I wish I studied filters more, but, I haven't. So, I'm just throwing some ideas out there at this moment.

Fluid pumps don't care how much resistance there is to pump against, in one turn of a given occlusive-type pump, X amount of fluid will be pushed out of the pump. So, just because a particular filter is "tighter" (more resistance to flow of the fluid), it doesn't mean the flow is any less...it's just that the pressure between the pump and the filter is higher. The pressure PAST the filter will be the same, regardless of the pressure prior to the filter, assuming the pump can keep up it's constant rpms, and therefore keep a constant flow. This is where over-pressure relief valves come in. IF the pressure pre-filter is too high, these over-pressure relief valves allow some of the fluid to bypass the filter.

My GUESS is that these relief valves are most likely to open at cold startup. Of course, if a filter got so clogged up with dirt, the relief valves could open at all times...resulting in no filtering being done.

So, if Pure 1 has a "tighter" filtering screen than Brand X, as long as Pure 1 doesn't cause the over-pressure relief valve to remain open, Pure 1 will be filtering smaller particles than Brand X.

I better go do some studying on it, so I can know enough to talk further about it.

 

Not sure what an occlusive type pump is but the muffler on our bikes acts as a filter and as we know, improving the muffler means there is more flow. I suspect that increasing the micron rating of a filter will allow each "stroke" of the pump to push more oil through. Even a positive displacement pump like a piston pump is effected by the pressure on the discharge side. I've heard it called scavenging efficiency. Bottom line is that the piston pump can't empty the cylinder all the way if the pressure is high on the outlet so it will re-pump the fluid on the next stroke instead of drawing in 100% new fluid.

Every time that the filter bypass is opened I cringe. Reducing that open time is important but not so important that you allow the filter media to be coarse enough to pass grime. A balancing act for sure.

 

I disagree. Gas and liquids aren't similar due to the relative non-compliance of a fluid. Scavenging efficiency is more of a gas-phenomenon, not so much with liquids. So what if a pressure relief valve opens under cold startup conditions? It doesn't mean dirt is running everywhere through the oil and engine, it just means that for that period of time, a given amount isn't being filtered....as long as it's not filthy to start with, it's not inherently harmful. I'll go with the smaller micron filtering medium every time, unless it has a bad anti-drainback feature...which not all motorcycle filters even have...a good example is the KLX...it doesn't even have an ADB valve.

 

Now that I think about it the claim that better flow may be a mute point.

Thinking about what Blackheart58 said.

If the oil pump is going to flow the same volume of oil with both filters there is no benefit in have more flow. The slight reduction in pressure from the pump to the filter shouldn't have any affect on lubrication at all.

 

did another oil change...few hundred under 11,000 miles on the ol' klx250sf...10w-40 semi-synthetic yamalube...cleaned the stainless steel oil filter in some ligher fluid...some small specs and debris came off...found some scraps of silicone (fallen from when i was cleaning the factory silicone off the valve cover after my valve adjustment)...looks pretty good...back in and 1.4 liters of oil in...

 

somebody's diggin around in old threads hahaha.

 

On my CRF, watched the surface of my cam lobes real close after switching to the stainless filter. Looking for scratching with a jewelers lense during valve checks. Experince has shown this is where increase in wear from dirty or contaminated oil will 1st show. The cam turns 1/2 speed so doesn't build a protective oil; barrier at lower speed.

Anyway. been through several top ends on different crf250 builds and I see no wear change at all from using the stainless. maybe not the most scientific method, but releives my fear of using them. That and honda motors ran screens for many many years on motors that wouldn't die. More recently yamaha used a screen filter on the yz450f, but went back to paper on the next motor re vamp.

The biggest thing with my crf enduro bike is it gets in water, a paper filter will clog and bypass. The bypass is big enough to allow the piston squirter jet to clog, which eventully end up in worn skirt and piston slap. With the stainless water in the oil is usually filterd with the oil and it doesn't goo into bypass. (though I have seen clogged stainless before too)

 

And there is where the rubber meets the road, so to speak. THEORETICALLY, I like the non-stainless filter materials. However, in actual real-world results, there may not be enough difference in performance to be able to observe any difference.

Clean oil that is the correct viscosity and has the HTHS characteristics specified by the manufacturer is good. Anything else isn't as good. I'm still not sure the filter material matters so much, in spite of all I've read regarding the Theoretical advantages of disposable finely-rated filters.

 

i have used them since the first oil change in my klx and in ever other bike i own that can use them, as far as cleaning i use a non cerosive parts wash in a ultrasonic cleaner an then throw them into the dish washer in my shop for 3 runs first with degreaser then dawn then nothing just a cycle and heated dry i run 24 of thiese filters 12 bikes 2 filters each and rotate them i cant say i have seen any diffrence in the wear but with how much i change my oil in the bikes i ride all the time they have paid for themselfs 10 fold

 

oh snaps...i forgot i have an ultrasonic cleaner...urgh...i could have stuck it in there while the oil was draining...oh well..next time!...

(didn't want to start a new thread if there was one already)