well, i hope i didn't curse this thread or anything. nothing since my last post... anyway, i met a local XR guy who was one of the mechanics for the Honda Baja factory team. (when honda bailed on the 600, they just pitched everything into the dumpster. somehow it made its way to a warm garage in north san diego county - grin) anyway, i got pointed in his direction for some replacement rocker arms for my xrr. turns out he is a very nice guy - of course, he rides an XR650R - so i immediately hit him with the question "did honda have issues with the oiling system in the xr's?" he said, well we used to keep a 12mm wrench in our pockets to crack the upper oil feed tube banjo bolt every time one of the race xr's was started... his basic comment was that despite honda's claim that the oil pump was self priming, and really wasn't, and the fact that they installed a check valve in PumpA feed port that didn't check very well, if you didn't crack the line and confirm oil flow to the top end, you had no real guarantee the the pump was moving oil. he also said that most of the oil goes to the top end, despite the restrictions in the pipe and banjo bolts. he also mentioned that it is a good thing to check the entry hole in the case for the main oil gallery. it is the one that the oil filter cover has to line up to. minor misalignment during the case tooling can cause that hole to be _very_ small. other than that, he did not have a lot more to offer on the topic, just crack that line when you start 'er up.
neil in san marcos
Anyone have a collection of RFVC oil pumps?
Started by
HeadTrauma
, Nov 28 2009 05:22 PM
59 replies to this topic
Posted 05 February 2010 - 07:25 AM
That is not too surprising, the top end is where the "plain" bearings would be that require the most lubrication. I would guess that the added oil flow to the head would also aid in cooling.
Posted 10 March 2010 - 11:22 AM
I thought I would add a few more things I have dug up in the last month.
-Looking at the oil system diagram in the manual, the oil pump check valve only appears to prevent oil from draining out of the top end and filter, not the frame reservoir. The oil pump check valve plunger also appears to have a low tension coil spring. I have no idea if it is related to oil starvation failures, but I can picture that plunger getting stuck open and causing either a dry top end on startup or getting stuck shut and just starving the top end(and crank!) completely.
-Most of the RS600 part numbers have the same first five digits as the XL600R pump. Even the right crankcase cover and oil pipe numbers are very similar. Unless someone can provide real dimensions or at least photos of the RS600 and other pumps, that makes me doubt that the RS600 actually had something non-standard.
-The HRC instructions for the XR600 Power Up kit say to reverse the positions of the oil orifices that feed the frame reservoir and the op end. Standard, the larger orifice feeds the oil filter, crank, and head. By switching the orifices, it looks like oil flow is reduced to the top end while the scavenge pump is allowed to send more oil to the frame. I think the idea behind that is to ensure that the "pressure" side always has ample supply from the frame res. I guess it might be possible for sustained high-speed to send too much oil into the gearbox and perhaps drain the frame and ultimately starve the top end.
From what I have been able to find, those models' pumps only have a wider scavenge section while the pressure side is the same all the others. That said, it does provide hope for the possibility of using the high-cap scavenge section of an FMX/SLR and replacing the pressure side with the wider scavenge section of a standard pump. The only problem is that it would require machining a new outer housing.
-Looking at the oil system diagram in the manual, the oil pump check valve only appears to prevent oil from draining out of the top end and filter, not the frame reservoir. The oil pump check valve plunger also appears to have a low tension coil spring. I have no idea if it is related to oil starvation failures, but I can picture that plunger getting stuck open and causing either a dry top end on startup or getting stuck shut and just starving the top end(and crank!) completely.
-Most of the RS600 part numbers have the same first five digits as the XL600R pump. Even the right crankcase cover and oil pipe numbers are very similar. Unless someone can provide real dimensions or at least photos of the RS600 and other pumps, that makes me doubt that the RS600 actually had something non-standard.
