XR650L: Spud's Oil Cooler

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

  1. elsalvadorklr

    elsalvadorklr southern xr rider

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    hey spud the reason people have issues with fork caps, is because they dont put their THINKING CAPS on before removing them! wink wink...

    you HAVE TO make positively sure that you loosen the top pinch clamp bolts on both sides and sometimes even wedge delicately a flathead screwdriver in the slot to open up the clamp a bit to where you can easily and softly unscrew the caps, same for tightening....

    if your forks are stock youlll be amazed when you unscrew those caps off, you actually have negative "preload" on the springs, in other words they are loose in there, if the springs are well used a little shimiing or fork spacer under the cap and between the spring works to eliminate this issue

    just thought this might help a bit
    #41
  2. Spud Rider

    Spud Rider Long timer

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    Thanks for your input, Christian. :D I have USD forks on two other motorcycles. On one bike I will bottom out the USD forks occasionally. I think you're correct; the outer fork tube might not hit the lower clamp in that situation, but it comes pretty close. :wink:

    Thank you, Christian. Indeed, I always loosen all the top pinch bolts in the triple tree, and loosen the fork caps themselves, before I remove the forks for servicing. :nod

    I am very willing to remove the fork caps to test if the front wheel contacts my oil cooler. :nod However, it seems if I remove the fork caps, nothing will stop the fork tubes from compressing until the outer tube hits the lower part of the triple tree. Therefore, I'm not sure this test will give me the information I seek. If the fork cap remains screwed to the damping rod (as planned), will the damping rod still limit fork compression with the fork caps removed? :dunno

    Spud :beer
    #42
  3. elsalvadorklr

    elsalvadorklr southern xr rider

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    yes!

    thats the reason the service manual says to be carefull when unscrewing the lowers from the uppers...

    the rod can be damaged...

    I think this simple test at least will give you an idea

    and in reality its the fork springs and eventual coil binding that will limit your max travel, thats the reason people put stiffer springs, "top out" springs like 88-90xr600 forks have or preload spacers, again preload spacers is more of a cheap fix for initial travel in regards to fork dive when braking hard, not because you dont have enough slider length

    look at your bike and measure without the boots and see what you get lengthwise, Ill bet its more than 12 inches

    actual fork travel on our bikes is 11.8 inches...less when taking into account sag and all
    #43
  4. Spud Rider

    Spud Rider Long timer

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    Yesterday I decided to figure out how much the forks could compress before the front wheel impacted my oil cooler. I removed the front fender, placed my XR650L on a stand, and measured the free sag at 1-1/8 inches. Taking the bike off the stand, I measured the travel from the wheel to the bottom of the oil cooler at 9-1/2 inches.

    [​IMG]

    Adding the free sag to the last measurement, I got a total wheel travel of 10-5/8 inches. Therefore, the wheel will impact my oil cooler in the last inch of travel. I'm convinced 10-5/8 inches of fork travel is sufficient for the way I ride my XR650L, so I have decided my oil cooler is positioned high enough. :deal Incidentally, I raised my forks one inch when I installed my lowering link. Therefore, a stock bike would be able to accommodate maximum fork compression without striking my oil cooler. :nod

    Since the weather was nice, I rode my XR650L for 56 miles on the freeway, without the fender, to discover the highest level of cooling I could expect.

    [​IMG]

    I maintained 75-80 mph the entire time, and passed a lot of automobiles along the way. My oil temperatures did not exceed 255 degrees; I am pleased with this result. Of course, once I exited the freeway, my oil temperatures quickly dropped to much lower levels.

    [​IMG]

    I am going to trim my front fender a bit more, to ensure the wheel will not impact the fender before it would impact the oil cooler. :deal I will also drill a few more holes in the fender, and test to discover if the drilled fender allows cooling similar to a fenderless setup. If the cooling is significantly less with my drilled fender, I will cut a large hole in the fender and install some aluminum hardware cloth.

    Spud :wave
    #44
  5. Cumbacheech

    Cumbacheech XRated

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    Spud,

    Bike looks bad ass with no front fender... maybe a low front fender is in order... :evil
    #45
  6. Spud Rider

    Spud Rider Long timer

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    The kids were waving at me, CC. :wink:

    Spud :beer
    #46
  7. Cruz

    Cruz Lost but laughing.

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    Your photos show possibly the best place to mount your oil cooler, the same as Dakar Rally bikes, in that space below your headlight using flexible hoses. It gets clean air and is away from mud and debris and your front wheel.
    #47
  8. techforlife

    techforlife CDI REPAIR

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    Actually..........like just said,,a low fender would keep all the mud off the cooler.someone on the XRL thread has one,,i personally don`t really like the look.........but in this case it`d be ideal for airflow...

    B
    #48
  9. Spud Rider

    Spud Rider Long timer

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    Yes, a low fender would be ideal for airflow to my oil cooler. However, I don't like the way they look, either. Also, the low fender will clog up with mud, and stop the front wheel in sloppy terrain. :rolleyes

    Spud :wave
    #49
  10. Spud Rider

    Spud Rider Long timer

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    Speaking of airflow...when it comes to oil coolers, airflow is everything. :deal

    After finding the highest oil temperature my bike sustained without a front fender, I decided today to test a drilled fender. I drilled as many holes as I could, while still trying to maintain the structural integrity of the fender.

    [​IMG]

    After mounting this fender, I actually removed it, and drilled more holes on the outside edges. :deal Then I went for a ride on the freeway. Riding at 75-80 mph for about 30 miles, my oil temperature reached a high of 279 degrees. :rolleyes This oil temperature was 24 degrees higher than the 255 degrees I observed riding under similar conditions without a front fender, and I consider it unacceptable.

