Ducati Monster Forum

Moto Board => Tech => Topic started by: ian48th on July 10, 2010, 09:02:11 AM

Title: fork stiction and front axle
Post by: ian48th on July 10, 2010, 09:02:11 AM
I recently measured the static sag on my 2000 M900Sie (Showa forks) and found the stiction range to be about 15mm.  According to this article - http://www.ehow.com/how_4602262_setup-suspension-sportbike-motorcycle.html (http://www.ehow.com/how_4602262_setup-suspension-sportbike-motorcycle.html) - anything more than 10mm is a red flag.  So...

1) Should I check the torque of the front axle nut?  I don't have a socket that fits it.  I measured it and thought it was 27mm, but bought one and it's too small.

2) What is the DMF-accepted stiction range?

3) Anything else, short of rebuilding the forks?

Thanks.
Title: Re: fork stiction and front axle
Post by: BK_856er on July 10, 2010, 10:53:15 AM
I posted this link in another thread recently.  It might help reduce your stiction, and it's free to try - worth a read.  You'll need a torque wrench and the correct sockets/bits, plus a means to raise the front.  Might be a good time to replace the fork oil while you're at it.

http://motocd.com/Tech/Front%20Suspension%20and%20Wheel%20Installation.pdf (http://motocd.com/Tech/Front%20Suspension%20and%20Wheel%20Installation.pdf)

BK
Title: Re: fork stiction and front axle
Post by: ian48th on July 10, 2010, 12:12:16 PM
Thanks for the link to the PDF.  It says the nut is a 28mm.  Sears had 27 and 30, so I'll check elsewhere for that. 

I began to notice poorer handling in the front after my latest tires were installed and I assumed it was the tires, but now think they may not have tightened up the axle and pinch bolts quite right.

I don't have a front stand, so I'll have to look into that.
Title: Re: fork stiction and front axle
Post by: Speeddog on July 10, 2010, 03:10:33 PM
Loosen the axle pinch bolts on the right side fork bottom, that should be the side opposite the nut.

Aggressively bounce the fork through as much of the travel as you can.

Retighten the pinch bolts, but don't go real tight...
Title: Re: fork stiction and front axle
Post by: ian48th on July 10, 2010, 04:10:09 PM
Quote from: Speeddog on July 10, 2010, 03:10:33 PM
Loosen the axle pinch bolts on the right side fork bottom, that should be the side opposite the nut.

Aggressively bounce the fork through as much of the travel as you can.

Retighten the pinch bolts, but don't go real tight...

Since I am wanting to check the torque on the axle nut, would I loosen the axle nut, then tighten the axle nut to correct torque spec, then loosen pinch bolts, bounce forks, and retighten pinch bolts?
Title: Re: fork stiction and front axle
Post by: ducpainter on July 10, 2010, 04:13:45 PM
Quote from: ian48th on July 10, 2010, 04:10:09 PM
Since I am wanting to check the torque on the axle nut, would I loosen the axle nut, then tighten the axle nut to correct torque spec, then loosen pinch bolts, bounce forks, and retighten pinch bolts?
The pinch bolts on the left side will allow you to torque the nut.

As long as you tighten the pinch bolts on the right side last you'll be good.
Title: Re: fork stiction and front axle
Post by: ian48th on July 11, 2010, 11:09:13 AM
Thanks for the advice.  After loosening and retightening, the stiction range is about 13mm as opposed to 15mm. 

Is there a recommended replacement interval for the fork seals?  My bike is ten years old with 22,000 miles.
Title: Re: fork stiction and front axle
Post by: coarsegoldkid on July 11, 2010, 02:15:36 PM
Fork seal grease may help you knock off a few more mm of stiction.  Pull the dust covers down exposing the seals.  Smear the grease on and reset the dust covers.  Bounce the forks through their travel.  Wipe off the excess and ride it.  See if that helps.
Title: Re: fork stiction and front axle
Post by: ducpainter on July 12, 2010, 01:56:09 AM
Quote from: ian48th on July 11, 2010, 11:09:13 AM
Thanks for the advice.  After loosening and retightening, the stiction range is about 13mm as opposed to 15mm. 

Is there a recommended replacement interval for the fork seals?  My bike is ten years old with 22,000 miles.

I've never seen anyone replace them unless they were leaking.
Title: Re: fork stiction and front axle
Post by: corey on July 12, 2010, 04:53:19 AM
Quote from: ian48th on July 10, 2010, 12:12:16 PM
Thanks for the link to the PDF.  It says the nut is a 28mm.  Sears had 27 and 30, so I'll check elsewhere for that. 

I don't have a front stand, so I'll have to look into that.

Try Autozone (if you have those near you). I got a dura-last brand socket for my axle for like $4.99, and it has worked perfectly thus far.

For a front stand, if you are on a budget, the T-Rex racing stands work very well. You can get a combo fork/triple tree stand for under $100.

http://t-rex-racing.com/catalog.php?item=48 (http://t-rex-racing.com/catalog.php?item=48)
Title: Re: fork stiction and front axle
Post by: ian48th on July 12, 2010, 07:33:22 PM
Glad to hear I shouldn't worry about replacing fork seals; mine are not leaking.  And I've never heard of fork seal grease.  I'll see if the local shops have that.  Local being Victoria, British Columbia.