XR650L: Spud's Oil Cooler

Discussion in 'Thumpers' started by Spud Rider, Apr 14, 2012.

  1. Spud Rider

    Spud Rider Long timer

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    I got a little wet at one point, but I still made several, freeway test runs of my oil cooler today. My latest fender modification was successful. Riding the same stretch of freeway that yielded a high oil temperature of 279 degrees yesterday, my high oil temperature was 248 degrees today. :D

    I also rode the same section of freeway that yielded a high oil temperature of 255 degrees without my front fender mounted. Today, with my modified fender mounted, I reached a high oil temperature of 253 degrees. Riding back home along this same stretch of freeway, I encountered very strong headwinds that kept my speed at 75 mph while riding wide-open-throttle. My high oil temperature under these conditions was 235 degrees.

    This oil cooler installation works very well. :D Other than the XR650R C/S sprocket, I think this is the best modification I have made to my XR650L. :nod I am very pleased with the current configuration of my oil cooler; at this point I don't plan to make any further changes. I will certainly report if I encounter any difficulties with this installation.

    Another forum member promised to loan me his XRs Only temperature gauge next week. After riding a few miles with his oil dipstick thermometer, I will report the difference in temperature between my temperature probe located near the engine, and the oil dipstick thermometer located in the oil reservoir. :deal

    Spud :wave
    #61
  2. JWhitmore44

    JWhitmore44 pistolero

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    Out of curiosity, what's your gearing? Are you running the 15/48 or did you go back to the 45 tooth on the rear?


    thanks
    #62
  3. Spud Rider

    Spud Rider Long timer

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    I'm currently using a 15T/48T sprocket combination. I will switch to 14T/48T sprocket combination after the snow melts from the mountain trails.

    I made all of my freeway runs at 75-85 mph, which was near wide-open-throttle operation at approximately 5,000 above sea level, fighting Idaho's springtime winds.

    Incidentally, please note, I saw a 31 degree drop in oil temperature yesterday merely by cutting a hole in the front fender. This temperature reduction was observed after my oil cooler was installed with a drilled fender. :eek1 Therefore, my oil temperature reduction from stock configuration must be even higher than 31 degrees. :deal

    Spud :beer
    #63
  4. JWhitmore44

    JWhitmore44 pistolero

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    With the 15/48 mine's starting to wind up pretty good. I added the XR400 cooler to mine. I'd guess about a 25 to 30 degree drop. I'll be curious to see what happens with mine when the temps get above 80 :) There is a person on the XR400 forum claiming that there isn't really enough air flow on the XR400 oil cooler where it's mounted. That all it's cooling is done by convection. He was also trying to validate that his new headlight configuration, that blocks air flow, wasn't going to make the bike run hotter. I do like your cooler setup though.
    #64
  5. Spud Rider

    Spud Rider Long timer

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    Thank you, Jay.

    I'm convinced airflow is one the most important factors. :nod My oil cooler has 16 square inches of surface area, and all of it is perpendicular to unobstructed airflow under the fender. In addition, my oil cooler is mounted away from the engine block and exhaust header. I think all of these factors make a significant difference in an oil cooler's ability to dissipate heat.

    Spud :beer
    #65
  6. LexLeroy

    LexLeroy Mr. Spoil Sport

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    You're wrestling with the same set of trade-offs that haunted my eventual placement decision. I decided that if I was going to block off any airflow to the engine the least hurtful spot was the cylinder below the head. The supermoto front fender that I use sucks for protecting the headlight from tire spray but it's got some nice slots in the rear for directing airflow to the cylinder head.

    At some point I'll replace the stock headlight with a Buell Uly unit that I found. The bracket for same will include mounting an Earl's oil cooler atop the front fender in Dakar fashion, but I didn't want to get bogged down in a major re-engineering effort with riding season aproaching. For the time being these little Baker Precision units are just fine - cheap, stout, easy to plumb and pretty easy to mount. If I wasn't such an anal-retentive nose-picker I'd be happy as a clam with what we've got, but hey, I like wrenching on these pigs almost as much as riding them. :evil
    #66
  7. Spud Rider

    Spud Rider Long timer

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    After rereading an earlier post, I now think someone believes I am blocking airflow to the cylinder head; that's not the case. My oil cooler is located well above the fins on the cylinder head. Also, I have trimmed the rear of the fender to prevent wheel impacts, so my engine is receiving more air than ever before. :nod

    Engine oil temperatures are the only objective measure of how hot the engine is running on an XR650L. If oil temperatures drop, the engine is runner cooler. I'm sure my oil cooler was radiating heat, and lowering engine temperatures a little even with an unmodified fender. Cutting a hole in the front fender increased airflow over the oil cooler, and reduced engine oil temperatures another 31 degrees. Therefore, I'm confident my oil cooler is reducing engine oil temperatures greater than 31 degrees, Fahrenheit.

