the mid 90's, because it is farther from the limit of its range at that point than 10w-40 is. At lower temperatures, there is no actual benefit from using the heavier oil, if the oil used is a good one, and the fact that it circulates more slowly is, again, IMO, a disadvantage.

I have no idea what you mean by your remark concerning pressure.

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