-The HRC instructions for the XR600 Power Up kit say to reverse the positions of the oil orifices that feed the frame reservoir and the op end. Standard, the larger orifice feeds the oil filter, crank, and head. By switching the orifices, it looks like oil flow is reduced to the top end while the scavenge pump is allowed to send more oil to the frame. I think the idea behind that is to ensure that the "pressure" side always has ample supply from the frame res. I guess it might be possible for sustained high-speed to send too much oil into the gearbox and perhaps drain the frame and ultimately starve the top end.
torchevo said:
Read my post again; the XR650L has the smaller oil pump regardless of year, only NX650 (and its derivatives SLR650/FMX650) has the wider pump.
From what I have been able to find, those models' pumps only have a wider scavenge section while the pressure side is the same all the others. That said, it does provide hope for the possibility of using the high-cap scavenge section of an FMX/SLR and replacing the pressure side with the wider scavenge section of a standard pump. The only problem is that it would require machining a new outer housing.
Posted 10 March 2010 - 07:21 PM
I've got a pump out of an '88+ XR600R if you want me to measure somthing on it.
Posted 10 March 2010 - 08:16 PM
HeadTrauma said:
From what I have been able to find, those models' pumps only have a wider scavenge section while the pressure side is the same all the others. That said, it does provide hope for the possibility of using the high-cap scavenge section of an FMX/SLR and replacing the pressure side with the wider scavenge section of a standard pump. The only problem is that it would require machining a new outer housing.
Kind of like this:
Posted 10 March 2010 - 08:53 PM
Yeah, like that. 
Well, I think the biggest question mark at this point is the width of the rotors. Distance across the tips of the inner rotor would be useful in determining approximate flow.
pablo83 said:
I've got a pump out of an '88+ XR600R if you want me to measure somthing on it.
Well, I think the biggest question mark at this point is the width of the rotors. Distance across the tips of the inner rotor would be useful in determining approximate flow.
Posted 10 March 2010 - 10:14 PM
what about this off the wall idea I have...
take out the stock pump (so there is no restriction) and put a electrical inline external pump? which could also be used when the bike is not running to help cool the motor
...maybe...
take out the stock pump (so there is no restriction) and put a electrical inline external pump? which could also be used when the bike is not running to help cool the motor
...maybe...
Posted 10 March 2010 - 11:34 PM
It may work when everything does, but it would also introduce many more points of failure to a very critical system.
Posted 11 March 2010 - 01:33 AM
-Looking at the oil system diagram in the manual, the oil pump check valve only appears to prevent oil from draining out of the top end and filter, not the frame reservoir. The oil pump check valve plunger also appears to have a low tension coil spring. I have no idea if it is related to oil starvation failures, but I can picture that plunger getting stuck open and causing either a dry top end on startup or getting stuck shut and just starving the top end(and crank!) completely.
there is a low tension spring for the check valve and yes i believe its only there to help keep the top end from draining back. both check valves (i have two pumps) i looked at are rubber tipped so i can easily imagine one getting stuck closed. i am also a little bummed that the scavenge pump rotors on both the pumps i have are showing signs of passing metal while the pressure pump rotors look fine. steve also mentioned that the honda factory mechanics changed oil pumps often...
my current issue is that i feel the scavenge pump pushes a lot of air into the frame as it does its job, but the frame with its small vent doesn't allow the air to escape and pressure builds up. most dry sump tanks vent back to a valve cover as well as having a large vent to the atmosphere. i dunno for certain - my new rocker arms just showed up so i have yet to do any testing to prove my theory.
i do like this thread. hope we can keep on digging up good info.
have a dandy,
neil
there is a low tension spring for the check valve and yes i believe its only there to help keep the top end from draining back. both check valves (i have two pumps) i looked at are rubber tipped so i can easily imagine one getting stuck closed. i am also a little bummed that the scavenge pump rotors on both the pumps i have are showing signs of passing metal while the pressure pump rotors look fine. steve also mentioned that the honda factory mechanics changed oil pumps often...
