How to drain F650GS Fork oil? - BMW F800 Riders Forum & Registry



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  1. #1

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    This may be a stupid question but how do you change the fork oil since there are no drain bolts at the bottom of the legs on the F650GS. I hope I don't have to drop the sliders just to change to a different oil weight. I'm thinking maybe take the fork out of the triple clamps and turn it upside down might be the easiest. Anyone know an easier way?
    Also, has anyone confirmed if the old F650 fork springs and fork kits (emulators) will fit the new twin? They appear to be the same size. Doesn't seem to be anything else available in the US yet.
    Thanks for any help. Gary

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  3. #2
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    I just changed the oil in my Suzuki SV650. The official way is to remove the fork tubes, turn them over and drain the oil. It was too much work for me. Instead I bought a suction pump from an auto accessory catalog that is used to drain oil from auto sumps. (I have no idea why you would need to do that when every auto sump that I have ever seen has a drain plug.) Anyway, I took off the fork caps, removed the springs, pushed the fork sliders all the way up by placing blocks under the front wheel, after first lifting the bike using a floor jack under the engine, and sucked the oil out of the forks. I then poured new oil into the forks to the level specified in the service manual (about 6" measured from the top of the oil to the top of the tube), dropped the wheel, replaced the springs and fork caps. Job done. It only took about 30 minutes. I might have left a little old oil in the bottom of the tubes, but I figure I got out most of it and anyway, the oil that came out looked like new. I might add that the mechanic at my Suzuki dealer recommends replacing the fork oil every 15K miles. I changed my oil at 6K miles because it was so easy, whereas if I had to do it the "official" way I would have waited much longer. I might add that the forks on my SV650 seem to be very similar to the ones on my F650GS, except the GS forks have longer travel.

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  5. #3

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    Richard, I like your idea and I have one of those pumps laying around somewhere. I'll just note the level of oil in the tube before I pump it out since I don't have a manual. Thanks, Gary.

  6. #4
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    For the F650GS the manual says:


    Fork oil, capacity per fork leg: 530 ml
    Hydraulic fluid SAE 7.5
    Level of fork oil in fork leg (air chamber) Forks fully compressed, spring removed, spacer installed: 100 mm


    In terms of measuring the level the way the specification is written seems a bit odd to me... "spring removed, spacer installed"

    The diagram shows the spacer tube sitting on on top of the spring .... so you take the cap off, pull the spacer out, pull the spring out, then drop the spacer back in ... ???

    Measure/adjust the level then pull the spacer back OUT so you can put the spring back where it belongs???

    Am I missing something here?
    Blue 2009 F650GS - H-B crash bars, TT luggage rack, Pelican top case, BMW Vario Panniers & bash plate, 20mm handlebar risers, LED voltmeter, Sargent seat, MudSling, a few other trinkets ... I may be just about at the end of the farkle train  

  7. #5
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    I think whoever wrote those instructions in the manual is nuts (or misinformed - maybe the same guy that thinks the new G650GS is powered by a boxer engine). If you replace the spacer in the fork without the springs, it will fall to the bottom of the fork where it will be very difficult to remove. My recommendation would be to keep the spacers and springs out of the forks, pour 530ml of oil in to the forks and adjust the level to 100mm as measured between the top of the oil level to the top of the fork tube. Just be sure that the forks remain fully compressed while you are measuring the oil level.

    P.S. several specialty M/C tool companies sell devices to adjust the fork oil. They use a stiff tube attached to a syringe and a plug that sits over the top of the fork tube. You set the length of the tube to the required measurement, overfill the oil level slightly and suck the excess oil out of the forks to get the correct level. Needless to say you could make one of these tools yourself for a few bucks. Or you could just use a ruler to measure the oil level - this is not brain surgery. No doubt BMW has a special $100 tool that attaches to the shop computer to take the official measurement and report back to the factory warranty department goons. :p

  8. #6
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    For ONLY $100??? You're kidding right... that tool has to be worth at least $475???

    Yeah... I don't get it on the spacers, and agree ... I would not put them in either .... on the other hand if that's what they REALLY did in Germany you will end up with a bit too much oil in the forks ... by the volume amt. that the spacer would have displaced.... sigh..........

    but I did copy-and-paste the text right out of the DVD-manual ...

    I'm the kinda guy that would like a job as the technical proof reader ....
    Give me a bike a set of the "special" tools and a month with the manual and I'll get the damn thing right!

    Jim
    Blue 2009 F650GS - H-B crash bars, TT luggage rack, Pelican top case, BMW Vario Panniers & bash plate, 20mm handlebar risers, LED voltmeter, Sargent seat, MudSling, a few other trinkets ... I may be just about at the end of the farkle train  

  9. #7
    Calgary, AB, Canada blackie is offline Volunteer Moderator - GS, HoW
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    Motorcycle
    '08 F650GS (Twin)
    Great idea on the suction thingy!
    2008 Iceberg Blue F650GS  

  10. #8

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    Dumping the oil, rinsing with solvent, rinsing again with transmission fluid is preferred. You'll be amazed by the crap that settles to the bottom and will come out. My F650 arrives in January. The forks need work. What's the current opinion? more oil, but lower viscosity? That worked wonders on my 650 V Strom...similar forks. Any thoughts on a longer spring preload spacer?

  11. #9
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    All I can say is that the suspension on my F650GS works perfectly for my light weight (145 pounds). I have the rear shock set to minimum preload and dampening. I have a plastic tie around the forks of my SV650 and also my F650 and the tie on the SV moves almost up to the lower triple clamp, whereas the tie on the F650 is about 4" from the lower triple clamp. I ride and brake both bikes the same, although I will admit that the SV brakes harder than the F. Both the fork preload and dampening seem perfect for my weight and riding. I mostly ride on mountain backroads at around 50-60 mph and corner about 50% above the recommended speed on the corner warning signs with no pucker factor. I can double the warning sign speed in a pinch, but I get real worried about unseen rocks, branches or U-turning cars that might be in my path and that makes the higher speeds no fun. The bike will do it though.

  12. #10
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    Richard:

    On the rear damping adjustment: is there a "stop" on the adjusting screw so that you know when you are all the way out....

    Or does the screw just come out in your hand? ;/

    Thanks,
    Jim
    Blue 2009 F650GS - H-B crash bars, TT luggage rack, Pelican top case, BMW Vario Panniers & bash plate, 20mm handlebar risers, LED voltmeter, Sargent seat, MudSling, a few other trinkets ... I may be just about at the end of the farkle train  

  13. #11
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    The screw does not come out in your hand! There is a definite stop. However, the shock on the F650GS does not have detents. You can turn the rebound dial clockwise to firm up the damping and counterclockwise to reduce rebound damping until the screw stops turning. There is no "clicking" like on some other shocks. You have to count the turns from one end or the other to determine where the damping adjustment is set. The convention is to count the number of turns from full hard to describe the damping setting.

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  15. #12
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    Thanks!
    On mine, from the dealer, it was about 1.5 turns out.
    I am about 180lbs and have it at 2.0 turns now but did not want to back off further for fear of having the screw come out in my hand and then watching the fluid run down the frame ....

    I'll be more aggressive with my messing around now!

    Jim
    Blue 2009 F650GS - H-B crash bars, TT luggage rack, Pelican top case, BMW Vario Panniers & bash plate, 20mm handlebar risers, LED voltmeter, Sargent seat, MudSling, a few other trinkets ... I may be just about at the end of the farkle train  

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