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Fork oil

Discussion in 'The Garage' started by patrickp, Nov 12, 2009.

  1. patrickp

    patrickp XS650 Member

    It may sound like a trivial question but I'm doing a nut and bolt restoration of my 1975 XS650B which is nearly back on the road. Went to the motorfactors today to buy 10/30 fork oil but was told it was unavailable. Can anybody recommend what weight fork oil I should use. The Haynes manual says 10/30 as does the original Yamaha supplementary service manual.

    Any advice would be greatly appreciated.

    I'll post a photo when the bike is finished. Can't wait!!!
  2. inxs

    inxs xx

    - try mixing your own with 10w and 30w
    - XS-B has i think 175ml oil so say 140/10w and 35/30w
  3. "You can use 10, 15, 20 or 30 weight motor oil in the front forks, experiment with weights for the feel you like." http://www.650central.com/tech/tips.htm

    I'd just use 10w and see how you like it. I've also read about people using synthetic ATF in their forks. They say it's pretty much like 10w fork oil but keeps a more consistent viscosity with temperature changes.
  4. 5twins

    5twins XS650 Guru Top Contributor

    Yes, I'm pretty sure that 10W30 spec refers to just plain motor oil. Back in the early to mid '70s, real fork oil wasn't as readily available so many manufacturers speced motor oil for their forks. A 10W real fork oil would probably be fine. That's what the later forks call for. If you don't like it, try something heavier.
  5. crash

    crash XS650 Junkie

    we run synthetic atf in all of our forks,havent had any problems and its a good ride:bike:
    Last edited: Nov 13, 2009
  6. 10/30 is a motor oil is it not ??. I use specific fork oil in my bikes.
  7. bsatrinor

    bsatrinor XS650 New Member

    i use 10w/40 rotela or delvac---same as i use in the motor-----the best truck oil
  8. Welcome to the site bsatrinor!
  9. inxs

    inxs xx

    - bsatrinor...nice pedigree...expensive hobby these days...servus
  10. crash

    crash XS650 Junkie

    welcome to the forum
  11. Gordon

    Gordon XS650 Junkie

    I use the Bel-Ray fork oil from the local mc dealer.$3 a quart.It come's in a variaty of weight's, but I stayed with 10w, work's good for me. Hello Twin's, glad to hear you again.
  12. Skip

    Skip XS 650 Screwturner

    I use 30 weight oil in my forks.
    I like the feel it gives the front and the bike does not "nose dive" if you got to get on the brakes quick!
  13. gentlemanjim

    gentlemanjim More Wrenchin than Ridin

    I believe the manual was referring to the range of appropriate oil as 10, 20, 30. your choice. Fork oil and ATF synthetic or mineral have sealswell agents in them that keep the sealssoft pliable and help prevent leaks. Motor oil does not. Use a fork oil or ATF 10 is a middle of the raod and is quite universally accepted.
  14. tx650

    tx650 XS650 Enthusiast

    I have used hydraulic oil having used hydraulic machines.
    I suppose it's like the good oil question?
    What is the best oil?
    Does'nt it all come from the same hole in the ground?
    The scariest thing to find in a new container of oil is contaminates in the bottom????
    gggGary likes this.
  15. hotrdd

    hotrdd XS650 Junkie

    I'm trying to pick an ”off the shelf" fork oil that I can get from my local auto parts store. Is there a guide on what is acceptable? Should I pick different weight oil based on my weight? Also do I need to be concerned about the oil affecting my seals?
  16. gentlemanjim

    gentlemanjim More Wrenchin than Ridin

    I use power steering stop leak fluid. Seal swell is an important component of the fork oil. Do not use motor oil. IF you wanst the best advice buy a true fork oil it has seal swell and you have a choce in viscosity 15wt is a good middle of the road choice. It has nothing to do with your body weight.

  17. oldbiker

    oldbiker oldbiker

    hi i use usa,,,, delray oil....10wt/// works great and easy to get regards oldbiker
  18. This thrad just reminded me that Ive never replaced my fork oil! On the to do list for tomorrow!
  19. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    I use 15W40 diesel oil in the forks.......................been in there the last 4 years and works great. Much better front end feel than the 10W I used before. I use 203 cc or 7 oz per fork.
  20. 5twins

    5twins XS650 Guru Top Contributor

    That's probably because it's thicker. Yamaha speced 20wt in '77 but then changed to 10wt after that. It may be a little too thin. They also beveled the holes on the damper rods at least up to '78. According to my engineer buddy, that increases flow through the holes. So what does all this mean? I think I'll try a 15wt real fork oil.

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