HP Oil Pump from Mike's

I haven't any experience with the high out put pump and i had bought one.

When talking to an XS650 bike racer, (who won the period 4 750 race series last year here in us), he tried it in his race bike but went back o the original due to loss of horsepower
 
This has got to be the worlds best XS650 discussion group, It's far and away the best one I have ever been part of. Tons of great info and it's all free.
The pump arrived today. First thing I did was assemble it, and holding the housing in one hand gave the shaft a whirl. Smooth as silk, not what I expected, not at all. Then
I took the feeler gauge and tried to force it between the 4 tips of the inner rotor and the 5 bulges of the outer rotor. Not one had more than 0.0015". There is no binding or rubbing anywhere. It has the appearance of a nicely machined piece of kit. There is at this point no good reason to hesitate so am going to proceed and keep you guys posted if anything strange happens

Hope to catch you before it's installed.
Would you happen to know the rotor width of that thing???
 
Yes, the width of the stock Yamaha rotor is 00.317".
The width for the HP pump is 00.475".
Sorry about the inches, I'm using my old mic.

On another note, you can easily force twice as much oil through any orifice of given size, it shows up as higher pressure at a higher flow rate. Spin on paper filters are designed to filter huge volumes of some high viscosity oils. I do expect an increase in systemic oil pressure due to volume, maybe lose a few horsepower, but not too much. There are so many places for it to go. If the oil galleries become the most restrictive part of the system then the bypass valve is nowhere near a pressure differential that will cause it to open. A typical bypass valve is triggered at around 15psig. Even when cold a reasonably clean filter will never show a pressure drop of more than 1 or 2psig. It is extremely rare for a filter to get dirty enough to force the valve open, I mean what kind of criminal neglects their machine for the number of years and miles to pile that much sludge & shrapnel up that the filters are totally clogged. That is why the old time huge filters like Purolater Per-1 have a blowoff pressure of ~8psig while the new smaller ones like Fram 3614 have a blowoff pressure a little higher at 15psig.
There are different kinds of bearings. Rolling element bearings like the XS650 (and all Harley-Davidsons) use are what make the bikes infinitely rebuildable and has earned the respect that few, if any, other Japanese bikes have. If it wears out, stick in some new bearings and off you go. Then there are plain bearings. Theoretically the shaft never touches the race because it is surfing the crest of a wave of oil it creates while spinning. These are called hydrodynamic bearings and are the kind used in cars and most Japanese bikes. Problem is it has to be spinning to work and requires a high pressure oil supply. Every time you start it is a dry start, the shaft grinding on the race until the oil arrives. In car engines they use bronze or some other self lubricating material as replaceable races to compensate so when wear catches up with them, and it always will, there is something you can do about it.
But in motorcycles there is no bearing insert, the shaft spins directly on the aluminum of the head or crankcase casting. For most Japanese motorcycles there is no word for 'rebuilding' because you can't. This is one reason for the nearly universal disrespect we encounter with this kind of bike. They are throw away bikes.
We also have hydrostatic bearings where the shaft is lifted by oil pressure alone before it turns at all. Result=zero wear but these bearings are big heavy expensive, and only see use in special applications like electric generating stations.
 
Spockwerks;

Quote:
"On another note, you can easily force twice as much oil through any orifice of given size, it shows up as higher pressure at a higher flow rate."

What you're saying is only true, if the orifice was originally designed to allow the 100% extra flowrate. Yamaha designed the oil system (oil galleries/oil orifices) on the XS650 to match up with the stock oil pump flowrate, not a pump that can pump twice the stock flowrate.

There is something called the System Curve, when dealing with pumps, that pump a liquid through a system of piping or orifices. Because an orifice has a fixed amount of resistance to flow, the actual flowrate must follow the System Curve.

The next 2 paragraghs, and Fig 6 picture, are taken from a pump manufacturer's web site. They are talking about running 2 equal pumps in parallel, which is the same as doubling the flow capacity of a single pump. This is a good example of what happens when its assumed that doubling pumping capacity, will double the flowrate. The S curve for the XS650 will be more "steep" than "flat", and therefore I suspect the Mikesxs HP pump may increase flowrate by 15% to 20%, certainly not 100%.

