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XR650L Oil Cooler Ideas/Oil Pump Concerns

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I've got a big 2.75" x 11" oil cooler I'd like to mount on the XR650L in place of the big battery box under the left side cover.

 

The Sutton oil cooler sits below the height of the oil tank in the frame, but the XR680R Baja race bikes had an oil cooler up on the lower triple clamps, so I'll assume height on the bike isn't much of an issue.

 

What I'm wondering about is if the oil pump has enough power to move oil to the rear of the bike, through the cooler, and then to the oil tank. It wouldn't have to push oil up really far, just across to the rear, but I'm curious about the risk of air bubbles or whatever else forming in the lines if oil drains back past the pump. I'd assume it's ok, because the Baja race bikes had to move oil way up over the triple clamps.

 

Routing the lines is a whole different concern, right now I just want to be sure the pump can move enough oil around. Automotive engines get their coolers mounted all over the place, but those are wet sump systems usually.

 

See the lines on the XR680R running up to the cooler:

1992_Honda_XR600R_BAJA-2.jpg

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I'd be for testing that first before getting too serious.  

It would be a quick and easy thing to do.  Remove the breather hose from the side of the tank and let it pump out into the atmosphere (I'd temporarily extend it down and away from stuff).  Connect up your cooler system with the hoses just routed outside everything and start the bike just let the return oil dump into a funnel stuck in the dipstick hole.  You'll be able to watch it work and know in a second or two whether it'll do it at no risk of starving the bike for oil.  If all is well after a few seconds let it run and mess with throttle and such and you'll know in a few minutes whether or not it will do it well and if it can actually run that way safely.

Edited by Hollerhead
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     :facepalm:   And where , dare I ask , do you think the oil is going to go , if not back into the tank ? You could run an oil line across your yard and back and the oil will still come out into the tank.

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     :facepalm:   And where , dare I ask , do you think the oil is going to go , if not back into the tank ? You could run an oil line across your yard and back and the oil will still come out into the tank.


Good question, I was thinking maybe to the 4th dimension or wherever things go when I misplace them.

Either way, I just wasn't sure how sensitive the system is even though it is on a big dirt bike
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5 minutes ago, JoeRC51 said:

     :facepalm:   And where , dare I ask , do you think the oil is going to go , if not back into the tank ? You could run an oil line across your yard and back and the oil will still come out into the tank.

Search "friction loss in hydraulic systems".  It may help you understand his concern and your lack of understanding of what may happen.

Edited by Hollerhead

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It's a low pressure , low volume oiling system. 3/8'' oil hose is roughly 20% larger I.D.  than the stock steel lines. The oil pump is a gerotor type pump , NOT a centrifugal. As an aside , the GB500's oil tank is under the seat. My own XR has approximately 5 extra feet of oil lines connecting the two oil coolers  ,  but you just blither on HH.   :lame:

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As long as theres pressure! Joe you tested your yard oil line? I wear mine on a gold chain...bliiiing... What temps are you reaching that you need a way out there oil cooler...? Sounds like overkill to me though. A Lockharts done me just fine. If it gets one leak and you're way out, youre effed. Or be ten miles from home and not even notice the leak. Dont want oil anywhere near the rear tire.

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You don't even need an oil cooler anyway. That motor will run at 265 degrees all day long. 
 
WFT did you do to that gas tank ??


Not my tank, that's the one on the Baja bike from the 1990s

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21 hours ago, JoeRC51 said:

It's a low pressure , low volume oiling system. 3/8'' oil hose is roughly 20% larger I.D.  than the stock steel lines. The oil pump is a gerotor type pump , NOT a centrifugal. As an aside , the GB500's oil tank is under the seat. My own XR has approximately 5 extra feet of oil lines connecting the two oil coolers  ,  but you just blither on HH.   :lame:

  • Low pressure and volume is exactly why I recommend giving it a quick try.  
  • Hose and tubing have completely different loss characteristics not to mention the loss from additional fittings. 
  • Pump design doesn't matter one way or another. 
  • The GB uses a different pump, has much shorter lines than the OP's idea will use and those lines are directly attached to the tank without passing through a cooler.

You don't know it will be fine.  You speculate it will be fine.  It may but it may not.

 

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1 hour ago, JoeRC51 said:

:facepalm: Seriously , do you EVER get tired of listening to yourself blither ?

  • The GP did have the oil tank under the seat though...so you nailed that.  Not that it pertains in any way to the original post. 
Edited by Hollerhead

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i ran some 3/8 copper tubing out back around the rear fender and back to radiate heat, it helped a lot. since then i use a trans oil mounted on the forks, works about the same but doesnt burn my hand when pulling the bike out of where i shouldnt have been...

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