PRELOAD FORK CAP - Wrist Twisters
 
Thread Tools Display Modes
post #1 of 28 Old 02-20-2013, 02:03 AM Thread Starter
Tirone
 
Backlash's Avatar
 
Join Date: Nov 2012
Location: Norway
Posts: 51
Rep Power: 1
 
PRELOAD FORK CAP

I'm looking for aftermarket adjustable fork caps for the Honda 919 02/03, but I can only find for the 599 Does anyone know if these fit the 919? Or is there any other models that have the same dimensions of the fork? For example, CBF 600?

Backlash is offline  
Sponsored Links
Advertisement
 
post #2 of 28 Old 02-20-2013, 02:08 AM
Silent Service
 
modular's Avatar
 
Join Date: Nov 2012
Location: The 'nati
Posts: 47
Rep Power: 1
 
I would email or call Slingshot Racing and ask them if the 599 version will fit the 9er. Don't see why they shouldn't as they are the same size. I have a pair on my 599 and they are nice quality units.

No matter how much you push the envelope, it'll still be stationary.
modular is offline  
post #3 of 28 Old 02-20-2013, 02:34 AM Thread Starter
Tirone
 
Backlash's Avatar
 
Join Date: Nov 2012
Location: Norway
Posts: 51
Rep Power: 1
 
Quote:
Originally Posted by modular View Post
I would email or call Slingshot Racing and ask them if the 599 version will fit
They didn`t know if it would fit the 919

Backlash is offline  
 
post #4 of 28 Old 02-20-2013, 02:41 AM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
K1w1Boy is offline  
post #5 of 28 Old 02-20-2013, 07:47 AM
The Cripple
 
Pvster's Avatar
 
Join Date: Nov 2009
Location: Phoenix
Posts: 8,765
Rep Power: 1
 
The 02/03 forks are NOT adjustable on the 919 to begin with. Not sure what the benefit would be for installing the caps? Can anyone fill me in?

Pvster is offline  
post #6 of 28 Old 02-20-2013, 10:47 AM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
It would just provide an external pre-load adjustment, to enable some fine-tuning of ride height, basically, not much more...

K1w1Boy is offline  
post #7 of 28 Old 02-20-2013, 01:46 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
I'll use this to harp on a picky point of mine.
Until the fork is at full extension, or at least until the top out springs begin to have effect, the adjusters are purely ride height adjusters and nothing else but.
By definition, preload does not change unless the spring length changes.
In the normal zone of fork travel, regardless of where you have the adjusters set to, the spring length remains a constant.
They are best thought of in terms of what they actually do.
They are RIDE HEIGHT ADJUSTERS.
Adjustable fork caps is OK as a term, as it is not misleading.
But preload adjusters is totally misleading.
There, rant done !

mcromo44 is offline  
post #8 of 28 Old 02-20-2013, 01:59 PM
The Cripple
 
Pvster's Avatar
 
Join Date: Nov 2009
Location: Phoenix
Posts: 8,765
Rep Power: 1
 
Oh cool, good to know K1w1boy and Mcromo. Thanks! Thought you had to have the internal dampeners to adjust ride height

Pvster is offline  
post #9 of 28 Old 02-20-2013, 06:28 PM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
Quote:
Originally Posted by mcromo44 View Post
I'll use this to harp on a picky point of mine.
Until the fork is at full extension, or at least until the top out springs begin to have effect, the adjusters are purely ride height adjusters and nothing else but.
By definition, preload does not change unless the spring length changes.
In the normal zone of fork travel, regardless of where you have the adjusters set to, the spring length remains a constant.
They are best thought of in terms of what they actually do.
They are RIDE HEIGHT ADJUSTERS.
Adjustable fork caps is OK as a term, as it is not misleading.
But preload adjusters is totally misleading.
There, rant done !
Hmm. Hang on.

Let's say the bike is on a workshop stand, forks fully extended, and the caps get wound in. This is shortening the spring length, isn't it, by reducing the space available inside the fork leg? And isn't the outcome of that putting more pre-load on it?

The effect, when the bike comes off the stand, is to alter ride height...

K1w1Boy is offline  
post #10 of 28 Old 02-20-2013, 07:29 PM
The Cripple
 
Pvster's Avatar
 
Join Date: Nov 2009
Location: Phoenix
Posts: 8,765
Rep Power: 1
 

Pvster is offline  
post #11 of 28 Old 02-22-2013, 03:40 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by K1w1Boy View Post
Hmm. Hang on.