my current issue is that i feel the scavenge pump pushes a lot of air into the frame as it does its job, but the frame with its small vent doesn't allow the air to escape and pressure builds up. most dry sump tanks vent back to a valve cover as well as having a large vent to the atmosphere. i dunno for certain - my new rocker arms just showed up so i have yet to do any testing to prove my theory.
i do like this thread. hope we can keep on digging up good info.
have a dandy,
neil
Posted 11 March 2010 - 02:09 AM
Not sure if it'll help (I didn't read the whole thread) but I've got a spare '86 oil pump. I'd be happy to measure anything you might need to know, just show me what you need!
Posted 11 March 2010 - 06:16 AM
SoCalXR600Rmonkey said:
- so i immediately hit him with the question "did honda have issues with the oiling system in the xr's?" he said, well we used to keep a 12mm wrench in our pockets to crack the upper oil feed tube banjo bolt every time one of the race xr's was started... his basic comment was that despite honda's claim that the oil pump was self priming, and really wasn't, and the fact that they installed a check valve in PumpA feed port that didn't check very well, if you didn't crack the line and confirm oil flow to the top end, you had no real guarantee the the pump was moving blablabla
neil in san marcos
neil in san marcos
I already figured if it could be possible for the pump to "deprime" itself after standing still for very long, or because off the "check-valve" not sealing well.
Oil can flow out of the frame-tube into the oil pump, into the oilfilter and through the crank to the engine-cases..
But the oil in the cover with the oilfilter is higher then the oilpump (from memory, have to check this), and that would mean the oil pump could never run completely dry.
But if "almost" all oil has ran away, except the last bit in the oilpump and oilfilter, and the frametube is empty it will *perhaps* take a while before oil is pumped back in the frametube by the scavaging pump on startup. Perhaps that is the moment the oil-pump can suck in some air..
This would mean that the check-valve would be very important!! I'm going to raise the preload on mine I think!
Posted 11 March 2010 - 10:23 AM
'88-on XR600R oil pump:
Inner rotor width: .316
Inner rotor dia (tip to tip): 1.170
Outer rotor width: .237
Outer rotor dia: 1.170
Next time I drain the oil in the NX I'll measure that one too.
Inner rotor width: .316
Inner rotor dia (tip to tip): 1.170
Outer rotor width: .237
Outer rotor dia: 1.170
Next time I drain the oil in the NX I'll measure that one too.
Posted 11 March 2010 - 10:54 AM
Thanks! Now we have a baseline for comparison. 
I didn't expect them to be so narrow...
I have been conversing with someone over on ADV and they pointed out something that I overlooked: the crankshaft is lower than the oil filter and the rod bearing is a big point of leakdown that the check valve has no control over. If the engine is stopped with the crankpin at or below the crank centerline, then oil can theoretically drain completely out of the filter housing. In addition, we have speculated that oil from the frame could possibly creep through the pressure pump, up through a leaking check valve, into the filter housing, and then down into the sump through the crank. Another little tidbit is that early oil pumps don't have seals on the shaft. The difference is shown in the photos zrxer posted.
I didn't expect them to be so narrow...
Ilja said:
I already figured if it could be possible for the pump to "deprime" itself after standing still for very long, or because off the "check-valve" not sealing well.
Oil can flow out of the frame-tube into the oil pump, into the oilfilter and through the crank to the engine-cases..
But the oil in the cover with the oilfilter is higher then the oilpump (from memory, have to check this), and that would mean the oil pump could never run completely dry.
But if "almost" all oil has ran away, except the last bit in the oilpump and oilfilter, and the frametube is empty it will *perhaps* take a while before oil is pumped back in the frametube by the scavaging pump on startup. Perhaps that is the moment the oil-pump can suck in some air..
This would mean that the check-valve would be very important!! I'm going to raise the preload on mine I think!
Oil can flow out of the frame-tube into the oil pump, into the oilfilter and through the crank to the engine-cases..
