I Use a K&P Engineering www.KandPEngineering.com on my 2005 Sportster. It can be taken apart and inspected and reused over and over. I'm not into chrome so I use the S4A, which is annodised Black. It has to many advantages over regular filters to list. Check it out. It will be the last filter you have to buy.

 

Mine idles at over 20psi hot. I'll never go back to a throw away filter again.

 

And you have an 88? Your filter does 10 microns? Has a backflow preventer? Has a 12 lb. bypass? Obviously NOT on that one, which means it has pressure, but very little flow. Harleys are low pressure/high flow engines from all I read.

 

I have the Purepower filter. http://www.gopurepower.com and love it

 

I use the k&p

 

I looked all over the Purepower site to try and find the difference in micron rating but they seem to NOT have included a link to the explanation they were going to give, so I have to assume it's only 22 micron as stated.

 

I'll assume your questions are directed at me......I have a 96ci FXSTC, and an 06 XL1200C. I'm running the Pure Power filter on both bikes. The XL's oil pressure is 12-15psi according to the manual. The FX is 38psi according to the manual. The PP filter is 22 micron absolute filtration. 22 microns are 0.000866 of an inch. When I was running the HD 5 micron I'd see my OP sitting at 6psi at red lights. Not any more. And 5 microns measure 0.000196 of an inch. Call me a skeptic, but I don't swallow for one minute that that filter is doing what they claim it is. Their filter is tested by Beta Ratio, meaning that sure, it will catch X amount of 5 micron particles out af Y amount that were introduced into the test. The HD filter is circulating most of it's oil in bypass mode constantly. You try running all your oil through media that restrictive, and your motor will see only drops of oil. As far as the size of the cooling jets in the TC motor, I haven't seen any myself yet. Maybe someone in here that has can shed some light of just what the diameter of them are. But I'll bet they are far larger than either 5 or 22 microns. Nobody's machining passages in motors that small.

 

I'll be sending off for a UOA here in a few weeks to see the difference between using the harley 5 micron filter and the K&P which is rated at a constant 35 I believe. I did a UOA before installing the K&P so I'll be curious to see if there is any difference after 3000 miles with the new filter.

 

Please post your results.

 

All of this and nobody knows how these parts work ?

The drainback valve is used when the bike is not running to keep the oil filter from draining back in to the crankcase thus helping to avoid dry starts !

The bypass valve is exactly that,a by pass !

If the filter media is too restrictive or becomes so with debris the bypass opens to allow oil to flow at around 8 PSI.

Think of this if you will.

You have a can of beverage on the bench,take one finger with 5lbs pressure and slide it to the left.

Now take the other hand and apply enough pressure to stop the slide to the left,now we have 5 lbs on each side so the can is static,you have now taken the can out of bypass !

Once the inner and outer pressure has equalized in the filter the bypass is closed !