    It will be interesting to compare the temperature difference between my temperature probe, and the XRs Only dipstick thermometer. :nod I also plan to cover my oil cooler with duct tape, and compare temperatures with my current configuration. :deal

    Spud :wave
    #67
  8. RoadHawg14

    RoadHawg14 CRASH

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    Do you have images of your Oil Cooler installed?
    #68
  9. LexLeroy

    LexLeroy Mr. Spoil Sport

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    Now that you've proven that the 4 x 4 cooler works as well as the 4 x 6 cooler that I used I'll probably go out to the garage this afternoon with a lawn chair and a six-pack, stare at the bike and think about re-doing my oil cooler. The 4 x 6 unit just didn't seem to have adequate clearance tucked against the down tube, either in the horizontal or vertical orientation. The 4 x 4 unit, however, seems to fit just fine.

    [​IMG]

    Sideways mounting addresses any questions that others have raised in the past about adequate cooler draining (ports facing upward) or "airlock" by-passing any internal cooler passages (ports facing downward). Thanks... I think. :cry
    #69
  10. Spud Rider

    Spud Rider Long timer

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    :rofl

    You're welcome. :nod

    Spud :lol3
    #70
  11. michael.brat

    michael.brat Been here awhile

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    Hey Spud, great to see you've installed an oil cooler! I haven't been on adv for a few weeks due to time restrictions so I just wanted to leave you some info based on my testing of the 4x6 cooler in the same spot during my USA trip. Also, I'd like to compare it to the relocation to above the skidplate.

    Will the tire bottom out on the cooler?

    For me it did. My cooler location may have been slightly lower than yours since it is a 4x6.

    [​IMG]

    This only happened once, and it nearly sent me over the handlebars since I hit a pothole very hard. No damage to anything really, just what you see below. (What you can't see is the cooler has a curve to it where the wheel bent it inwards)

    Otherwise, with the fender spaced down, the tire would contact the fender often and eventually ripped the screen off the fender. I do have a hard riding style though.

    [​IMG]

    Efficiency of cooling in that location?

    Great. Rarely saw above 260F in every situation encountered in 20k miles of riding around the US.

    Definitely better than the current location above the skidplate. My theory is that it's too close to the engine and acts like a heatsink. I doubt there is much airflow between the engine and the cooler with how I have it placed.

    I've hit 300F at technical riding on Steel Pass in Death Valley.

    [​IMG]

    Slotted vs Drilled for cooling?

    I feel that drilling the fender, even with large holes, creates too much turbulence and doesn't allow air to cleanly get to the cooler. It seem Spud has proven this with his recently trials.

    Slotting takes longer, but the right way is rarely the easy way.

    [​IMG]

    Mud on the oil cooler inhibiting cooling?

    Of course. If you notice higher temps, rinse off the mud and go on your way.

    For more info on the 2 cooler locations, visit my thread: http://www.advrider.com/forums/showthread.php?t=689875

    Mike B
    #71
  12. Spud Rider

    Spud Rider Long timer

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    Thanks for posting the feedback, Mike! :D My oil cooler is mounted about 4 inches higher on the downtube than yours was.

    Regarding the mud; I couldn't agree with you more. :nod If one is slogging through the mud, he doesn't need help from the oil cooler. If one is going to ride at high rpms, for an extended period of time after slogging through the mud, wash the cooler off with some water. :deal

    Spud :beer
    #72
  13. Spud Rider

    Spud Rider Long timer

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    A fellow inmate graciously loaned me his XRs Only temperature dipstick. Therefore, I was able to take a ride and compare the oil temperatures between my TTO Temperature Gauge and the oil reservoir.

    [​IMG]

    As you can see in the following photograph, the oil cooler receives an unobstructed airflow over the front wheel, and below the front fender.

    [​IMG]

    The above and below photographs also reveal the oil lines are well protected by the forks and their high location inside the outer edge of the fuel tank.

    [​IMG]

    The motorcycle must warm up a bit before the temperature of the oil in the reservoir stabilizes. :deal However, after the temperature stabilizes, the oil temperature in the reservoir is 25 degrees cooler than the oil temperature exiting the engine, when the bike is idling. After riding about 50 miles, I took the following photograph of oil temperatures with the engine idling.

    [​IMG]

    As you can see, the TTO temperature probe located in the oil line before the oil cooler shows a temperature of 225 degrees, while the oil dipstick thermometer shows a temperature of 200 degrees.

