So how was the air pocket introduced? How would you prevent this from happening in the first place? And are there any wear items on the XR650 oil pump that should be replaced (washers, oil seals etc.) while the right side cover is off?
You should at minimum replace all o-rings that seal off the oil passageways. Over time they take a set and reduce their sealing capacity. Also over time the pump components themselves increase their clearances, resulting in loss of efficiency. The loss of efficiency means they can no longer produce as much pressure (fluid squeezes past the tight clearance rotor). Increased clearances also means air can squeeze through the rotor (much easier than a viscous oil), and so when an air pocket is present, the pump cannot generate enough pressure to overcome the spring loaded check valve. This creates a recirculation of the air pocket inside of the pump indefinitely until it is manually purged. A lower force spring can eliminate this problem by allowing the check valve to open at a lower pumping pressure, purging the air pocket. How can an air pocket get into the pump? Three primary causes are: 1) Failure to follow proper oil change procedure 2) Failure to prime the pump after dissembling/reassembling it (manual shows how to pre-fill the pump with oil) 3) A crash in the right orientation that leaves the engine running when the bike is on it's side or slightly inverted can cause the oil in the frame to move to the top of the frame, and the air to the bottom, where it gets sucked into the pump. The pump purges itself of the oil/air mixture until the oil to air ratio is low enough that it's mostly air. At this point the check valve no longer can be overcome, and the engine will continue to run, but without oil to the crank or head. We have a product that give you visual indication of oil flow to the head. Product release is coming very soon: www.spectrummoto.com/product-page/banjo-bolt-oil-sight-glass
Although this is a dry sump engine, there is an amount of oil that is always in the bottom end that gets picked up and sent into the pump. If you do end up draining the oil both from the crank case as well as the frame sump, you should have minimal oil remaining in the bottom end prior to pulling off the side cover.
@@spectrummotollc746 the amount of oil i am removing from this bike feels like i'm closing in on 5 quarts. wondering if the pump was not functioning or cavitating and oil just kept being poured into the resevour. also missing the lower half of the piston oil ring and the running temp prior to the teardown was 250-300 after awhile. might be related?
@@Cyberviper8 Usually if there is air entrapment in the XR650L oil pump (if the rotors are within factory spec) it occurs on the outer rotor side, and it fails to pump oil to the cylinder head and crank. The inner rotor side usually does not suffer from air entrapment because it does not have the check valve, and will continue to pump the oil out of the crankcase up to the frame reservoir. So normally during an air entrapment condition, you end up with a full frame reservoir and a mostly empty engine crankcase and a dry cylinder head. If you have a ton of oil in the crankcase, check the screen on the pickup for the pump located below the clutch basket. It may be clogged with debris that came from the failed piston ring. Also check the pump itself to make sure nothing damaged the rotor clearances to the point of not pumping.
You saved my engine 😂💪🏽thanks for the video
Does the Oil Pump Check Valve Spring go where you removed the cotter pin?
So how was the air pocket introduced? How would you prevent this from happening in the first place? And are there any wear items on the XR650 oil pump that should be replaced (washers, oil seals etc.) while the right side cover is off?
You should at minimum replace all o-rings that seal off the oil passageways. Over time they take a set and reduce their sealing capacity. Also over time the pump components themselves increase their clearances, resulting in loss of efficiency. The loss of efficiency means they can no longer produce as much pressure (fluid squeezes past the tight clearance rotor). Increased clearances also means air can squeeze through the rotor (much easier than a viscous oil), and so when an air pocket is present, the pump cannot generate enough pressure to overcome the spring loaded check valve. This creates a recirculation of the air pocket inside of the pump indefinitely until it is manually purged. A lower force spring can eliminate this problem by allowing the check valve to open at a lower pumping pressure, purging the air pocket.
How can an air pocket get into the pump? Three primary causes are:
1) Failure to follow proper oil change procedure
2) Failure to prime the pump after dissembling/reassembling it (manual shows how to pre-fill the pump with oil)
3) A crash in the right orientation that leaves the engine running when the bike is on it's side or slightly inverted can cause the oil in the frame to move to the top of the frame, and the air to the bottom, where it gets sucked into the pump. The pump purges itself of the oil/air mixture until the oil to air ratio is low enough that it's mostly air. At this point the check valve no longer can be overcome, and the engine will continue to run, but without oil to the crank or head.
We have a product that give you visual indication of oil flow to the head. Product release is coming very soon:
www.spectrummoto.com/product-page/banjo-bolt-oil-sight-glass
Awesome thank you so much for the insight
By any chance have you explored ways to increase oil pressure?
i'm in my first teardown doing research... was there oil in this side case that poured out?
Although this is a dry sump engine, there is an amount of oil that is always in the bottom end that gets picked up and sent into the pump. If you do end up draining the oil both from the crank case as well as the frame sump, you should have minimal oil remaining in the bottom end prior to pulling off the side cover.
@@spectrummotollc746 the amount of oil i am removing from this bike feels like i'm closing in on 5 quarts. wondering if the pump was not functioning or cavitating and oil just kept being poured into the resevour. also missing the lower half of the piston oil ring and the running temp prior to the teardown was 250-300 after awhile. might be related?
@@Cyberviper8 Usually if there is air entrapment in the XR650L oil pump (if the rotors are within factory spec) it occurs on the outer rotor side, and it fails to pump oil to the cylinder head and crank. The inner rotor side usually does not suffer from air entrapment because it does not have the check valve, and will continue to pump the oil out of the crankcase up to the frame reservoir. So normally during an air entrapment condition, you end up with a full frame reservoir and a mostly empty engine crankcase and a dry cylinder head. If you have a ton of oil in the crankcase, check the screen on the pickup for the pump located below the clutch basket. It may be clogged with debris that came from the failed piston ring. Also check the pump itself to make sure nothing damaged the rotor clearances to the point of not pumping.
@@spectrummotollc746it is on my list of inspections for this weekend.