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XR400AF build oil pump volume?


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I’m building a bike that I wish Honda would have done.

The bike is a CRF450 chassis with a 400ex engine.  Basically an XR400 with electric start.

My question is, “How much oil does this motor pump out, up to the frame, in a given minute?”

Short of just pulling the line off and starting the bike and watching to see how fast it can fill a quart bottle.  

Does anyone know?

Reason for asking this question is because I’m building oil tanks in place of the wet frame that was found on the XR400 bikes.  With the two tanks that I’m placing on the CRF450 frame in place of the radiators; I need to do a cross over from one tank to the other.

I would like to run the bike with both tanks more or less full, in order to take advantage of the most cooling I can get.  I just don’t want to starve the engine for oil waiting for one tank to fill up to a high cross over.  On the other hand I don’t want a low cross over and lose out on the cooling ability of the tanks if they’re going to be mostly empty while the bike is running.

Does anyone have a realistic idea on how to get a cross flow effect without taking forever to get oil to the return line?

A few videos can be found of it on YouTube under “XR400AF” if you care to watch them and give me any ideas for oil line/tank.

Thanks in advance for any help.

948FCDEF-4734-4D82-9933-10563E2BE133.jpeg

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3 hours ago, 400yzturbo said:

I’m building a bike that I wish Honda would have done.

The bike is a CRF450 chassis with a 400ex engine.  Basically an XR400 with electric start.

My question is, “How much oil does this motor pump out, up to the frame, in a given minute?”

Short of just pulling the line off and starting the bike and watching to see how fast it can fill a quart bottle.  

Does anyone know?

Reason for asking this question is because I’m building oil tanks in place of the wet frame that was found on the XR400 bikes.  With the two tanks that I’m placing on the CRF450 frame in place of the radiators; I need to do a cross over from one tank to the other.

I would like to run the bike with both tanks more or less full, in order to take advantage of the most cooling I can get.  I just don’t want to starve the engine for oil waiting for one tank to fill up to a high cross over.  On the other hand I don’t want a low cross over and lose out on the cooling ability of the tanks if they’re going to be mostly empty while the bike is running.

Does anyone have a realistic idea on how to get a cross flow effect without taking forever to get oil to the return line?

A few videos can be found of it on YouTube under “XR400AF” if you care to watch them and give me any ideas for oil line/tank.

Thanks in advance for any help.

948FCDEF-4734-4D82-9933-10563E2BE133.jpeg

Are talking about doing something similar to     an “ accusump “ this something hot rod engine builders do for a cheap version of a dry sump system , I know this idea works better in off-road buggies and trucks and hot rod vehicles then a dirt bike , are having custom oil coolers made ?

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The engine is a dry sump setup already.  From the factory the engine pumped the oil out into one tank that consisted of the frame under the gas tank and the front down tube.  Where it was a single tank there wouldn’t be a problem.

In my case I’m trying to run two tanks.

Ive included a pic of the two ports coming out of the engine.  The upper port is the oil leaving the motor and the lower is the return.

then the other pic is the two tanks I’m building.

6471A8F9-A962-4CE7-90F6-A6F8F116205D.jpeg

9923428E-9884-4A2D-8E47-85773B7DEDCF.jpeg

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2 hours ago, 400yzturbo said:

The engine is a dry sump setup already.  From the factory the engine pumped the oil out into one tank that consisted of the frame under the gas tank and the front down tube.  Where it was a single tank there wouldn’t be a problem.

In my case I’m trying to run two tanks.

Ive included a pic of the two ports coming out of the engine.  The upper port is the oil leaving the motor and the lower is the return.

then the other pic is the two tanks I’m building.

6471A8F9-A962-4CE7-90F6-A6F8F116205D.jpeg

9923428E-9884-4A2D-8E47-85773B7DEDCF.jpeg

What size is the factory oil cooler/ tank ? And what size have you just made ? I would have keeped the size close the factory size to keep the volume and pressure the same , found a pic of a cheap upgrade to a 400ex cooler and I now see the factory oil tank and cooler and the small factory cooler it has and that cheap cooler with computer fan addition doesn’t look like that engine need a lot of cooler  , I read on a 400ex riders forum the Idling pressure is  4 or 5 psi and 1/4 throttle is 10psi and 3rd gear full throttle is 20psi ish so id say it doesn’t push that much oil 

Beautiful work though I like the idea & we’re its going love to see the hole build in a thread 

 

804886A5-0286-462D-A6EB-910277A1AFED.jpeg

54C51D4C-19F9-4129-A5C7-E13A1D0E59E8.jpeg

Edited by DTM Industries
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According to a rough calculation, the left tank should hold 1.25 quarts, while the right tank will hold 1.125 quarts.

