Fork oil changing-anyone tried this?

[Further]

OK, 14 years with BMW K-bikes spoiled me in the fork oil change department I guess. But I don't understand why every manufacturer doesn't just install little set-screw fork bleeders at the end of the forks along with fork caps that have a small refill plug? Is that too much to ask?

It made life soooo simple for me for the last 14 years. Every year drain and flush and refill the forks ... 20 minutes max. And no lifting the front end.

Is this just a built-in service dept. money generator?

So I'm thinkin' a good machinist could tap 2 holes in the bottom of the forks to accept a BMW set-screw w/o-ring. Problem is filling from the top. Haven't taken the forks off yet. Can those compression adjustment knobs on the fork caps be removed to refill from the top. On the BMWs you refill according to CC's you don't do it by measuring the distance the fluid level is from the top.

Is this a crazy idea?

Chris

 

[fhaze]

sounds like a great idea to me, it sure beats my current method of flipping the bike upside down, like you used to do to your pedal bike when you were a kid.

 

[v65]

OK, 14 years with BMW K-bikes ...Is this just a built-in service dept. money generator?

No help with the forks, but I find that funny!

 

[HaulinAshe]

Two things come to mind.

1. There is a great benefit to the disassembly process because of being able to agitate the fluid in both the inner cartridge and the outer tube sections before draining. When I service forks, I do much more than simply exchange the fluid. I do a lot of flushing of contaminants and visual inspection of bushings, seals etc. However, I doubt most dealerships take the time to do what I do personally for myself.

You could combat this concern by changing fluid more often and relying on the more frequent changes to keep the inner cartridge fresh and clean.

2. Getting the fluid level right. How much you put in is not nearly as important as getting both sides exactly the same height. It's hard to tell a 5mm difference in height when both are matched. But you sure as hell can tell when one fork is 5mm different from the other. Substantial differences in fluid height can quickly show up in tire wear as well as handling, bar vibrations etc.

So I guess I'm saying "Yep, you could tap them puppies and change fluid without disassembly of the forks." But personally, I'd take them down once a year anyway.

I did just have one last thought (A mind is a terribly slow thing on a Redneck!)...

If you tapped both the top cap and the lower tube casting, you could possibly use a suction tube to extract the fluid to an exact level. One obvious caveat would be anyone NOT using bone stock springs would have to determine their own, personal fluid height to target. Because the fluid height measurements are based on how much fluid the stock springs displace, and are specified WITHOUT a spring installed. You would have to do the first service by disassembly, then assemble and accurately measure the fluid height for future reference and servicing without disassembly.

 

[Further]

I think I understand what you're saying about determining fluid level. What if you disassembled and carefully drained all the fluid as best you could. Measured that quantity. Divided by half. Then added in say 5 cc's to account for what couldn't be drained, and used that figure as your base starting point fluid amount for each leg? Seems like that would get you in the ballpark and you could add a little in the future if it wasn't perfect.

Also, I agree that draining isn't as effective as disassembly. If I would ever adopt this as a practice I would certainly do a good flushing with some sacrificial fluid first, then refill. And probably do a full disassemble every 3rd time maybe.

I'm gonna' hafta ruminate on this one a while.

 

[Bustanut joker]

You still have to remove the top cap right? So why not measure as always and fill to the level prior to the drain off. Plus once ya did it ya might just put it on paper. Easy peesey.

Yas owe me a twelve.

:jester:

 

[twowheelnut]

It takes all of 30 minutes to yank the forks. Therapy, it is.

 

[radman]

It takes all of 30 minutes to yank the forks. Therapy, it is.

That long, eh? Amateur..........

 

[Warchild]

I think I understand what you're saying about determining fluid level. What if you disassembled and carefully drained all the fluid as best you could. Measured that quantity. Divided by half. Then added in say 5 cc's to account for what couldn't be drained, and used that figure as your base starting point fluid amount for each leg?

I would not approach this task in this manner.

The preferred way to determine the factory-set air gap in your forks is to remove them off the bike (which you must do anyway to flush/refill), remove the fork cap and simply measure the distance from the fluid level to the top of the fork (using whatever method tickles your fancy: a ruler, a small wooden dowel, a pipe cleaner, etc).

While removing the forks might seem like an ***-pain when you are used to fork drain plugs, as TWN correctly observes, it is therapy. And affords you the opportunity to inspect the surrounding area for any developing problems before they become major issues.

 

[twowheelnut]

That long, eh? Amateur..........

Hey, that includes a few minutes to watch the lady in the shower across the way.

 

[Rayzor61]

untighten the compression cap before removing the forks; this way you don't have to put the fork tubes in a big "fork eating" vice and possibly dent or marr them. my 2 cents.........

 

[panayoti]

seriously how long does it take ? The local dealer wants 4 bills to do the work.

 

[cadman]

untighten the compression cap before removing the forks; this way you don't have to put the fork tubes in a big "fork eating" vice and possibly dent or marr them. my 2 cents.........

thanks for the tip Rayzor61!

this forum ROCKS!

cadman

 

[Sherman]

I think a guy with some wrench experience could do it in 3 to 4 hours first time out. A good mechanic less than 2 hours.

I could waste a day at it, but that would include a few hours on the forum and coffee and lunch and a trip to the local Yamaha shop.

 

[GPRIDER]

seriously how long does it take ? The local dealer wants 4 bills to do the work.

Holy Crap! I'm glad I've learned to do most of these things myself. I think I'd do other peoples fork oil changes for $400. That's some pretty good profits.

 

[FatNakedGuy]

Hey Tim, I remember that therapy at Armands house a few years ago. I was puckerin' hard on your behalf bro!