ORK's and Oil Coolers

Oil-Filter Relocation Kits (ORK)  


    Some History




    To ORK or NOT to ORK  


ORKs are convenient! They save time and fuss when changing your oil.

ORKs remove chance of pipe damage, pipe flange/bolt damage, and the cost of new crush gaskets for the front pipe!

ORKs are expensive and you can change oil for probably 5 to 10 years without one to get a pay off on the time savings. Oil changes with the stock filter set up really isn;t all that difficult and once you've done it a couple times, you can do it pretty darn quickly. If oyu change oil 2 to 3 times a season, it's a no brainer. If you change oil once a year you may want to save your money for other stuff.


    ORKs Might Be Somewhat Controversial!!!

There is some "controversy" over the use of ORKs - based on some reported stock cam scoring in cases where ORKs were in use - and also many cases of high mileage bikes that have used ORKs with no failure.


There has been no real research (only anecdotal reports) on ORK use vs. failures.  However, even if the risk of occurrence is fairly low, the severity of the impact / loss can be quite high. Cam scoring and some risk of damaging the head  (because on the inside the cam does not ride on replaceable bearing, but on milled surfaces in the head) so you do risk having to replace the head, plus the cams - and perhaps more if the failure becomes catastrophic.


Here is an excellent summary on the topic - with focus on real measurements, results and the application of larger oil lines for the ORK - 04/14/09 - thanks to Larry M. (A/K/A: Sôphrosynç, Daddo, LMCFL, LarryCFL):

I'm going to give you a readers digest version of the two threads that were running a few weeks ago which apparently you have decided not to read in their entirety. Ditto for the comments that Dave have saved in the Knowledge Base.

A statement in one of the two threads several weeks ago was in error. The gentleman was referring to fluid flow through a conduit (hose) that was open at the end.

At any given fluid flow volume, feeding into an open ended conduit, the fluid volume at the end can remain the same. What this means is that as the conduit constricts, pressure will cause the fluid flow rate at the constriction to simply speed up to the point where the fluid volume remains the same as long as there is sufficient pressure at the beginning of the circuit to push the same volume through the conduit. As the constriction gets smaller, more and more pressure is required to maintain the same fluid volume.

Although the oil delivery system on this engine is technically open ended, the extremely tight bearing surface clearance at the "end (s)" of our conduit make it function almost like a closed system. This is of course necessary because of the fact that any fluid (oil) would of course take the path of least resistance and without fluid pressure build-up, the bearing surfaces with minimal feed requirements would receive almost none of the oil.

We have a constant velocity oil pump on the V-Star 1100. As the engine speed increases, oil flow will also proportionally increase. Oil flow from the pump into the lines will cause a pressure buildup (to a point) when the flow encounters a restriction. Immediately down stream of the oil pump the oil flow is split into two directions by a non-discriminating splitter (or "T"). The portion of that flow that we are concerned with flows past an oil pressure relief valve which at a pressure build-up of 67 to 73lbs. (I do not remember precisely), blows off the excess oil back into the crankcase. Past this relief valve, the oil flows into the stock oil filter chamber, and then up an 8.5 or 9mm gallery to the crankshaft, lower connecting rods and the heads. All of the Remote Oil Filter Kits (ROFK's) interrupt this circuit and direct the flow of oil out of the stock filter chamber and into a series of lines and an external spin on filter, before routing it back to the engine.

Let me head this off at the pass since this question has come up before. The lubrication circuit does NOT filter all of the oil that flows out of the oil pump (edit: "oil pump", not "filter"). It is a Sampling type of filtration system that only filters part of the oil at each pass. Kind of like the filter in a fish tank, it will eventually get to all of the oil (in theory). However, ALL of the oil that lubricates the top end of the engine must flow through the filter. There is no other way for it to get there.

Most of the commonly available ROFK's use 1/8" ID supply lines as a conduit. Under a condition where there was an unlimited amount of pressure, I would suppose that almost any oil, at any viscosity, could be forced through those small lines is sufficient quantities to lubricate the upper engine. But that unlimited pressure does not exist.

When engine oil is hot and up to operating temperature, it is very fluid (almost like water), at 67-73 psi., sufficient oil should flow through even 1/8" ID lines with enough pressure and volume to lubricate the upper engine. That is not, and never was where the problem exists. Stone cold oil will simply not make it's way through the smaller lines in sufficient quantity to lubricate the upper engine at start-up. The oil flow will take the path of least resistance. As pressure builds at the start of the constricted lines, more of the oil will try to flow the other direction at the splitter towards the lower end of the engine and the transmission. Considering this, the remaining available supply will still never increase to more pressure then the relief valve will allow.