Flat system curves
When the system resistance is relatively flat (not much friction), operating additional pumps in parallel will produce a useful flow increase. Incorrectly, many operators expect that flow will double if two pumps are running in parallel. This cannot happen because, when added together, the combined pump curve intersects the system curve at a higher head due to increased frictional resistance and hence each pump will be operating at a higher head and lower individual flow than when operating alone.

Steep system curves
Refer Fig 6.
When the system curve is steep (mostly friction) this steep increase in friction head as system flow increases, means that each pump will be running at a significantly higher head and the individual pump flows will be much less than in single operation. Overall, the change in flow will be small when additional pumps are switched on.
 

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Now it gets interesting with the interpretation of graphs. It would have been more helpful if you had labled what the X and Y axis represent, and why do you take a small slice out of a more comprehensive graph and say this represents the data when the bulk of the graph appears to tell a different story. To me, and I may be misinterpreting, I don't know, it seems that outside the window flow virtually doubles on the high side and displays significant increase on the low side with both pumps switched on.
I never said nor expected to get the full 50% of extra pump output as pure oil flow, that would ignore mechanical friction of the bigger pump, The increased friction of the oil alone, The circulating friction of oil in the galleries and drillways, the extra drag from windage with more oil splashing around inside the crankcases. I am sure I have skipped a few, but there are advantages as well. With that extra deep oil sump from 650Central I've added about 3/4qt of oil capacity, that alone is a big advantage that replaces the oil lost when electric start was initiated way back when. Racers still covet these old style cases for just that reason, oil capacity. All the extra oil lines, a spin on filter and forthcoming full flow oil cooler all add resistance to oil flow that I believe the stock pump is inadequate to overcome at anything approaching acceptable levels.
On a stock engine I agree, it works fine and if it ain't broke you don't fix it. Add about 5ft of extra plumbing, all of which adds resistance to flow and you are setting yourself up for oil starvation. Where? How the hell do I know? But it is an open invitation to Gremlins. And I need them like I need termites
 
Using H for the y axis and Q for the x axis, is standard labelling used in the industry when discussing pump pressure and flowrate. H stands for head (pressure) and Q stands for flowrate. Anyone that has studied pumps, knows those symbols.

Quote:
"and why do you take a small slice out of a more comprehensive graph and say this represents the data when the bulk of the graph appears to tell a different story. To me, and I may be misinterpreting, I don't know, it seems that outside the window flow virtually doubles on the high side and displays significant increase on the low side with both pumps switched on."

I have no idea what you are talking about. The graph I posted, speaks for itself, as a stand alone graph. Where is this more comprehensive graph?

Quote:
"All the extra oil lines, a spin on filter and forthcoming full flow oil cooler all add resistance to oil flow that I believe the stock pump is inadequate to overcome at anything approaching acceptable levels.

Add about 5ft of extra plumbing, all of which adds resistance to flow and you are setting yourself up for oil starvation."

You're not the first person to do these modifications. Other lads use the stock oil pump, with full flow oil coolers and extra plumbing lines, and they have not reported any problems.

You're suggesting that the stock oil pump cannot overcome the resistance, that an oil cooler, filter and extra lines will cause. This shows that your knowledge of pumps and pumping systems is quite weak. The stock oil pump is a positive displacement oil pump, which means it will pump an almost constant flowrate regardless of any down stream equipment that is added to the system.

By far the most restrictive part of the oil system is the various orifices inside the engine,which is how it should be. By comparison the full flow oil cooler, oil filter, and extra lines have little additional resistance.

I know you want to believe that the stock oil pump flow will drop off, if you add the above mentioned equipment, and lead to starvation and engine destruction, but its just not true.

Mikesxs advertising says "double the volume of the stock oil pump!" That statement is what they call "Marketing". While that might be true if the oil was being pumped into an open tank with no piping/orifice retrictions, its a lie when the oil is being pumped through various restrictive orifices inside the engine.

The bottom line................you paid good money for the "HP" pump, and you will get maybe 15% to 20% more flow, so enjoy it.
 
I will repeat what I've posted in prior threads:
When Yamaha built the 80 RWHP OU race engines in 1976 they used stock oil pumps. These engines had dropped sumps not to add more oil but instead to get it down below the spinning crank. A number of racers also added oil coolers (typically the Triumph Trident units) for mile tracks or very hot climates.
Apparently nobody ever suffered a failed engine due to oil starvation, etc. because everyone continued to use the stock pumps well into the '80s. Both the factory engineers and the Yamaha race department concluded the stock pumps were OK at the highest levels of competition. It seems to me the evidence is that you can save your money and spend it elsewhere.
Hard to believe the stock pump is inadequate for ANY street bike. Of course, poor maintenance, cheap oil, too little oil, clogged oil passages, etc. might cause a failure that someone would ascribe to the stock bits.
 
