Any tricks on getting that oil screen out of the frame/tank during oil changes? I think a Japanese Sumo wrestler screwed it in.
What size wrench fits it???
Oil Filter Screen
Started by JohnnyG, Jul 09 2001 09:54 PM
6 replies to this topic
Posted 09 July 2001 - 09:54 PM
Any tricks on getting that oil screen out of the frame/tank during oil changes? I think a Japanese Sumo wrestler screwed it in.
What size wrench fits it???
Posted 09 July 2001 - 11:10 AM
a 24mm deep well socket or box end wrench will do the trick for ya. once you get it out (and the puddle of oil with it), you will see that you didn't need to. the screen is so BIG it will only catch chunks that would have already caused the motor to stop for another reason. i'd only open it once or twice a year at most.
Posted 09 July 2001 - 05:53 PM
steve,
ya know, that's exactly what i thought the first time i had the frame screen out-- what the heck is this thing going to catch that won't have already broken the motor? let me say this, if there's something in that screen, look at both sides of the engine for the connecting rod sticking out. my guess is that during r&d stress testing, the oil pump rotors kept losing teeth, and this screen was used to prevent the engine from detonating as a result.
jim
ya know, that's exactly what i thought the first time i had the frame screen out-- what the heck is this thing going to catch that won't have already broken the motor? let me say this, if there's something in that screen, look at both sides of the engine for the connecting rod sticking out. my guess is that during r&d stress testing, the oil pump rotors kept losing teeth, and this screen was used to prevent the engine from detonating as a result.
jim
Posted 09 July 2001 - 10:24 PM
JohnnyG,
I have been told by a dealer mechanic the screen's primary purpose is in case you drop something into the engine while either checking the oil or filling it. I don't believe that is what the Yamaha engineers intended. As far as I can tell the oil pump is made up of two gerotor elements. One element is for pressurized oil and the other is for scavenge. The oil that goes through the pressure element is prefiltered. The scavenge oil does not get filtered. It is quite possible that you could get a chunk or chunks of metal large enough that gets picked up by the scavenege element and is sent up to the frame reservoir. The frame screen will allow for a good deal of trapping and still let oil get through to the pressure draw side. Otherwise the pressure line would potentially clog and the engine is toast. If the chunks are large enough to jam the scavenge gerotor it has a dowel pin which will shear allowing oil pump drive shaft to continue spinning. The engine casing will fill up with oil and cause a lot of churning and viscous losses but you still have a pressure pump and some oil for cooling and lubrication. Hopefully, a rider would notice the tremendous viscous losses (oil is incompressible) and stop the engine to figure out what the hell went wrong. A pull of the dipstick would reveal no oil (it is all in the case). The engineers wanted some redundancy for a good reason.
Again this is my best assesment of why the frame screen is there and I would encourage others to add their thoughts.
Also, I agree with Sunruh in checking it once or twice a year. It seems possible that it could partially clog and cause increased oil churning and pressure pump cavitation, both of which would not be good for engine compnent life.
Gear_Head
I have been told by a dealer mechanic the screen's primary purpose is in case you drop something into the engine while either checking the oil or filling it. I don't believe that is what the Yamaha engineers intended. As far as I can tell the oil pump is made up of two gerotor elements. One element is for pressurized oil and the other is for scavenge. The oil that goes through the pressure element is prefiltered. The scavenge oil does not get filtered. It is quite possible that you could get a chunk or chunks of metal large enough that gets picked up by the scavenege element and is sent up to the frame reservoir. The frame screen will allow for a good deal of trapping and still let oil get through to the pressure draw side. Otherwise the pressure line would potentially clog and the engine is toast. If the chunks are large enough to jam the scavenge gerotor it has a dowel pin which will shear allowing oil pump drive shaft to continue spinning. The engine casing will fill up with oil and cause a lot of churning and viscous losses but you still have a pressure pump and some oil for cooling and lubrication. Hopefully, a rider would notice the tremendous viscous losses (oil is incompressible) and stop the engine to figure out what the hell went wrong. A pull of the dipstick would reveal no oil (it is all in the case). The engineers wanted some redundancy for a good reason.
Again this is my best assesment of why the frame screen is there and I would encourage others to add their thoughts.
Also, I agree with Sunruh in checking it once or twice a year. It seems possible that it could partially clog and cause increased oil churning and pressure pump cavitation, both of which would not be good for engine compnent life.
Gear_Head
Posted 10 July 2001 - 04:30 AM
Nice writeup Gearhead. I agree with you and Steve, it would be impossible to clog this screen, and it is only for catching big chunks. It's not worth checking.
Posted 10 July 2001 - 07:55 AM
gear_head,
nice write up dude!
got a question though:
WHO would actually be able to tell "tremendous viscous losses" and what would be the clue to the rider while in a race?
nice write up dude!
got a question though:
WHO would actually be able to tell "tremendous viscous losses" and what would be the clue to the rider while in a race?
Posted 10 July 2001 - 01:56 PM
Sunruh,
I think you would notice a marked decrease in the bike's acceleration. I would estimate that if the case was full of oil you could lose as much as 7 to 10 horsepower. Not very noticeable in a 300 horsepower car but very noticeable in a motorcycle that puts out approximately 30 rear wheel horsepower. If I get some time I will make some loss calculations and report back to you. Dry sump bikes help eliminate these losses because the scavenge element has enough capacity to keep most of the oil out of the case and in the frame reservoir.
Gear_Head
I think you would notice a marked decrease in the bike's acceleration. I would estimate that if the case was full of oil you could lose as much as 7 to 10 horsepower. Not very noticeable in a 300 horsepower car but very noticeable in a motorcycle that puts out approximately 30 rear wheel horsepower. If I get some time I will make some loss calculations and report back to you. Dry sump bikes help eliminate these losses because the scavenge element has enough capacity to keep most of the oil out of the case and in the frame reservoir.
Gear_Head