Let's say the bike is on a workshop stand, forks fully extended, and the caps get wound in. This is shortening the spring length, isn't it, by reducing the space available inside the fork leg? And isn't the outcome of that putting more pre-load on it?

The effect, when the bike comes off the stand, is to alter ride height...
OK, letís first go back to one of my comments Until the fork is at full extension, or at least until the top out springs begin to have effect, the adjusters are purely ride height adjusters and nothing else but.
Next, letís imagine a reasonable build. Letís suppose one puts in a set of new springs, and for purposes of discussion, makes a spacer that will result in 10 mm of Installed Preload existing with the Front End Ride Height Adjusters fully backed out.
Next we re-install the front forks, put on the wheel, etc. and get the bike off the stands so it is resting on the shop floor nicely balanced by you straddling the bike or holding a bar end.
The front end will be in a state of equilibrium re ride height. Letís pretend you get a Free Sag of 15 mm. Keep in mind that the front spring will have settled upon a certain length, the number of which is irrelevant, aside from it being substantially less than the spring length when the forks were off the bike and in your shop.
Letís suppose you want less Free Sag because you want less Rider Sag. So you screw in your adjuster 2 turns which translates to 4 mm of change. You are in the travel zone of the fork, and what happens is that the steering head of the bike is lifted up by 4 mm (ignoring the trigí re the steering head angle just to keep things simple) as the fork tube is forced out by 4 mm as the adjuster lifts up the steering head upon the spring, while the spring length itself remains the same. Because the springís compressed length has not changed, the preload has not changed, and aside from some weenie weight transfer to the rear, the weight of the bike that the front wheel sees has also remained the same.
Therefore, the adjustment accomplished is front (chassis) ride height. The amount of resistive force in the springs is still the same, the compressed spring length is still the same, as is also the front tire contact patch weight upon the floor. More preload has not been applied.
And if any doubters remain, have a look at Andrew Trevittís excellent book Sportbike Suspension Tuning. Itís not just me singing this song !

Best Regards,

McTavish McRomo

mcromo44 is offline  
post #12 of 28 Old 02-22-2013, 03:41 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Smile

Quote:
Originally Posted by Pvster View Post
Got your fresh popcorn ready ????

mcromo44 is offline  
post #13 of 28 Old 02-22-2013, 04:22 PM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
Quote:
Originally Posted by mcromo44 View Post
Let’s suppose one puts in a set of new springs, and for purposes of discussion, makes a spacer that will result in 10 mm of Installed Preload existing with the Front End Ride Height Adjusters fully backed out.
.... So you screw in your adjuster 2 turns which translates to 4 mm of change. ... Because the spring’s compressed length has not changed, the preload has not changed....
Best Regards,

McTavish McRomo
Here's my challenge: Putting a spacer in place is considered pre-loading the spring. Right.

Winding the adjuster in 4mm has the same effect as making the spacer occupy 4mm more space, but you won't consider that the same as altering pre-load on the spring, and I don't get it. So when you say "the spring's compressed length has not changed", I'm lost - it seems to me that the length has indeed changed, by the 4mm taken up by the adjusters.

I'm not wanting to go black/white, right/wrong here, I just don't get [in a common-sense non-techie way] why one thing is considered pre-load, and the other is not.

K1w1Boy is offline  
post #14 of 28 Old 02-22-2013, 05:22 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by K1w1Boy View Post
Here's my challenge: Putting a spacer in place is considered pre-loading the spring. Right.

Winding the adjuster in 4mm has the same effect as making the spacer occupy 4mm more space, but you won't consider that the same as altering pre-load on the spring, and I don't get it. So when you say "the spring's compressed length has not changed", I'm lost - it seems to me that the length has indeed changed, by the 4mm taken up by the adjusters.

I'm not wanting to go black/white, right/wrong here, I just don't get [in a common-sense non-techie way] why one thing is considered pre-load, and the other is not.
Look at it this way, if the spring was getting shorter, why is fork length growing ?
No, the spring length stays the same, and the fork tube is moved out by the same distance that the adjuster goes in.

mcromo44 is offline  
post #15 of 28 Old 02-22-2013, 05:33 PM
The Cripple
 
Pvster's Avatar
 
Join Date: Nov 2009
Location: Phoenix
Posts: 8,765
Rep Power: 1
 
Wow this got interesting! I see your point K1w1...