But the oil in the cover with the oilfilter is higher then the oilpump (from memory, have to check this), and that would mean the oil pump could never run completely dry.
But if "almost" all oil has ran away, except the last bit in the oilpump and oilfilter, and the frametube is empty it will *perhaps* take a while before oil is pumped back in the frametube by the scavaging pump on startup. Perhaps that is the moment the oil-pump can suck in some air..
This would mean that the check-valve would be very important!! I'm going to raise the preload on mine I think!
I have been conversing with someone over on ADV and they pointed out something that I overlooked: the crankshaft is lower than the oil filter and the rod bearing is a big point of leakdown that the check valve has no control over. If the engine is stopped with the crankpin at or below the crank centerline, then oil can theoretically drain completely out of the filter housing. In addition, we have speculated that oil from the frame could possibly creep through the pressure pump, up through a leaking check valve, into the filter housing, and then down into the sump through the crank. Another little tidbit is that early oil pumps don't have seals on the shaft. The difference is shown in the photos zrxer posted.
Posted 11 March 2010 - 11:09 AM
HeadTrauma said:
Thanks! Now we have a baseline for comparison.
I didn't expect them to be so narrow...
I have been conversing with someone over on ADV and they pointed out something that I overlooked: the crankshaft is lower than the oil filter and the rod bearing is a big point of leakdown that the check valve has no control over. If the engine is stopped with the crankpin at or below the crank centerline, then oil can theoretically drain completely out of the filter housing. In addition, we have speculated that oil from the frame could possibly creep through the pressure pump, up through a leaking check valve, into the filter housing, and then down into the sump through the crank. Another little tidbit is that early oil pumps don't have seals on the shaft. The difference is shown in the photos zrxer posted.
I didn't expect them to be so narrow...
I have been conversing with someone over on ADV and they pointed out something that I overlooked: the crankshaft is lower than the oil filter and the rod bearing is a big point of leakdown that the check valve has no control over. If the engine is stopped with the crankpin at or below the crank centerline, then oil can theoretically drain completely out of the filter housing. In addition, we have speculated that oil from the frame could possibly creep through the pressure pump, up through a leaking check valve, into the filter housing, and then down into the sump through the crank. Another little tidbit is that early oil pumps don't have seals on the shaft. The difference is shown in the photos zrxer posted.
I always thought that the oil goes past the check-valve, throught the oil-filter and THEN splits to the crank and top-end..
If what you are saying is right, that could be a cause of oil-starvation.
Also what id like to know: Why does the "lubrication side" of the pump need priming, and why doesn't the scaveging side need that?
Because of the check-valve? Maybe that valve locks air in, and the pump can't push the check-valve open with air because air compresses..
Posted 11 March 2010 - 09:00 PM
HeadTrauma said:
I have been conversing with someone over on ADV
I want to thank HeadTrauma for bringing me over here. I'm really interested in understanding what's up with the RFVC oiling system.
One thing I posed on over at ADV was the part numbers for some of the oil pump internal parts (XR600 top end questions thread).
As near as I could tell, all of the big bore dry sump RFVC engines had the same rotor part numbers for both sides of the oil pump. I also discovered that the orifice sizes were the same, 1983-2009.
If you guys find out something different from that, I hope to find out about it.
My theory was the same as posted here. If the frame tank was empty upon start up, then it would be possible to get air trapped in the pump in the short time before the scavenge pump was able to get oil back up the tube and over into the frame tank.
Also, if during a crash the frame tank was level with the ground (or inverted) while the engine was running; could that cause air to get trapped in the pump?
Posted 12 March 2010 - 01:54 AM
Quote
I always thought that the oil goes past the check-valve, throught the oil-filter and THEN splits to the crank and top-end..
yes it does go: pump then filter then filter cover then sidecover where the oil gallery goes north and south. if you remove the banjo bolt on the sidecover you can look down into the oil gallery that heads off to the crank. next time you change your oil filter, take a look at the cover you removed then look at your case. it is this cover to case that steve indicated is not always optimal and can cause low flow.