    If I didn't fully understand before, I certainly understand now. Maximum airflow is the key to keeping oil temperatures lowest. :deal Althought the drilled fender looks well ventilated, it is undoubtedly more than 50 percent blocked. :rolleyes Here are a few photographs of my bike after the freeway run.

    [​IMG]

    [​IMG]

    I decided this was my final ride with this drilled front fender. :huh

    [​IMG]

    After I arrived home, I cut a large square out of the fender, and installed some 1/4-inch, galvanized hardware cloth. I'll post a photograph of the modified fender later. :nod

    The next time weather permits, I am going to make another freeway run, and this time I expect the high oil temperature will be much closer to 255 degrees than 279 degrees. :deal

    Spud :beer
    #50
  11. Spud Rider

    Spud Rider Long timer

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    Here are several photographs of my front fender with the wire mesh installed.

    [​IMG]

    [​IMG]

    Weather permitting, I will take a test run down the freeway this afternoon, and note the oil temperatures. :deal

    Airflow over my oil cooler should be greatly increased with the wire mesh installed in my front fender. For comparison, here's a photograph of the drilled fender.

    [​IMG]

    Spud :beer
    #51
  12. elsalvadorklr

    elsalvadorklr southern xr rider

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    hey spud again good stuff,

    I found out big holes work better than smaller holes, the smaller ones act like a mesh screen on the intake of the airfilter, it pretty much just "configures" the air into an area and smooths it out, but for something like this you want buckets of wind which bigger holes or a complete cutout will acheive

    here is my drilled front fender on my 88xr600, its from a crf250x its acerbis its crude but it works man, the holes are big and they are directed right over the head, not onto the cylinder, I took 3 inches off the back of this fender too and so far I have no issues with mud caking the cylinder much...

    [​IMG]

    I do avoid mud though when I can

    My temps after spirited riding(I check right after shutdown and during the middle of rides, I dont have a temo dipsitick yet but want to make one) are great.

    Yesterday after a stint at speed on our highways and back to the house I got 205f for oil temp, perfect. Now I have gotten up to 250f and that was testing right after singeltracking uphill...the big pigs do not like this, at least mine doesnt.

    I also decided against the use of an oversize tank for this reason, it blocked airfllow and the tank itself was to close to the head and the gas would boil on occassion! so I had a new clarke oem replacement tank made and no hot gas issues...

    I believe back in the days scott summers modified his gas tanks and made TUNNELS to channel airflow over and through the head(valve cover) AND back towards the airbox to get fresh air...

    not face to face with the cyilnder as it has fins anyways and gets direct air...

    he also used as we all know the xr250r oil cooler in what I think is the best position and that is up at the headstem where clean air coming right of the fender is the best, just like a wing on an airplane.

    again kudos to you for the write up, you'll get it right Im sure

    christian
    #52
  13. Spud Rider

    Spud Rider Long timer

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    Thanks for the feedback, and the encouragement, Christian. :nod Here's a photograph of the modified fender installed on my XR650L.

    [​IMG]

    I'll take a freeway run as soon as weather permits.

    Spud :wave
    #53
  14. elsalvadorklr

    elsalvadorklr southern xr rider

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    yeah I think thats much better, you want the airflow high and onto the head kind of hitting the tank and then flowing down onto the valve cover...if its just hitting the cylinder it will deflect to the sides, the cylinder has fins so you need to focus on the actual valve cover area....

    let us know!

    p.s. it looks like you have space upwards on the fender to make more holes...I know you want to cool the oil cooler obviously but some holes above to direct air to the valve cover seems like a little help where its needed wont hurt anything!

    cheers
    #54
  15. Spud Rider

    Spud Rider Long timer

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    Indeed, I have lots of room to add more holes, or more wire mesh, above the current mesh. Thanks for your help, Christian. :nod

    Spud :wave
    #55
  16. Spud Rider

    Spud Rider Long timer

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    Looking at the photographs, I now realize the fender can act as a scoop, directing more air to the oil cooler. :deal It will be interesting to compare oil temperatures now, and when the fender was uninstalled. :nod

    Spud :beer
    #56
  17. elsalvadorklr

    elsalvadorklr southern xr rider

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    yup both below and over the fender, the top acts like and airplane wing...thats why the xr250 and xr400 have the coolers installed there, its the perfect place...

    but yeah for now it would be interesting to see the differences

    cheers
    #57
  18. Spud Rider

    Spud Rider Long timer

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    Incidentally, I could easily get another 1/2-inch of clearance between the front wheel and my oil cooler, using my current hardware. Using bent pipe and compression fittings, one could probably mount this oil cooler even higher than that. Therefore, clearance with the front wheel isn't an issue, as long as the front fender is trimmed high enough so the front wheel doesn't grab it, and lock up, long before the wheel would have impacted the oil cooler. :deal

    Spud :beer
    #58
  19. LexLeroy

    LexLeroy Mr. Spoil Sport

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    I used a Ridgid 406 tubing bender and 3/8" stainless .028" wall seamless tubing. The tubing bends easily and is easy to cut w/ a fine-toothed hacksaw. The tubing is about $10 for 4 feet, plus you'll find other uses for the bender down the road. Any excuse to buy more tools....
    #59
  20. Spud Rider

    Spud Rider Long timer

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    Thanks for the tip, Leroy. :D I see the Ridgid 406 tube bender costs about $75, depending on the vendor one selects. :deal I just might get one of these. :nod

    Spud :beer
    #60