fork oil and suspension links

[Ross Lindberg]

As part of my annual maintenance and winter upgrade schedule I figured I would install upgraded screws for the fork oil drain holes. Since I had recently changed fork oil, I figured I would just leave the old oil in and quickly change screws. Just in case I placed a drain pan under the fork leg in case I spilled a few drops of oil. It was a good thing that I did because I dropped the old screw in the pan and fumbled with the new replacement. Sigh. I guess I'll be changing fork oil after all. Based on the recommendation of a friend I have been running Mobil 1 Synthetic ATF in the forks. Weight wise it is similar to 10 weight fork oil, so the ride isn't quite as plush as with 7 wt, but the fork action is soooooo smooooth due to the slipperiness of the synthetic oil that I have been very pleased. I head for my secret stash of all things motorcycle and discover that I don't have enough ATF to do the change; lots of Bel-Ray 7 wt, but no ATF. It's Sunday afternoon and there is no one open locally where I can get Mobil 1 ATF, so I guess I'm switching back to 7 weight oil. Jeff Saline and I have a long running, friendly disagreement about changing fork oil. Jeff's opinion is that the forks should be completely disassembled, given a proper cleaning, then reassembled and filled with fresh oil. While I agree that it's probably the best way to do the service, it's an awful lot of work when the oil will likely be dirty again in short order. My argument has been that frequent flushing and changing of the oil should eventually clean out the forks providing that the wear of the moving parts stabilizes with time and your fork seals are intact. The first time I changed fork oil I was amazed at the amount of aluminum debris suspended in the oil due to break in wear. Would my theory prove true? Only time and miles would tell. Inspecting the oil drained from the right fork leg was telling. 11,640 miles on the bike with 3 changes along the way. The ATF was practically as clean as the day it was poured in. Score one for my logic! Looks like I will be able to give Jeff a little ribbing after all! I'm pretty pleased with myself until I drain the oil from the left leg. Ick. Almost as dirty as ever. What's the deal here? After some thought I have narrowed it down to a couple of theories. First, the left leg of the forks in under more stress and movement due to the brake disk being on that side. Perhaps the forces generated by braking are stressing that leg more resulting in more wear to the internals. Second theory; perhaps there is something amiss inside the left tube. This is where Jeff's method would prove very helpful as you would get a first-hand look at wear patterns and the condition of the internal parts instead of just guessing. As for me, I decide to not worry about it and fill the forks with fresh oil so it's ready for spring. I'll be leaving for California in a couple of days and done have time to worry anyway. So, based on this experience, who's method is the right one? Well I'd have to say we both are, or perhaps a combination of both. My thinking is if you pile on a bunch of miles, a yearly dismantling and inspection of the fork internals are a great idea. At least you know for sure what's going on in there. If you don't put on that many miles, or are not so mechanically inclined, at least change the fork oil and don't be afraid to change it often. It's a simple job that can be done in about half an hour once you get the hang of it, and your forks will thank you. Ross Lindberg Fertile, MN [Non-text portions of this message have been removed]

[Larry]

As you say, it depends on experience and the tool inventory a guy has. Dis-assembling a damping tube fork may seem pretty routine to some but to others it may be a formula for leaking seals or stiction. FYI. I just drained the forks on my 08 after 7K miles and there was not a speck of aluminum in the oil. Amazing. So I put it back in and just set the oil level. It uses Kayaba 10 wt. so when I do change it, I will try synthetic AT. Sounds like a great idea. Thx, Larry.

--- In DSN_KLR650@yahoogroups.com, "Ross Lindberg" wrote: >> So, based on this experience, who's method is the right one? Well I'd have > to say we both are, or perhaps a combination of both. My thinking is if you > pile on a bunch of miles, a yearly dismantling and inspection of the fork > internals are a great idea. At least you know for sure what's going on in > there. If you don't put on that many miles, or are not so mechanically > inclined, at least change the fork oil and don't be afraid to change it > often.

[Jeff Saline]

Listers, Thought maybe the below sites might be of interest as you gather information about suspension systems and fork oil. I don't know anything about the information other than it's on the web. I suppose that means it's true and correct. : ) Suspension information and other subjects too. http://www.peterverdonedesigns.com/index2.htm Suspension fluid comparisons http://www.pvdwiki.com/index.php?title=Suspension_Fluid Best, Jeff Saline ABC # 4412 South Dakota Airmarshal Airheads Beemer Club www.airheads.org The Beautiful Black Hills of South Dakota 75 R90/6, 03 KLR650, 79 R100RT . ____________________________________________________________ Shed some light on the subject. Click here for great prices on light bulbs. http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTGU29tsdqoXAspA1WlexsXJKoGEZ1T968D7ZeMzBtPkN6ynuBxXIs/