My static tests with a cold engine and a set of 1/8"ID oil (brake fluid) lines yielded ZERO pressure at the point of oil re-entry to the engine for close to a minute! Recreating the very same test on the next day, using 3/8" ID tubing and fittings yielded a returning oil pressure reading in the mid 60psi range almost immediately. Think about drinking an ice cream thick shake through a normal sized (1/4" - 5/16") straw, and then switch to a typical 1/8 soda straw and see what happens. . . FAIL!


This link is to a discussion or the merits vs the risks of ORKs - and cams are a player in that discussion.


This is a another thread on the topic, with some new data and opinions - worth the read - relates to a bike engine failure and then opens up to more ORK talk:


  • We would suggest you not install an ORK unless you change your oil more than one time a riding season!  1 hour saved (changing oil) once a year is not worth the cost / damage to pipes risk reduction. In my case I ride 20,000 miles per year and change my oil at least 3-4 times/year.

  • If you want to buy an ORK then buy one with the larger lines

  • If you have an ORK already, buy the larger lines 

         Reasoning: Larger lines have been measured - and they do not cause pressure drop across the filter.

                          Risk is reduced (but not eliminated) - enough so I use a larger lines ORK.


Which Brand  is Best?


There has been a lot of forum discussion on which brand or type is best. As far as I can see, there does not appear to be a clear case to anoint one as the winner.  Some claim the vertical mount type can (will?) be pre-filled to ensure less time the engine is without oil during first stat after an oil change.  Given the internal coating of the lubricated parts, I really am not convinced by this argument. There has been discussion about oil line diameter - also not definitive. I have seen NO reported failures of any ORK - so that is also not definitive.


Net, Net - its whatever floats YOUR boat.


ORK Line Size


There has been a lot of discussion, somewhat heated, regarding the best line size for the ORK.  Most say that the lines shipped with most ORKs are A-OK at 1/8inch ID -  1/4inch OD.  Others say they should all be shipped with larger, 5/16inch ID lines.  Phat offers larger (5/16inch) replacement lines that will fit most ORKs.  See them here.


Here is the "best" argument for getting the larger oil lines (or buying an ORK with larger lines): (In response to a set of comments - included)


"Don't you need to maintain a certain degree of pressure within the oil line? If so won't you decrease the pressure in the line by increasing the size of the hole and thereby reduce the amount of oil you are sending through?"

It doesn't work that way. If there was a constant supply of oil, at the same constant volume coming out of an oil pump, different sized oil lines would all deliver the same amount of oil at the outlet of the line. The larger the line Inside Diameter, the lower the pressure that would be required to deliver that same amount of oil. As the ID of the oil line gets smaller, more and more pressure will be needed to deliver that same amount of oil. As the "hole" gets smaller, more and more pressure will be required to push that volume of oil through the hole.

Here is where we encounter a problem. Some might think that because our 1100 engine has a positive displacement pump, it will continue to build up sufficient pressure to drive the required volume of oil through the small 1/8" ID oil lines. There is unfortunately a major flaw in that argument.

Yes the pump is of the positive displacement type. However, It will not keep building pressure up against that 1/8” hole in the wall.

The reason being, is that the oil discharge from the pump immediately comes to a non-discriminating splitter or “T”. Part of the flow goes directly to the oil filter, and the rest is channeled to lubricate the lower end (primarily the main axle, drive axle, pinion drive and middle drive shaft.). If the oil path to and downstream of the stock filter chamber is either blocked or severely restricted, the bulk of the oil will redirect through the lower end supply up to the point where it will either handle the surplus flow of oil, or the relief valve (between Oil Pump and the Stock Oil Filter chamber) will open. That valve will release oil back into the sump at it’s nominal operating pressure of between 450 - 550 kPa or 64.0 – 78.2psi.

"Also what size are the oil lines on the bike stock?"

The most obvious way to get a handle on that was by direct measurement. I took the opportunity to measure the accessible entry and exit passages that supply oil to the stock oil filter chamber, as well as the passage that delivers filtered oil from the stock chamber to the top end of the engine. the smallest dimension that I measured was almost 9mm (somewhere between 9/16" and 3/8")

Further, if you do a close examination of the engineered drawings of the bikes lubrication passages, it is evident that the supply flows through upper engine galleries that are consistently close to that same size prior to the distribution splits to the various lubrication points.