    After the engine is turned off, the temperature of the oil in the external lines and cooler quickly drops 30 degrees in several minutes. In contrast, the oil in the reservoir cannot radiate the heat as well, and the temperature remains elevated. I took the following photograph about 3 minutes after turning off my bike’s engine. The oil temperature in the cooler has dropped to 94 degrees, but the oil in the reservoir is 125 degrees.

    [​IMG]

    If you wait longer before starting the engine, the temperature of the oil in the external lines and oil cooler drops even more. After stopping to take some photographs and enjoy the scenery, I recorded the temperature difference in the following photograph. The temperature at the TTO probe is 97 degrees, while the temperature in the oil reservoir is 160 degrees.

    [​IMG]

    [​IMG]

    When pushing the bike to it’s maximum oil temperature, the temperate at the TTO probe and the oil reservoir are identical. Indeed, this must be the case. If the temperature of the oil in the reservoir is lower, the reservoir temperature must continue to rise until the two temperatures are equal, or a maximum temperature cannot be reached. :deal

    [​IMG]

    During most of my ride today, the oil temperature at the TTO probe was 10 to 15 degrees hotter than the temperature at the oil dipstick. The temperature difference is greatest at idle and low engine rpms. The temperature difference decreases as the engine load and engine rpms increase; the two temperatures are identical at the maximum oil temperature of the system.

    [​IMG]

    After exited the off ramp from an extended, wide-open-throttle run on the freeway, the oil cooler quickly drops the temperature of the oil it sends to the reservoir. Even after riding about ½ mile, and pausing at several stop lights, the following photograph shows my cooler dropped the temperature of the oil in the reservoir 28 degrees before I parked the bike outside Wal-Mart. The oil coming from the engine is 253 degrees, but the oil inside the reservoir is 225 degrees.

    [​IMG]

    Please note, in this instance, reading the dipstick thermometer alone would be deceiving, since the oil coming from the hot engine is still 253 degrees. It takes a short time for the cooler oil in the reservoir to quench the hotter oil still inside the engine. :deal

    I can easily keep oil temperature below 240 degrees if I ride at 65-70 mph on the freeway. When I push the bike continuously, wide-open-throttle for 40 miles or more, I can get a maximum oil temperature of 258 degrees, before the temperatures in both thermometers equalize. Running less than wide-open-throttle will always show the TTO temperature probe running at least 5 degrees hotter than the dipstick thermometer in the oil reservoir.

    Spud :wave
    #73
  14. Cumbacheech

    Cumbacheech XRated

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    Need to ask... how did you secure the wire mesh?:ear I want to put some slots on my CRF fender to add some airflow

    #74
  15. LexLeroy

    LexLeroy Mr. Spoil Sport

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    Excellent write-up... makes me wish that I'd held off doing mine until you'd finished yours and gotten those real-world numbers. Oh well. I'm just gonna' ride mine for awhile and hold off until next winter before I revisit the cooler issue, but your results clearly demonstrate that the 4 x 4 Baker Precision unit mounted high on the down-tube is an excellent and economical approach to getting oil temps under control.
    :clap
    #75
  16. Spud Rider

    Spud Rider Long timer

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    Thank you, Leroy. :D

    Spud :beer
    #76
  17. Spud Rider

    Spud Rider Long timer

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    I don't know how Mike attached his wire mesh. :dunno However, you can drill 4 or 6 small holes, and use plastic zip ties to attach the mesh to the fender, as I did. :nod

    [​IMG]

    Spud :wave
    #77
  18. michael.brat

    michael.brat Been here awhile

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    I zip-tied the mesh in multiple spots, then used this stuff: http://www.createforless.com/Loctit...719.aspx?utm_source=googlebase&utm_medium=cse

    Probably not the best stuff, but held well without having to surface the plastic. ~I usually leave the zip ties on for a week

    Here are some pics of the CRF230L fender I vented. Even though I don't have the cooler there anymore, I wanted to see if it made a difference in cooling by possibly getting more air to the head. Didn't notice any change in temps.

    (You'll see the adhesive in the last picture)

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    Mike B
    #78
  19. D-man

    D-man SALLGOOD

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    I am not a fan of tie wraps so got a little more permanent with rivets

    [​IMG]



    [​IMG]


    standard 1/4" hardware cloth, this has about 7500 miles and no issues, cant say it did much but it looks like it should

    dman
    #79
  20. Spud Rider

    Spud Rider Long timer

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    That's a nice job, Dave. :nod Where did you get the hardware cloth? I bought mine at CAL-Ranch for $4.99 a running foot. :deal I have enough 1/4-inch hardware cloth to last my bike a lifetime! :lol3

    Spud :wave
    #80