Damnit Mcromo, now my head hurts....

Pvster is offline  
post #16 of 28 Old 02-22-2013, 05:38 PM
(-(-(-(-(- -)-)-)-)-)
 
andrewebay1's Avatar
 
Join Date: May 2009
Location: Seattle, WA
Posts: 6,883
Rep Power: 1
 
I read the book last year and I'm still lost. I do remember reading that adjusting preload (ride height) doesn't change the length as the length stays the same. But doesn't it change how much force is needed to compress the spring further when you change the height?

I'm missing something here and need to check the book. Mcromo, are you saying by adjusting the ride height (preload as many call it), the fork tube offsets because it's in its travel length so essentially nothing happens to the spring? What if you were to adjust further until you're out of that travel? Would that work? I take it at some point the steering stem stops getting pushed up and you're actually compressing the spring. Or is that when you've bottomed out..

I just confused myself. I need to read that book over

My classified(s):
Nothing at the moment

----------------
------------
---------
------
---
- '96 Race-retired GSXR 750 (Sold)
- '01 RC51 SP1 (Sold)
- '03 919

"Security is mostly a superstition, it does not exist in nature: avoiding danger in the long run is no safer than outright being exposed. Life is either a daring adventure or nothing."-Helen Keller
andrewebay1 is offline  
post #17 of 28 Old 02-22-2013, 07:52 PM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
Quote:
Originally Posted by mcromo44 View Post
Look at it this way, if the spring was getting shorter, why is fork length growing ?
No, the spring length stays the same, and the fork tube is moved out by the same distance that the adjuster goes in.
Yep, good, I see that, I'm actively adjusting the ride height.

But if my bike is on its stand, and the fork is topped out, and I've dropped the springs in, and used some spacers on top as I put the caps on, and THEN crank in a few more mm, it seems to me that I'm adding a bit more pre-load...It appears to me that it's the same phenomenon at work....

K1w1Boy is offline  
post #18 of 28 Old 02-22-2013, 08:39 PM
rmb
Let's go!
 
rmb's Avatar
 
Join Date: Aug 2009
Location: Sussex Couty NJ
Posts: 7,650
Rep Power: 1
 

Awards Showcase
Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance 
Total Awards: 9

Mcromo, I finally get it! But, when you increase the ride height (preload adjuster) you will raise the height but you will also increase the perceived tension a bit correct?

rmb is offline  
post #19 of 28 Old 02-23-2013, 07:15 PM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
It seems to me the reasoning, if it's valid, should also pertain at the rear of the bike, and yet...

https://www.wristtwisters.com/forums/f90/frozen-rear-preload-adjuster-32307.html

"New in the Box with full Ohlins warranty. This shock is the Ohlins HO201.
This fits Honda CB919 CB900F Hornet 2002 thru 2007.
This shock has a hydraulic preload adjuster, adjustable rebound damping, adjustable compression damping. (S46HR1C1S)
We will at no additional charge respring this shock for your weight, and preset all damping adjustments.
We are the largest Ohlins Retailer in the world, we have the largest inventory of any Ohlins dealer. If you are looking for any other Ohlins products please contact us
We are an Ohlins Certified Center, we can repair any Ohlins product.
If you have any questions about this shock or any Ohlins product, please contact us."

K1w1Boy is offline  
post #20 of 28 Old 02-25-2013, 05:04 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by rmb View Post
Mcromo, I finally get it! But, when you increase the ride height (preload adjuster) you will raise the height but you will also increase the perceived tension a bit correct?
Not quite, but you are on to something re what you perceive.
As you lift it up, you get more trail.
Rule of thumb is 1 mm more trail of lift for every 4 mm of sag.
That rule of thumb is predicated on steeper steering head angles, but let's keep trig math out of it to keep it simple.
More trail is more caster effect.
Also, as you lift up, you get a wee bit more steering tube angle.
All of this combines to slow down the steering a bit, more bar and body pivot point force is required for the same rate of chassis roll rate and chassis turn in. (chassis roll rate and chassis turn in are not the same thing)
Also, the word "tension" is normally associated with "rebound".
Seeing as we have not changed the spring length by using the ride height adjuster, the tension/rebound feel should be the same, and the respective spring energy : damping forces will still be the same.

