Fork oil Q...

[8gv]

My mighty KLR250 requires 10W20 fork oil. I have been unable to source that. I am wondering if I should go with 10 or 20. I am 235# (big boned) and load another 50# of crap on the bike.

Is heavier oil better for the heavier load?

[MrPulldown]

typically yes.

Odd that your bike calls for a multi weight oil. Most spec single wieght. My DR350 stock fork calls for 10 weight. But it seems like most newer bikes call for 5 weight, including the rm250 forks I have swapped on there right now.

Yes heavier riders can do a little "tuning" with heavier oils. When was the last time you changed out the oil. Maybe stock freash oil is good enough.

http://www.advrider.com/forums/showthread.php?t=447377

http://klr250.blogspot.com/2011/03/k...and-other.html

??

[8gv]

Thanks for your input. The oil I drained out was like black mud. It's likely more of a time and moisture issue than use as it's an '02 bike with about 6k miles on it.

[MrPulldown]

Sorry I really didn't answer your question.

http://www.motorcycle-superstore.com...WT.MC_ID=10010

Thsi stuff claims that you should use the 10w where it calsl for 10W20. Seems like you should go 20W if you want more dampening. or just go 15 to split the difference.

[SkiFly01]

My sherpa calls for the same oil, I ended up using Motul 20w fork oil. It's good and firm in the Sherpa. Similar fork setup since newcastleadam and I did both my sherpa and his KLR250 fork rebuilds.

[Hipster]

10W20 fork oil? I wounder if that's a type-o in your manual?

Originally Posted by 8gv

My mighty KLR250 requires 10W20 fork oil. I have been unable to source that. I am wondering if I should go with 10 or 20. I am 235# (big boned) and load another 50# of crap on the bike.

Is heavier oil better for the heavier load?

[MrPulldown]

Originally Posted by Hipster

10W20 fork oil? I wounder if that's a type-o in your manual?

i have seen that weight of fork oil referenced elsewhere.

[strongbad]

10w20 is an SAE designation for crankcase motor oil. Trying to apply this crankcase oil designation to a fork oil weight is comparing apples to oranges because 10w20 means that the oil viscosity is 5.6 to 9.3 cSt at 100degC with a HTHS min of 2.6cP. It also passed the two cold temp requirements of the 10w designation. None of which is applicable to fork oil.

The guy who put this chart together seems to understand the problem and took an honest stab at making some apples-to-apples fork oil viscosity comparisons. Look at the viscosity in cSt at 40degC, since that's probably close to the working temp., then look for the highest VI for the viscosity you think you want. VI is a measure of the oil's ability to keep from thinning out as temps increase. Higher is better.

[8gv]

Interesting chart, very technical. I was looking for the column that was titled "proper fork oil weight for Rich's fat ass"

I suppose 20w would be a good start. I bought the bike seven years old with 1400 miles on it. From day one I have had trouble keeping a line on loose surfaces. It's definitely not from an over abundance of power. To do all this work and not try something different seems unwise.

[strongbad]

Actually, if you grok the chart, there is no such thing as 20w for a fork oil and the numbers on the bottle don't necessarily mean anything regarding the actual viscosity of the oil at the temps the oil will likely encounter. The numbers aren't even useful for comparison to other useless numbers on other fork oil bottles.

If you can find your present fork oil on the chart then you have a useful starting point to go thinner or thicker.