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Thread: Fork oil

  1. #1
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    Fork oil

    Hello all round, I would like to change my fork oil on my 1980 R100RT. After checking the specs I have looked for Aeroshell 4 but can only buy a case, so Plan B what else shall I use? all advice gratefully received, Heed
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  2. #2
    Administrator 20774's Avatar
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    Snowbum has plenty to read here:

    http://bmwmotorcycletech.info/viscosity.htm

    Me, I used BMW's 7.5w fork oil.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
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    Bel-Ray

    I have used Bel-Ray - used to be the fork oil standard.

    Can be had at virtually any mc dealer.

    Change often!

  4. #4
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    fork oil

    I have the same year, though different looking forks. A&S Motorsports recommended BMW Motorrand Grade 7.5.
    SnowBum is an amazing source of information. Unfortunately I don't always have the band width to follow his writings. Wish I did.

  5. #5
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    Spectro here
    "If I had my life to live over, I'd dare to make more mistakes next time...I'd relax,I'd limber up... I would take fewer things seriously...take more chances... take more trips...climb more mountains...swim more rivers...eat more ice cream." Jorge Luis Borges at age 85.

  6. #6
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    Brand is pretty much irrelevant (as it is with nearly all lubricants). 7.5W seems to be most popular for avg weight folks. 5w if you're slight, 10w if you're robust.
    Ride Safe, Ride Lots

  7. #7
    Administrator 20774's Avatar
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    Unfortunately, 5w by one brand won't feel like the same 5w by another brand. This is something that a person has to try out and see what works. Once you found what you like, stick with it.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #8
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    I replace the PJ1 7.5 wt fork oil in my '78 with Mercon V automatic transmission fluid. The forks feel about the same to me. I made the switch because some extra ATF was available and I have another lower fork to swap out for a dual brake conversion. Also, my '77 Clymers manual describes using hydraulic fluid in the forks and ATF is hydraulic fluid. The viscosity looked about right from the Mercon V specifications and the forks feel OK to me. Fork feel is somewhat subjective so YMMV.
    Stan

    AH# 13238

  9. #9
    Bluenoser
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    Many have used AFT with no issues, I have and added about an ounce of seal swell to the mix to help with the fork seals.

    You can adjust the weight from 5- 10 to suit the type of riding you do. The 7.5 is a base line and for the weight and type of bike that should be fine. The type of valving in the fork really determines what fork weight oil works best ( in the manufactures eyes ) but that doesn't apply if you fall outside the base line ( type & weight of riding etc ). Some want a little softer front end and some want a firmer front end. There are many manufacturers that make fork oil and any of the popular brands will work fine. The bike won't know the difference, as long as its fork oil.

    Don't get too hung up on brand names. If its fork oil it will work.
    1971 R50/5 SWB with R75/6 drivetrain
    2013 DL650

  10. #10
    Registered User dwyandell's Avatar
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    Spectro or BelRay usually for me, at present 5w Spectro in my ST but I discovered that Kubota SuperUDT hydraulic fluid seems to give the right feel in the R100 rig.
    Experiment with a few different things to find what feels right to you. . . .including different brands, varying the weight AND the volume (a bit).
    Dave in Vermont
    '84 R80ST
    '81 R100 hack

  11. #11
    Registered User jad01's Avatar
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    After rebuilding my forks, I experimented a bit with Bel Ray and Maxima (and maybe PJ1?). I also played around with the weights (5, 7, and 10wt). Through my very unscientific process, I finally settled on Maxima 7 wt fork fluid. The Maxima fork fluid does seem to reduce stiction over the other oils I tried. The 7 wt seems to match my springs (Progressive Suspension) nicely. I liked the Bel Ray 5 wt also, but it seemed like the forks were a little underdamped for the springs I had installed- it might have worked with the stock springs, though.

    http://www.maximausa.com/shopping/in...products_id=44
    Jim
    '78 R80/7 and '84 R100RS (Blues Brothers), '86 K75C (Icy Hot)
    '90 and '93 Mazda Miatas (Jelly Bean and Red Hot), '02 325ci (Blue Streak)
    '96 Giant Upland (big Kendas & freshly greased bearings!)

  12. #12
    got, got, got no time... rguy's Avatar
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    I've experimented with PJ1 and Bel Ray. Went back to the standard 7.5 BMW oil, it seemed to work best for me. At about $7 a quart it is probably cheaper than the others! Oh, by the way, the back of the bottle says it was formulated by Spectro. Works for me, I'm a happy camper, errr, I mean rider.
    Neal - '09 R1200GS / '81 R65
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    Be the person that your dog thinks you are.

  13. #13
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    video?

    Does anyone know if there is a video on changing for oil on a /6 or /7. Not one doing a rebuild, just a fork oil change.

  14. #14
    Registered User dmftoy1's Avatar
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    Fork oil

    On a slash six isn't it just a matter of taking off the cap and using the hex key/ socket trick? If I remember right when you loosen the lock nut you can push the hex doodad back up breaking the seal and the oil drains out.

  15. #15
    jeepinbanditrider
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    I've had good luck on my F800 running Mobil 1 ATF. Feels great but the stuff I took out was two different colors and probably two different weights. When I first got the bike it blew a fork seal and the dealer only replaced the fluid in one leg when I took it in to get it fixed for free.

    Quote Originally Posted by Dmftoy1 View Post
    On a slash six isn't it just a matter of taking off the cap and using the hex key/ socket trick? If I remember right when you loosen the lock nut you can push the hex doodad back up breaking the seal and the oil drains out.

    If it's a damper rod fork the tail end of a spark plug socket should fit it perfectly into the top of the damper rod allowing you to remove the allen bolt in the bottom easily.

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