There are suckers for marketing hype for products that produce zip. The fact the XS racers are turning their engines up to 9500+ RPMs using stock oil pumps with no engine failures is proof that the stock pump is up to the task of supping adequate oil for stock or modified engines.
 
650performance.........................yes it seems Spockwerks doesn't want to listen to historical facts about the durability and capacity of the stock oil pump. He has been sucked in by the clever marketing of Mikesxs. Now that he has paid a lot of money, he is trying to invent reasons that the stock pump is so inferior to his new expensive pump, that it could destroy his engine.

Spockwerks is also unable to keep his stories straight.

In one thread he says "On another note, you can easily force twice as much oil through any orifice of given size, it shows up as higher pressure at a higher flow rate"

In another later thread he says " I never said nor expected to get the full 50% of extra pump output as pure oil flow"
 
650performance.........................yes it seems Spockwerks doesn't want to listen to historical facts about the durability and capacity of the stock oil pump. He has been sucked in by the clever marketing of Mikesxs. Now that he has paid a lot of money, he is trying to invent reasons that the stock pump is so inferior to his new expensive pump, that it could destroy his engine.

Spockwerks is also unable to keep his stories straight.

In one thread he says "On another note, you can easily force twice as much oil through any orifice of given size, it shows up as higher pressure at a higher flow rate"

In another later thread he says " I never said nor expected to get the full 50% of extra pump output as pure oil flow"
Yet you have confirmed both statements as relevant and factual.
Cual es su problema?
With one hand you smear the meaning of my words, with the other hand you agree with what I say.
I suppose we are not talking the same language, Retired Gentleman, but that is OK. I joined this seminar to gain a bit of knowledge, hopefully share a bit of my own, get variant ideas, discover new alternatives, and learn some other cool shit along the way. You see, I am enjoying my retirement in contrast to some other people who derive frustration from leisure time. An unscheduled day is my version of nirvana.
Thank you for your enlightening dissertation on fluid dynamics, it suitably raised the bar a few notches from a technical standpoint bringing the discussion up closer to my expectations. You are the keeper of some specialized and valuable information. Pity that I had to piss you off stem to stern in order to get any out of you.
Maybe it just goes that way.
And Jack, you've got me wrong. I am keenly interested in our machines, the developmental process that forged them into the precious icons they are to us all today. Just because I haven't the time to spend answering each and every submission on the subject is no indicator of a lack of interest. Please remember I'm in the middle of a major build here, I would like to do some riding this season as well. Historically, one recurring principal that does seem to over represent itself is that 'Good enough is best'. It has a sibling, the belief that everybody does it this way so it must be right. And a close cousin is, 'We have always (or never) done it this way'.
Mediocrity does have the advantage of very low risk factor.
 
The XS is a very simple engine in design and when it comes to wrenching and over numerous decades of racing,street building,the stock oil pump has held up it's job of supplying oil where it's needed,that's the point everyone is stressing. The " good enough is best" is just that,don't over think it. Slap the stock pump back on and use Mike's pump as a paper weight before the riding season is over.
 
The XS is a very simple engine in design and when it comes to wrenching and over numerous decades of racing,street building,the stock oil pump has held up it's job of supplying oil where it's needed,that's the point everyone is stressing. The " good enough is best" is just that,don't over think it. Slap the stock pump back on and use Mike's pump as a paper weight before the riding season is over.

Heh, Heh. I have 2 original equipment pumps in pristine condition as spares in case it comes to that. Thanks for your input.:bike:
 
I've read this thread with great interest and a smile to myself. I was also tempted at one time to get one of the hi output oil pumps for one of the other 4 xs650's I've restored over the last 15 years. but I didn't and I've not had a single oil related problem in the 15,000+ miles I've put on all of the bikes here in Arizona. i decided to just keep the original stock oil pumps after I performed my own non scientific "oil pump performance" test on each engine. pretty simple, actually. just let the warmed up engine idle, remove one of the valve tappet covers and if i get sprayed in my face with copious amounts of hot 20w-50 engine oil it seems the oil pump is working very correctly. non scientific but apparently accurate considering the number of miles I've put on the bikes over all those hot, hot miles. of course, your mileage may vary...
 
