Oil cooler install

[plane_ben]

Deceided to do an XSJohn oil cooler mod to my chopper. Located two XS750 oil coolers complete with lines at the local junk yard, then went to town. First I flattened out the stock mounting plates that were for the XS750, and filed out the holes so I could get an upright angle more in line with the frame. I mounted the oil cooler on the two front mount bolts on the out side of the frame rails.

Once that was done, I made the top end oil restricter, and opened up the old restricter union that screws into the case. Here are pictures of the parts. Left is the opened restricter union, middle is the new restricter piece, and right is the old restricter union for comparison. Then the top end oil line with restricter JB Welded in, and the bottom oil line installed. Just need to go get some suitable 1/2" I.D. oil line, and hose clamps tomarrow and install them. Should be ready to go. I also filled the oil cooler with oil.

 

[nj1639]

OK, I've got the 750 cooler with the lines.....how or where did those connectors on the cooler come from, are they under the stock hose clamps?

 

[plane_ben]

I just cut the outer metal crimp 180 degrees apart, and peeled it open to remove the stock rubber oil line. I'll do some pics on my second cooler tomarrow and post up how I did it. Didn't think of pictures soon enough on this one.

 

[pamcopete]

plane ben,

Opening up the re-stricter is going to reduce the oil flow to the main bearings on the crank. Also not all of the oil from the oil pump will go through the cooler so the effectiveness of the cooler will be minimal.

A better way to connect the cooler is by using the oil galley taps in the front of the right side engine cover and return the oil to the right side oil screen cavity.

Here is a pic of MikesXS cooler installed on my '81/H:

I tapped into the outlet from the oil pump and returned via the oil screen side cover.:

It's important that the oil flow from bottom to top to ensure that all the cross tubes are filled with oil:

An even better scheme would have been to mount the cooler with the inlet / outlet pipes on top.

Here is a diagram of the oil cooler circuit:

I plugged the oil passage into the screen filter cavity with a dowel held in place with a set screw. It was a tight fit, and there is no need to make it leak proof. 100% of the oil from the oil pump will go through the oil cooler with this arrangement.

I mounted it low to avoid interfering with the air flow to the cylinders. I moved the horn for the same reason.

I had a similar arrangement on my faithful;l '78/E that went all the way to 80,000 miles without an overhaul. I think that the oil cooler and changing the oil every 1000 to 1500 miles contributed to that long life.

 

[nj1639]

Ben,
I found the connectors right where they should be. I have some angled alu for the mounting bracket- as I didn't recieve the stock mounts with the cooler. I also need to get the lines for distribution and then make up the restrictor.
On the upper end restrictor.....what did you use and how did you shape it.
John used a side cooler in conjunction with the top end cooler.

 

[650Skull]

plane ben,

Opening up the re-stricter is going to reduce the oil flow to the main bearings on the crank. Also not all of the oil from the oil pump will go through the cooler so the effectiveness of the cooler will be minimal.

Pete The restrictor is opened up so the oil will flow into the cooler easier. The oil flow is still restricted between the cooler and head by making another reducer and installing between the cooler and head. a quote in XSjohns own words.

.My design does not force more oil to the top...it just cools the oil...There is a small amount of drag in the oil flow because of the extra distance of the tubes and gravity ...Tried the original size restriction size and found it too small... Not good.

"Original restriction was .116 thou at the base of the oil tube which needs to be opened up say .200 (could be 3/16 could be 1/4 inch) so the oil will move to the cooler unrestricted the restriction should be .125 on the "going to the head" far side (field side) of the cooler ....Don't change my design it works perfect...............................In other words the oil follows to the cooler unrestricted form the main oil galley...Then the .125 restriction holds back the correct amount of oil to lube the top end correctly with 120-140 degree oil............

 

[pamcopete]

650skull,

OK. That's better, but you will still not get 100% of the oil from the pump. The oil pressure in the XS650 is minimal once the engine heats up. It is zero at idle and only 3 to 7 PSI at 3,000 RPM's so there is very little flow in the feed tube to the head.

 

[plane_ben]

On the upper end restrictor.....what did you use and how did you shape it.

I used a piece of aluminum bar stock and turned it in my lathe. I made a lip on one end so it couldn't be pushed farther in the top end line, and also abit larger diameter so it will seal on the hose better to.

Pamcopete, I will do your style mod on my next engine/project. As it's a little cleaner looking after the install. On my next oil change I'm going to pop the clutch cover and massage the oil pump cover as well. You remove material off of the oil pump cover until you get .002" clearance. XSJohn reported that this gave him increased pump flow.

BTW, I love your ignition. My bike is a one kick starter.

 

[plane_ben]

Put my lines on today. Started up to make sure no leaks, and check my oil level. Then I took my tank and top mount off, fired it up and cracked the two top end oil lines. Oil flow is plenty strong and looks the same as when I tested after the rebuild. After I cleaned up and reinstalled the tank, I went for a quick ten mile ride. Before in the spring my right Cyl temp was running 205 to 210 average. In this hotter weather I got 195 right at the spark plug. Seems like a worthwhile mod to me. I'm happy.

 

[650Skull]

650skull,

OK. That's better, but you will still not get 100% of the oil from the pump. The oil pressure in the XS650 is minimal once the engine heats up. It is zero at idle and only 3 to 7 PSI at 3,000 RPM's so there is very little flow in the feed tube to the head.

I'm sure that this mod is designed to cool the head first and any cooling benefits, (xsjohn had an external oil filter), after that was a bonus. Seems the combination of the top end cooler and the external filter may have achieved this, his thinking was the oil cooler set up, plugged into the cases as yours pete, would let the oil going to the head be warmer before it got there and not do the cooling of the head where he was looking for the gain.

The other thing is to be careful, when doing some of xsjohns mods, because he done a lot of tinkering and the end product from that is a sum of the mods that got the end result

 

[pamcopete]

650skull,

Well, that's probably correct. You would have to have a very large oil cooler to really cool down all of the oil from the pump, so perhaps his thinking was to at least cool the oil going to the head.

But, the overall purpose of cooling the oil is to maintain its viscosity for the benefit of all the moving parts in the engine. I had oil coolers in the 6 cylinder engines of my airplane that were not much bigger than the cooler on my bike and I found out how well they worked when a mechanic left a shop rag on top of one of the coolers. I had to shut down the engine because the oil temperature was getting way up there, but of course the airplane had 185 MPH air blowing through the cowling and the oil cooler, so it really did a job.

I might try Johns idea and reroute the lines to the oil feed tube with the theory that the cooler is too small to really do any good for all of the oil, but large enough to provide a difference in the head temperatures as plane ben has discovered.

 

[nj1639]

I finally got mine plumbed together,,,,,,I'll post some pics later.