Quote
, and the pump can't push the check-valve open with air because air compresses..
seems entirely plausible, esp considering the check valve is rubber tipped. i have seen it happen in other devices where a rubber piece would get "stuck". that is why i am thinking that increasing spring pressure is not something i want to do. i am in my motor right now, so maybe i will lock the check valve in the open position and get oil flow to the top end, then let it sit a while and see what happens - like will it move oil.
MY COMMENTS ONLY APPLY TO XR600R as that is wot i got.
neil
Posted 12 March 2010 - 05:58 AM
An oil-starvation theorie:
So in case the check-valve does control the crank-pin and top-end flow(I'll check this tonight):
When the check-valve doesn't seal well the reservoir drains to near emtyness. When you start the engine the pump pumps the last bit of oil away and it sucks in air...after this new oil arrives by the scavegingpump but its already too late. It will take a while before the pump will be primed again, or may not happen at all (because the check-valve locks in air)...
If the oil to the crank isn't controlled by the check-valve this could happen also..
What you could do to prevent the engine starting without oil in front of the pump, and the pump depriming itself, is checking the dipstick to see if there's oil in there before starting. If the dipstick doesn't show oil maybe kick it over without starting until it does? (don't know how long this would take..
)
Have to investigate this further..
If you remove the check-valve it would mean the pressure-pump would function the same way the scaveging side does. (I think)
It should prime itself when the check-valve is removed.. I'm going to test!!
The bad thing is that on startup it could take a while before oil returns in the resevoir before the pump...
Then again, if it primes very quickly without the check valve and the oil is pumped in the reservoir quickly on startup this might actually work.
So in case the check-valve does control the crank-pin and top-end flow(I'll check this tonight):
When the check-valve doesn't seal well the reservoir drains to near emtyness. When you start the engine the pump pumps the last bit of oil away and it sucks in air...after this new oil arrives by the scavegingpump but its already too late. It will take a while before the pump will be primed again, or may not happen at all (because the check-valve locks in air)...
If the oil to the crank isn't controlled by the check-valve this could happen also..
What you could do to prevent the engine starting without oil in front of the pump, and the pump depriming itself, is checking the dipstick to see if there's oil in there before starting. If the dipstick doesn't show oil maybe kick it over without starting until it does? (don't know how long this would take..
) Have to investigate this further..
If you remove the check-valve it would mean the pressure-pump would function the same way the scaveging side does. (I think)
It should prime itself when the check-valve is removed.. I'm going to test!!
The bad thing is that on startup it could take a while before oil returns in the resevoir before the pump...
Then again, if it primes very quickly without the check valve and the oil is pumped in the reservoir quickly on startup this might actually work.
Posted 12 March 2010 - 09:46 AM
I was just figuring: maybe the pressure of the volume of oil in the frametube can press the weak spring of the checkvalve away a little bit, enough to leak oil... Should be easy to test.
Posted 12 March 2010 - 10:44 AM
That was my first suspicion until I checked on a spare engine I have. The spring is not as soft as I thought it would be, but I don't have a good way to test the spring rate, so I can't determine if the weight of oil can actually unseat the check valve.
Posted 23 March 2010 - 08:13 PM
1994 XR650L oil pump:
Inner rotor width: .315
Inner rotor dia (tip to tip): 1.170
Outer rotor width: .237
Outer rotor dia: 1.170
The inner rotor width difference between the XRL and XRR is probably just due to my calipers. I'm guessing the two bike have identicle pumps.
So is there a process for priming the pump?
Inner rotor width: .315
Inner rotor dia (tip to tip): 1.170
Outer rotor width: .237
Outer rotor dia: 1.170
The inner rotor width difference between the XRL and XRR is probably just due to my calipers. I'm guessing the two bike have identicle pumps.
So is there a process for priming the pump?