Spockwerks;

Quote:
"On another note, you can easily force twice as much oil through any orifice of given size, it shows up as higher pressure at a higher flow rate."

What you're saying is only true, if the orifice was originally designed to allow the 100% extra flowrate. Yamaha designed the oil system (oil galleries/oil orifices) on the XS650 to match up with the stock oil pump flowrate, not a pump that can pump twice the stock flowrate.

There is something called the System Curve, when dealing with pumps, that pump a liquid through a system of piping or orifices. Because an orifice has a fixed amount of resistance to flow, the actual flowrate must follow the System Curve.

The next 2 paragraghs, and Fig 6 picture, are taken from a pump manufacturer's web site. They are talking about running 2 equal pumps in parallel, which is the same as doubling the flow capacity of a single pump. This is a good example of what happens when its assumed that doubling pumping capacity, will double the flowrate. The S curve for the XS650 will be more "steep" than "flat", and therefore I suspect the Mikesxs HP pump may increase flowrate by 15% to 20%, certainly not 100%.

Flat system curves
When the system resistance is relatively flat (not much friction), operating additional pumps in parallel will produce a useful flow increase. Incorrectly, many operators expect that flow will double if two pumps are running in parallel. This cannot happen because, when added together, the combined pump curve intersects the system curve at a higher head due to increased frictional resistance and hence each pump will be operating at a higher head and lower individual flow than when operating alone.

Steep system curves
Refer Fig 6.
When the system curve is steep (mostly friction) this steep increase in friction head as system flow increases, means that each pump will be running at a significantly higher head and the individual pump flows will be much less than in single operation. Overall, the change in flow will be small when additional pumps are switched on.

Retiredgentleman,
I believe you are comparing apples vs. oranges here. Your curves and argument is based on CENTRIFUGAL pumps, where any engine oil pump I have ever seen is a displacement pump. This means it moves a certain amount of liquid for every revolution. So oil flow is proportinal to pump displacement and pump (engine) rpm. The internal leakage in the pump is depending on system pressure, clearances and oil viscosity, and will have some minor influence on actual flow. So for all practical purposes, the pump displacement and rpm determines the flow, and the unregulated pressure will be according to flow and the flow resistance of the system. With all things being equal, doubling the flow will increase pressure by 41%. This is what Bernoullis law states. So a pump with larger displacement will give more flow AND higher pressure, unless the pressure relief opens. In that case, pressure, and thus flow, is limited by the pressure relief.
 
Dr. John got more power out of an old Moto Guzzi than anyone thought possible. One trick that gave 5hp was 5w-30 Mobile One. The thinner oil gave so much less friction going through the engine than the typical heavy oils commonly used in racing bikes of the era.

You could use a lighter oil with your big pump. More oil volume through the engine with no loss of pressure. The head should run cooler too due to the extra oil volume pulling more heat.

Just a thought.

Tom
 
Dr. John got more power out of an old Moto Guzzi than anyone thought possible. One trick that gave 5hp was 5w-30 Mobile One. The thinner oil gave so much less friction going through the engine than the typical heavy oils commonly used in racing bikes of the era.

You could use a lighter oil with your big pump. More oil volume through the engine with no loss of pressure. The head should run cooler too due to the extra oil volume pulling more heat.

Just a thought.

Tom
Hmmm...Lots of food for thinking. I had figured that was the rational over at Ford when they specified 5w-20 oil for their 4.6L V8 as used in Mustang. I'm lost for words here but turning in the forward direction power transfer from engine to transmission is very efficient, almost clutchlike. But letting up on the gas is like down-shifting without re-engaging the clutch. You can feel the engine brake but just barely. Another rabbit from the MPG hat of tricks
So maybe I really DID see 5 quart bottles of 5w-30 Rotella on the diesel oil shelf at Wal-Mart?! Would that kind of oil be appropriate for our engines? As break in oil, to help the rings get seated it sounds like a winner. Back when synthetic oils were new and mysterious it was common practice to avoid synthetics altogether for the first 500~1,000mi to give the rings a chance to get seated. I am not saying it was right or wrong. I am wondering out loud what current thinking is on subject of break in oils.
 
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