Motorcycle Racing Forum

Racing Discussion => Racing Discussion => Topic started by: ssduc750 on May 13, 2006, 12:17:07 PM

Title: Changing Fork Oil
Post by: ssduc750 on May 13, 2006, 12:17:07 PM
In general, is it possible to just change the Fork Oil on a bike without having to tear out all the internals?  I realize the fork has to be taken out of the triple clamps as there is no way to get the oil out (is there?) without doing that. Thanks for any help you can offer.
Title: Re: Changing Fork Oil
Post by: Jeff on May 13, 2006, 12:40:07 PM
Well, you can always hang the bike upside down from the rafters...

If you're changing the oil, you're gonna want to clean any crap out of the forks too and possibly change the seals.  Don't shortcut stuff when you're doing the work.

I have the easiest method around.  Remove forks.  Hand to Suspension-Ed.  Wait a few.  Reinstall forks. 
Title: Re: Changing Fork Oil
Post by: cardzilla on May 13, 2006, 02:49:54 PM
Modern forks are very complicated, especially inside the cartridges.  The tiniest bit of debris can completely screw your damping rates.  Most of the crap that is in the oil is in the bottom, this crap is the reason you're changing the oil in the first place.  You should completely disassemble the forks and replace any necessary seals or bushings.

If you want to do a rig job, take the forks off and leave them upside down overnight.  Then take the cap off and drain... be sure to pump the cartridge out as best you can (difficult with the spring in).  This will help to get particles out, but it's a poor alternative to doing it right.

Also remember to bleed the air out when you're done.  Take your time, and if you don't know this step you shouldn't be touching the forks for sure.
Title: Re: Changing Fork Oil
Post by: K3 Chris Onwiler on May 14, 2006, 12:22:45 AM
Ya know....  Your suspension provider will probably do a fork service for a hundred bucks or so.  Good for you, good for him, good for your bike.... 
I'm all about saving a buck, but your forks aren't the place. If you can't do the job right yourself, don't half-ass it.
Title: Re: Changing Fork Oil
Post by: 251am on May 14, 2006, 07:55:48 AM
Quote from: Jeff on May 13, 2006, 12:40:07 PM

Don't shortcut stuff when you're doing the work.

I have the easiest method around.  Remove forks.  Hand to Suspension-Ed.  Wait a few.  Reinstall forks. 


+1 Ed's the man. You can either ship to him or MAYBE have it done at the track. He rebuilt my Showas last weekend at BHF and I watched/helped with the entire process over a 9 hour period. LOTS of folks approached for help in that time period. These Showas now rock the free CCS world! Thanks again Ed. (PS-Ed enjoys Guinness)
Title: Re: Changing Fork Oil
Post by: DAmico on May 17, 2006, 12:57:45 AM
You need to disassemble the forks to do the job correctly, for the reasons Mr. Cardzilla said. To save time and money you could always bring your forks to Badger Motorsports in Menomonee Falls, Wi and we can do the job for well under a hundred dollars. I don't want to mention names but many fast guys take thier stuff to Badger for routine stuff. If you want valving and mods Trackside is the ONLY guy, but for upkeep Badger can take care of you.

Badger Motorsports
262-250-1010
Main street in Menomonee Falls, Wi
Title: Re: Changing Fork Oil
Post by: chainsaw on May 17, 2006, 07:34:33 AM
Take em to Jason at Badger for routine maintenance!  He's fast, thorough, and knows his stuff...well worth the money, especially if you don't have the right tools.
Title: Re: Changing Fork Oil
Post by: Super Dave on May 17, 2006, 08:54:14 AM
Quote from: ssduc750 on May 13, 2006, 12:17:07 PM
In general, is it possible to just change the Fork Oil on a bike without having to tear out all the internals?  I realize the fork has to be taken out of the triple clamps as there is no way to get the oil out (is there?) without doing that. Thanks for any help you can offer.

Does your Duc have cartridge forks?  Where do you live?
Title: Re: Changing Fork Oil
Post by: H-man on May 17, 2006, 12:53:43 PM
So.... how do you know when to change your fork oil?    Once a season?  After X miles?  When you feel _____ when cornering/riding?

Uh... I'm asking for a friend :rollseyes:
Title: Re: Changing Fork Oil
Post by: Super Dave on May 17, 2006, 02:29:15 PM
It's not an oil that's in a place where it's under the heat of combustion.  So, it won't wear down like engine oil.