I'll give you something to think about at this point. After a significant supply of the filtered oil is draw off to lubricate the crankshaft and lower connecting rods, the remaining oil is then routed out of the engine into the two small 1/8" tubes that run up to the heads to lubricate the cams, rockers, and the upper chain gear socket. Now the Yamaha design engineers had determined that each of the heads would require a supply of oil delivered through the very same sized supply line that some of the ORK manufacturers have used to supply ALL of the oil for the top end of the engine.

Do you see something wrong with this picture?




Because of the fact that the fitting holes have been placed so closely together on all of the available Oil Relocation kits, the largest available NPT fittings are of the 1/8" NPT variety.

Now NPT fitting dimensions are a bit misleading as the interior diameter (ID) of a 1/8" NPT pipe nipple is actually somewhere between 1/4" and 17/64". The next available size in NPT fittings would be 1/4". Much too large for the existing fittings to be drilled out and tapped for the larger size. There is just no way to do it with the existing ORK options.

However, when you consider the differences in flow capacity between a 1/8" ID conduit and a 1/4" conduit, the difference is significant. The 1/4" diameter conduit is 326% of the smaller line. because of fluid flow dynamics, the actual capacity is even greater due to a lower frictional drag component in the larger sized fitting. The bottom line is that switching to a larger 1/4" ID conduit is like replacing the 1/8" ID lines on some of these kits with almost 4 complete oil lines of the same size!

The actual resistance calculation for the addition of a remote filter is complicated as the addition of additional "plumbing" of course adds friction to the process.

First we would need to exclude or ignore any friction load induced by the filter itself. The stock filter is just a simple cartridge and we have no flow restriction data for it. But although the replacement filters include a few more internal twists and turns and an anti-drain valve, I’m prepared to count it equal to the stock due to the larger media surface area.

We also need to consider the added friction drag of the galleries in the replacement filter hatch covers and the remote filter mount, not to forget the two short AN compression hoses and 4 - 1/8” matching fittings.

It is because of this additional friction or resistance to the flow of oil, that I have recommended 1/4" ID or 5/16" ID lines. Of course the actual fittings represent a 1/4"+ restriction, but that restriction is only part of the equation when it comes to calculating the oil flow.

Because of the fact that I am also circulating oil through an external oil cooler on my own bike, I have increased my oil line size to a full 3/8" to further reduce the frictional drag component of the entire external system. For a filter alone, I would be comfortable with 1/8" NPT x 1/4" or 1/8" NPT x 5/16" ID fittings and matching line.


Current List of Filters



Oil Cooler for Exposed / ORK Filters

Buck’s Oil Filter Protector/Cooler


Engine Oil Cooler -- Daddo (DaddoCFL)

Depending on the climate where you live, an oil cooler may be something you want to add to your bike as an improvement to your remote oil filter. Sorry folks, but without the benefit of an existing remote oil kit, there is no way for you to add an oil cooler to the engine. An Oil Cooler is added to the circuit by replacing the return line (from the filter to the engine), with a new line that routes the oil path through the cooler, and then returns the cooled oil back to the engine.

Operating your bike within it’s design parameters is one of the best ways to ensure long life for your air cooled, V-Twin engine. One of the best preventative actions that you can take is to make sure that your engine oil is kept fresh and clean, and that it stays within it’s specified operating temperature range.

Every time your engine oil goes through a heat cycle, a portion of its additives can be burned away. When you exceed the maximum operating temperature of your oil, your engine burns off additives at a faster rate and reduces the performance of the oil and its usable life more quickly.

During the summer months, in most areas of the country, making sure that our air-cooled motors stay within their average operating temperature of 210 - 230 degrees can be a challenge. One way to ensure that your engine oil lasts as long as it should is to install an oil cooler. In the summer it is obvious. Riding to places like Sturgis in the summer heat is another given. Ride in the Southern or Southwestern States? Get a cooler. Ride your beast unmercifully? It becomes a good idea. A lot of city driving, particularly rush hour traffic? Put one on.

Are Oil Coolers a required accessory, no they are not. You can adjust your ridding patterns when ambient temperature conditions or traffic congestion is extreme.

