Oil, oil and more oil

Reading in this topic because I have 8500 miles with mostly 10W40 Mobil 1 4T. My OCI has only made it over 1000 miles twice I think because the bike went swimming or got so dirty you figure some if it got into the oil. But the couple times I have left the oil in, I notice the transmission getting notchy. Changing the oil restores smooth shifting and catching an accidental neutral less often. Am I the only one that notices this?

I think that sometimes we put more attention to oil than to the air filter.

Changing oil often whatever the oil shouldn't hurt the engine. So the cheapest oil that you change frequently is better than the best oil that you change every now and then.

Air filter is a much more important part. The fine parts are the one that are grinding the combustion chamber. Since the environment in which a dual purpose bike is usually very different one day from the other, the care of the air filter is much more important.

Specific attention to oil is more important when you're on the track or any competition.

For riding in cold weather say down to 10F with highs temps of 50F would it be better to run a 10w30 or 10w40?

I really appreciate all the sane and respectful discussion that is going on here. Three cheers for all.

One thing that I haven't seen anyone mention is that filters get better after collecting some of the particles into the pores in the filter material. All screens, whether they are paper or metal are made to a tolerance and there will be bigger holes and smaller holes than the average (specification) bell curve middle. When those bigger holes get full of a particle the filter does a progressively better job at filtering until the screen clogs and the pressure to push the substance (oil, water, air) through is too great and either the bypass functions or there is starvation downstream of the filter. That is the reason that I have read or heard as the reasoning for leaving a filter in for more than one oil change. Never heard advocated for leaving it more than 2 cycles of oil though.

I would never do that in a new engine because, as seen in several of the pictures, there are a lot of particles that need to be filtered out during the break-in. After that period, if you were not riding a lot of dirt or dusty conditions, and you were changing oils at regular intervals it seems to me that it would provide even better filtering of even finer particles.

What I don't know is if there is a good bypass system built into this engine or if it is one of those engine designs that filters only a portion of the oil that is being moved through the oil pump. More educated minds will need to wax poetic on that! Brilliant commentary any one....

Jon

Can't believe I be readin da whole thang....

Bike: 2010 WR250X  w/ 3206km.

I picked up a K&N oil filter (KN-140) and some Motul 7100 Ester 10W40 100% synthetic oil.
The manual says not to use "too good of an oil", but I've always used Motul in my motocrosses and couldn't resist.

They say it has "wet clutch anti-slipping technology".

What do you guys think? That oil should be ok in the bike right?

I didn't get to ride very much last summer (learner's permit) but just to update on the Motul 7100 Ester 10W40 100% synthetic oil.....I like it. Engine and clutch both feel good. I'll continue using it.

Well, I did about 3000 miles this summer and just did my yearly oil change...
I used the "same" K&N oil filter (KN-140) and 1.3L of Motul 7100 Ester 10W40 100% synthetic oil again since the bike ran great all summer with this combo.
I figure I'll change the filter every time since they are fairly cheap and I run the full interval.

I've been running the Shell Rotella T6 synthetic with the same K&N filter you're using. The oil looks great every time I check it. I live right at the base of the Pine Nut Mtns and frequently climb 2-3,000 vertical feet with a good load on the bike and no level ground for relief. I'm not running WOT except on tough hill climbs, but I'm not babying the engine/oil.