As a rough guide I’m looking at 2.375 quarts where stock on the XR400 is approx 1.9 quarts.

I wouldn’t say I have too much extra oil capacity.  

My tanks that I’ve built are open tank so there won’t be any extra restriction to flow.

Im not concerned about the oil being too cool.  With this setup I don’t see that even being a possibility.

 

I was thinking of feeding the left tank from the bottom or the top.  Then having a cross over up high from the left tank to the right.  In this manner the right tank could be constantly full; taking advantage of all the surface area the heat sink has to offer.

Still my concern on having a high cross over to the left tank from the right is the time it takes to fill the right tank. As the right tank is filling it leaves the left tank possibly empty for a short time.

With the left tank possibly being empty for a time could starve the motor for oil on startup if the bike has sat and all the oil has drained down to the crank case.

I could just do a high and low cross over and deal with the lack of cooling.  

 

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The original frame acts as an oil holding tank - return oil into the top - gravity feed to pump out the bottom.

So - Have a connection between both tanks at lowest level so they act in unison as one tank.

Route your oil return to the top of either of your tanks.

Have a gravity feed from the bottom of either of the tanks to the feed side of the pump. 

It doesn't matter which way round you do this as both tanks act as one due to their connection at their lowest point.

Both tanks require a vent/breather at the top.

 

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I've been following your build on youtube (guys y'all need to check this out - he's up to Part 5)

All I can say WOW!!!!!!!!! and GREAT WORK!!!!!!!!!

Please keep up the build and give us feedback on the results. The oil reservoir is minor compared to what you have done. My .02. CR80's (and I'm sure others) had one radiator. What is the problem with cooling from the one side and making a "dummy" for looks on the other.

 

 

Edited by johnmere
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Hi, I think I can answer your question.

I would run a cross over from tank to tank at the top and bottom.  Oil in on one side (tank 1) should be up high, and oil out on the other (tank 2) should be low.  The thermal effects of the oil tanks to the frame will be minimal but you should isolate them on rubber like the oem radiators to protect against vibrations, single cylinders vibrate a lot.  I do not see what you have done as a cooler, but more like an oil tank in a cool location.  Size your cross overs, inlet and outlet the same diameter as the OEM 400ex tubes and the pump shouldn't care.  I would not worry about flow rate if you size them the same.  The OEM xr400 setup had a vent tube that went from the frame to the crankcase I believe, I think you need some sort of PCV vent to crank case in your setup as well.

Hope that helps...

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This project has been a head scratcher at times.  It seems that around every corner there is yet another challenge.  

First challenge was getting the motor to fit in the frame.

Second challenge, getting swingarm to clear the engine once bolted in.  It’s tight, so tight I hope it doesn’t cause any problems.

Then came the engine mounts.  They all had to be rearranged.

Once engine mounts were sorted out, it was then the carburetor.  I wanted the pumper style carb but had no room for it.  

Now the carb is in and I still have to figure out how to get an air boot attached to the inlet side of the carb.  The shock body is a little close.  I’m still scratching me head on exactly how the link between the carb and the airbox is going to be.

Then the oil tanks fitment challenge which then brings up oil supply lines and return line routing.

Cant forget about the gas tank.  Since the engine goes so far up into the twin spars, the original tank was not even an option.  I had to build an aluminum tank.  With the idea of an aluminum tank, I needed a gas cap.  That lead to having a machine shop custom build me a filler neck that used the stock gas cap.  

I still haven’t even figured out how I’m going to route the electrical.

So like I said, challenge after challenge.

Im sure there are going to be many more challenges in the final stages of this build.

One of the bigger ones is my funding department (my wallet). 

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On ‎6‎/‎26‎/‎2018 at 0:38 AM, 400yzturbo said:

 

Im not concerned about the oil being too cool.  With this setup I don’t see that even being a possibility.

 

.  

 

You should be concerned.

Cool oil hitting hot engine parts will  sludge up real quick.

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I know cold oil on a hot engine isn’t good.

Im just worried that the oil isn’t going to get cooled enough.

The tanks I built are built just like a typical tank, so they won’t have the same cooling like a typical oil cooler would.

Ill for sure to keep an eye on oil temp once I get it to that point.

 

 

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