After market oil coolers are generally rectangular, but come in a whole range of sizes and configurations. They can be mounted parallel to the ground, or vertically. It really does not care how you mount it as long as it is subject to the air stream when your bike is in motion.

OK, how do you go about choosing an appropriate cooler for your needs? The decision is the same with any other accessory that you choose. Go with whatever “look” tends to spin your propeller.

There are the higher priced billet oil coolers with "highly efficient heat sinks that pulls heat from the oil . . . yadda, yadda, yadda". Then there are the more functional types that are constructed with thin metal, radiator style fins to efficiently dissipate heat into the surrounding air stream.

A “reasonable” individual would understand that the efficiency of an oil cooler is determined by the length of the cooling oil passages encased by finning (is that a word???), the number of fins, the area of finning as a cooling surface, exposure to air, air temperature, motorcycle speed and internal construction of the cooler lines.

An Oil Cooler can be as simple as a “U” shaped, finned automatic transmission cooler, salvaged from a wrecked car, http://www.jpcycles.com/productgroup.aspx?GID=E53F9C44-DA59-4308-855F-576EBEF92EAE&search=oil%20cooler&store=All&page=2 

or as Glitzy as this twin-tube, billet, turned work of art offered by J&P Cycles (and others):


An efficient oil cooler will cool engine oil by around 25 degrees. It will vary with differing conditions

Do you want your oil cooler operating all of the time? The answer is probably not. When you first start the bike, and in very cold riding conditions you really don’t want to chill down your oil temperature. There are three basic ways of addressing this issue. You can install a manual switching valve, you can install an automatic thermostat valve, or you can simply cover the oil cooler element with one of the many leather or synthetic Oil cooler jackets that are on the market. The particular filter that I chose (Lockhart 6000 series) has an internal thermostat and valve to automatically circulate the hot oil through the cooling element, only when the oil temperature starts to creep above 180 degrees and supplementary cooling is required.

Lockhart and others also sell a small external thermostat operated valve which will route the oil through your cooling coil at the appropriate temperature. Or, you can choose a manual switching valve (like the one sold by Jagg) to determine when your cooler will function.

When I started riding, the “high tech” way to restrict the cooling action or a radiator or an oil cooler was to tie a piece of cardboard over the fins to stop air flow. The leather and billet boys have come a long way since then <G>

Do you want to screw up your front fender? Go ahead and bolt an oil cooler (or anything else) to the frame down tubes without first compressing the forks completely to measure how much room you have.

You most likely don’t want to locate an oil cooler to low on the down tubes, and it is absolute idiocy to mount it below the frame. If you hit a curb or some other obstruction, you can dump all your engine oil onto the ground. Unnoticed, this will deep six your engine from lack of lubrication, or worse cause a slippery accident from an oil soaked tire. It is also obvious not to locate the cooler in an area where airflow is obstructed. No airflow equals no cooling.

If you make the decision to upgrade the protection level of your engine, I will be glad to hunt down the parts numbers and sources that you will need for the install. (( DaddoCFL@Earthlink.net )) There is one issue that you will need to come to grips with, no serious manufacturer of after market or OEM replacement Oil handling accessories will use anything less then 3/8” inside diameter tubing on ANY of their products. Because of this you will need to upgrade at least the return line of ANY of the existing Oil Relocation Kits out there (except for Brado’s original kit which of course came with the industry standard 3/8” ID lines). Without 3/8” ID supply and return lines there are NO oil coolers out there that you can connect to. I don’t want to rekindle an old argument, but this is just a simple fact.


More - how to hook it up:


That’s an easy one, as it can easily be accomplished with ANY of the Remote Oil Kits on the market. The plumbing for the unit is supplied by the oil filter module return line. The return line fittings of your ORK are replaced by Chrome 1/8” x 3/8” NPT straight pipe nipple fittings. They are available from J&P Cycles and are relatively cheap. You will also need a couple of feet of 3/8” ID Stainless Braided oil line hose and four Stainless hose clamps.

The unfiltered oil comes out of the engine side ORK module and goes into the Filter side ORK module where it cycles through the spin on filter. It is then routed out of the Filter Side ORK module and into the Oil Cooler Inlet. The cooled oil is then routed to the Engine Side ORK module where it is on it’s way to lubricate the top end of your engine. If you choose an Oil Cooler without an internal thermostat, you will also need to plumb the thermostat into the Oil Cooler’s supply and return lines.