Priming the oil pump?

66 replies to this topic
  • machman

Posted November 01, 2007 - 06:49 AM


Sweet, my plan exactly. Can you tell me in more detail how you hooked the hose up? and what size it was?

  • martinfan30

Posted November 01, 2007 - 07:47 AM


Sweet, my plan exactly. Can you tell me in more detail how you hooked the hose up? and what size it was?

the hose is just 1/2 in. ID heater hose you can get at any part house. i just held the end of the hose on the fill hole and blew while waitng for the oil to squirt out of the oil feed pipe.

GD, that doesnt sound right!lol

  • Denn10

Posted November 01, 2007 - 09:12 AM



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  • t350

Posted August 12, 2015 - 03:42 PM


Ok guys a year or so back honda sent us a service bulliten on priming the 650l oil pump. They advise you to remove the oil fill plug and break loose the oil bolt in the head that you use to originaly check for oil pressure. Now remove the spark plug wire and take compressed air and pressurize the frame through the oil fill hole and while pressurizing the frame turn over the engine with the starter until oil starts flowing from the oil pressure check bolt. It dosn't take alot of air pressure so don't go crazy. Hope that helps

I know this is an old Post, but I could not prime my pump, and this information was extremely useful.  So BUMP!

  • XR650L_Dave

Posted August 13, 2015 - 01:40 PM


To add to the priming lore, if doing a rebuild on many engines they say to pack the oil pump with white grease or vaseline.

Not sure if that'll help on the L-pig.

  • garthr

Posted August 14, 2015 - 05:12 PM


maybe some trojon heating oil to get it going? just kidding, i add some compressed air to the oil tank hole to get it moving.

  • Onederer

Posted August 15, 2015 - 06:43 AM


To add to the priming lore, if doing a rebuild on many engines they say to pack the oil pump with white grease or vaseline.

Not sure if that'll help on the L-pig.


The XL600R, NX650, XR600R, XR650L and XR650R all use a gerotor oil pump, there is no reason to pack them with grease.


That is throwback logic from decades ago, mostly applied to automobile engines and vintage motorcycles that use an external gear oil pump. Even then, the proper way to prime the oil pump and oiling system on most automotive engines is to remove the ignition distributor and operate the oil pump with an electric drill for several seconds after achieving oil pressure. For engines that have a remote oil pump or there is too much vertical lift for the unprimed pump, a pressurized vessel containing oil is connected to the engine's oiling system via an external port, usually through the pressure gauge port, then oil is forced through the system.


When packing an oil pump with grease is discussed, many people like to point out that whatever they use (lithium grease, petroleum jelly, etc.) dilutes with the engine oil when hot, or the viscosity is greatly reduced when hot. The first start of a rebuilt engine is the most critical and the engine heat will not be sufficient to affect whatever type of grease or thick lubricant until past a minute or more, and that is plenty of time for insufficient oil flow to damage new parts.


Anyone can look at the external oil line on a RFVC engine and see how narrow it is. How well is a cold, thick grease or lubricant going to flow through that? That line is designed for the engine oil weights specified by Honda, it's not for pumping grease through.


During an engine rebuild and before oil pump installation, the oil pump should be submerged in engine oil and manually rotated a few times. Even though some will leak out during installation, in most cases, the pump should prime within a few seconds after starting. Don't forget, there is a head of oil above the oil pump, it's not like it has to lift oil.


Soaking the oil filter and filling the filter cavity with oil will help oil flow reach the cylinder head quicker too. It's not something needed during a regular oil change, but for a rebuilt engine's first start, anything that hastens oil flow is good. It's easy to fill an automotive, vertical canister type oil filter, but not so much the XR cartridge type filter.


In some cases, alternative methods may be required, like using air pressure, but I wouldn't consider that the norm. As some people have experienced, using air to force oil through the system may circumvent a problem, like a twisted oil hose. That can cause extreme wallet discomfort, possibly even spontaneous wallet combustion.

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