Suspension does have some generation of heat through friction, but not alot of heat.

Fresher is faster, the saying goes, but I honestly I haven't had my forks open many times.  I know another very fast guy that doesn't get his suspension components serviced often at all.

The oil goes through various orifices that beat up the oil and change its ability to be completely consistent in dampening.  Additionally, it can pick up metal flakes that are not filtered by any means.

How often?  Your mileage may vary.  I change the oil in my car every 5000 to 7500 miles.  Others do it religiously at 3000.
Title: Re: Changing Fork Oil
Post by: ssduc750 on May 17, 2006, 06:36:44 PM
Showa Non adjustable. Not exactly the #1 choice for racing. That's why I'm looking at my options to beef them up, so to speak. Can't convince my Wife that I need some new Ohlins. I'm in South Eastern Wisconsin. I was the one at BHF with the screwed up knee asking you where the Race Director was and if you had seen Alexa yet. ANY help will be apperciated. Thanks.
Title: Re: Changing Fork Oil
Post by: Super Dave on May 17, 2006, 06:55:21 PM
Ah, ok, I'm there...

Before all the current forks there were simpler forks.  We raced with non cartridge forks for a long time.  My new R6 will be the first bike I've owned or raced with USD forks.

I've done simple oil changes without disassembling forks.  I changed the weight of my fork oil on my R6 without disassembling them. 

Biggest recommendation I would have would be to measure the height of the oil in a state that you can consistently measure it.  Preferably, you'd do it with the springs out and you've moved some oil through the fork by cycling the tube and the cartridge stuff up and down.

Like others have said, I like to have my suspension work done by someone I trust.  I use http://4and6.com for my stuff.  We installed my Hyperpro shock in early 2003 and we haven't done anything to it.  Forks have had very little done. 

Do you have a specific reason why you're looking only at the fork oil?
Title: Re: Changing Fork Oil
Post by: ssduc750 on May 17, 2006, 07:32:42 PM
No, not really. If a valve kit is available, I'll go that route too. Just looking for something, anything to stiffen the front up a little. I have no problem letting someone else do the work. I have neither the time nor the experience. That's why I figured I'd try the oilr route first just to see if it would heip, then go from there.
Title: Re: Changing Fork Oil
Post by: Spooner on May 17, 2006, 08:13:08 PM
I tend to change the oil in my forks every couple race weekends.  The cartridge forks are pretty hard on the oil and it generally looks pretty nasty every time I change it.  The whole process is pretty easy really-I can have the forks pulled off the bike, change the oil, and back on in about an hour.
Title: Re: Changing Fork Oil
Post by: Super Dave on May 18, 2006, 08:25:28 AM
Quote from: ssduc750 on May 17, 2006, 07:32:42 PM
I'll go that route too. Just looking for something, anything to stiffen the front up a little.

Stiffen the front?  Well, maybe you're going the wrong route.  Rather farming an oil change, you should look into checking what the correct spring rate would be for your bike with your weight.  If the dampening overcomes the spring rate, you'll be in trouble.  The correct spring rate will allow the front portion of your bike to maintain some of it's geometry under race conditions.  Same goes for the rear shock too...correct spring rate is very, very important.  And the rear affects the front.
Title: Re: Changing Fork Oil
Post by: EM JAY on May 18, 2006, 11:53:43 AM
Quote from: Super Dave on May 18, 2006, 08:25:28 AM
  And the rear affects the front.

.......like how most females with more "front" lack in the "rear" ?

Title: Re: Changing Fork Oil
Post by: Super Dave on May 18, 2006, 12:00:32 PM
(https://www.ccsforum.com/proxy.php?request=http%3A%2F%2Fwww.theweeklygiggle.com%2Fimages%2Fbaby_got_back.jpg&hash=1056df4d4f67563539eab2fcc8b6bd34df8187e9)

I think some get extra...
Title: Re: Changing Fork Oil
Post by: EM JAY on May 18, 2006, 12:25:13 PM
 LOL!!!  Try settin the sag on that!!!
Title: Re: Changing Fork Oil
Post by: cardzilla on May 18, 2006, 05:22:45 PM
Quote from: EM JAY on May 18, 2006, 12:25:13 PM
LOL!!!  Try settin the sag on that!!!

I think you're gonna need a whole hell of a lot of rebound out back.