What is optimal running temp?

[81xsproject]

What is the optimal running temp for these bikes? I want to get an oil cooler thermostat and I have heard some conflicting temps. The lockhart thermo's are set for 160-180 degrees F, but another member stated that it should be in the low 200's. I can get one for that range, but I want to be sure first.
JC

[pggg]

81 will a thermostat make any difference? My oil cooled XS on the road at 60mph runs at 130C on the cylinder head so I suppose the oil temp must be about that too. The optimal running temp does that mean optimal power? Does thin oil give more power? Thick oil must add a bit of drag. Maybe oil coolers slow these bikes down. Optimal running temp might be any temperature once warmed up. When the oil boils it's too hot!

[81xsproject]

Its more the climate where I live. It can be cold in the mornings and hot in the day. Plus it lets the engine warm up much quicker. A more consistant running temp can only be an improvement.
JC

[81xsproject]

still need to know

[GNEPIG]

hi, i work on large air cooled motorcycles, when we set the hot idle on the fuel injected modles we warm the engine up to 250 deg f. this seems to be the optimum temp for an in line v twin motor whos desine is set back in the 1930s
if these motors handle 300 deg temps all day long your xs in line four will deffenintly take it. in fact its been taking the heat for the past 23 years and still runs good! doesnt it dont know many harleys that are that old with as many miles that havent been rebuilt at least twice


hope this helps

[81xsproject]

OK, so my point to this thread was simply to find out what the smost efficient running temp. I am sure that having a more constant running temp would result in a more efficient opperating engine. More importantly, I want to have the engine warm up faster on these cold mountain mornings. My old bike took a long ride before the thing really warmed up if it did at all. I don't want to have that with this bike.
JC

[GNEPIG]

i would get the one for 200 degrees it will let your motor warm up naturaly than your cooler kicks in for the extreme heat

[GNEPIG]

hi, i would like to state that the numbers that i had given in my previous statement were for the actual engine temps taken from a sensor in the heads not the actual oil temp......the optimum oil temp is right about 200 deg f + or - 10 deg....over 220 f would be over heating

the next tool truck that comes by i will purchess the expensive laser temp guage, take my 1100 out for a nice 20 mile ride and take some measurements.....the oil filler hole might be large enough to get the pointer on the oil that is pooled around the sight glass ....of course their are veriables to consider- like the differances between our bikes, rider weight, how we ride, the tarain [hills compaired to mountains] and the temp of the climate
but this will get us close

[81xsproject]

thanXS,
I have a lockhart air cooler on mine (obviously since I am looking at thermostats). I don't know if that makes a difference.

[GNEPIG]

ok, i bought the expensive laser thermometer yesterday .....
bought it from the national tool guy...its called Infrared Therometer W/Laser part# 52224 cost $89.
after playing with the cool new laser toy for a while yesterday and today i have determined that it is pretty close to being accurate... also checking it against another thermometer they both seem to concur...

went for a ride today to see what the temp range of the motor oil in my 1979 xs11 special would be
the local area temp at the time i started was 76 deg f...
I checked the temp of the oil before starting it ,74 deg
i rode around town for about 30 miles @ an average speed of 35 mph... stopping every 10 miles to check and every time the thermo stated the oil temp was 195 deg f... then took a ride on the interstate, went 20 miles @ an average speed of 70 mph stopped and checked it was 195 deg. i had gone 56 miles today, the last 6 miles were easy with an average of 50 mph....no stoping [the traffic light gods where with me] until i pulled in the driveway...
the oil temp then was 175 deg ...also the ambient temp of the area had dropped to 72 deg f by then
so what this tells me is unless your pulling alot of weight and pushing alot of air [like the guys with big fairings and saddle bags full of bowling balls and beer kegs] you don't need an oil cooler!
but if you gotta have one or your bike came with one I still suggest you get the thermostat rated @ 200 deg


hunt n peck hunt n peck, man is my finger tired!

[John]

Remember, the oil also performs some of the cooling of the engine, so the cooler it stays, the more efficent it will be in cooling. I have noticed that the OEM cooler on the XS850, and the 81H have no thermostat from the factory. I have had a few different coolers on my bike since I bought it. I now have a Lockhart cooler, and I elected to not use the t'stat with it. As many of you have heard, it gets hotter than hell here in Texas in the summer time, so I figured that by not using the t'stat, then that is one less chance of the thing not working and staying in the bypass mode. My previous cooler was OEM from an XS850. It didn't bolt to the frame on my bike like it did on the 850, so I attached it with tie wraps. There was no t'stat in the that system, so I figured if that's the way Yamaha built it, who am I to deviate from their system? They know a whole lot more about it than I do.

[Pat Kelly]

I too have an OEM oil cooler from an XS850 that will be going on my MN Special.
Reading this post got my looking at the adapter housing.
There is a spring-loaded bypass in the housing that lines up with one of the hose fittings (right side fitting). This right hose comes from under the plate (filter side).
This valve will allow oil to pass from the block to outside the filter element but not back the other way.
The left hose opening is open to the upper (engine) oil.
Does the oil flow out from the filter bolt or is oil drawn into the filter bolt?
I may experiment and put the plate in boiling water to see if it thermostatic ot pressure activated.

[Pat Kelly]

PS.
I am not going to install this cooler until I make a shroud for it. It is ugly.

[TopCatGr58]

Hey there Pat,

The Oil is not "drawn" up into the bolt, it is pushed up into the bolt, the oil is under pressure coming out of the pump, and enters the oil chamber thru that 1/2" hole in the rear portion of the filter chamber, flows thru the filter, and then into the bolt where it is pushed up throughout the rest of the motor!
T.C.

[Pat Kelly]

Thanks TC!
The valve is not thermostatic so it looks like it allows the oil to by-pass the cooler should the cooler become plugged.
Makes sense.
The kids are blackmailing me to tell Mom I was cooking motorcycle parts in a pot on the stove after she left for work. They got icecream.
So..... if I could make the spring (coil) heat sensitive where it was loose when cold it would allow cool oil to not go throught the cooler. When the spring warmed it would close the valve (but still by-pass under XSive pressure) and route oil through the cooler.
Too much trouble. My E has a Lockhart with no valves at all and it works fine.