mcromo44 is offline  
post #21 of 28 Old 02-25-2013, 05:16 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by K1w1Boy View Post
It seems to me the reasoning, if it's valid, should also pertain at the rear of the bike, and yet...

https://www.wristtwisters.com/forums/f90/frozen-rear-preload-adjuster-32307.html

"New in the Box with full Ohlins warranty. This shock is the Ohlins HO201.
This fits Honda CB919 CB900F Hornet 2002 thru 2007.
This shock has a hydraulic preload adjuster, adjustable rebound damping, adjustable compression damping. (S46HR1C1S)
We will at no additional charge respring this shock for your weight, and preset all damping adjustments.
We are the largest Ohlins Retailer in the world, we have the largest inventory of any Ohlins dealer. If you are looking for any other Ohlins products please contact us
We are an Ohlins Certified Center, we can repair any Ohlins product.
If you have any questions about this shock or any Ohlins product, please contact us."
I gotta laugh.
Things have been nuts work wise otherwise I'd have been back to you sooner.
I had a scrap of paper on my laptop that had a quick scratch on it that said "use rear unit analogy", then I see your post.
But my rear unit analogy is a wee bit different than yours.
Yours is predicated upon a fixed length shock that ups the preload on the spring such the the resistive spring energy goes up, so the spring compresses less once the bike weight is applied to it, and bike's rear end sits a bit higher.
Mine is predicated upon an adjustable length shock. To raise (or lower) the chassis, you leave the preload alone, and instead give the lower mount whatever amount of turns you want to get the rear ride height change you are after. Meanwhile, the spring length stays exactly the same. Just like the front end Ride Height Adjusters do for the front of the bike.

mcromo44 is offline  
post #22 of 28 Old 02-25-2013, 05:49 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Smile

Quote:
Originally Posted by Pvster View Post

Damnit Mcromo, now my head hurts....
I'm not done with your head yet ...................

mcromo44 is offline  
post #23 of 28 Old 02-25-2013, 07:09 PM
Community Moderator
 
g00gl3it's Avatar
 
Join Date: Jun 2009
Location: Idaho
Posts: 11,614
Rep Power: 1
  

Awards Showcase
Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance 
Total Awards: 3

Quote:
Originally Posted by mcromo44 View Post
I'm not done with your head yet ...................
oh... you didn't just do that....


2009 Aprilia Tuono - Ginger
2001 XR650R BRP (Big Red Pig)
2006 Honda 599 - Ex wrecked it :-D
2007 Honda CB900F (sold)
2006 Honda VTX 1300C (sold)
YouTube Channel
g00gl3it is offline  
post #24 of 28 Old 02-25-2013, 07:13 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Red face

Quote:
Originally Posted by g00gl3it View Post
oh... you didn't just do that....

Oh ???

mcromo44 is offline  
post #25 of 28 Old 02-25-2013, 07:15 PM
Community Moderator
 
g00gl3it's Avatar
 
Join Date: Jun 2009
Location: Idaho
Posts: 11,614
Rep Power: 1
  

Awards Showcase
Wrist Twisters Event Attendance Wrist Twisters Event Attendance Wrist Twisters Event Attendance 
Total Awards: 3

Show her my O face! - YouTube

2009 Aprilia Tuono - Ginger
2001 XR650R BRP (Big Red Pig)
2006 Honda 599 - Ex wrecked it :-D
2007 Honda CB900F (sold)
2006 Honda VTX 1300C (sold)
YouTube Channel
g00gl3it is offline  
post #26 of 28 Old 02-25-2013, 07:41 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by g00gl3it View Post
Excellent !

mcromo44 is offline  
post #27 of 28 Old 02-26-2013, 10:25 AM
Left of Centre
 
K1w1Boy's Avatar
 
Join Date: May 2011
Location: Auckland, NZ
Posts: 3,500
Rep Power: 1
 
Quote:
Originally Posted by mcromo44 View Post
I gotta laugh.
Things have been nuts work wise otherwise I'd have been back to you sooner.
I had a scrap of paper on my laptop that had a quick scratch on it that said "use rear unit analogy", then I see your post.
But my rear unit analogy is a wee bit different than yours.
Yours is predicated upon a fixed length shock that ups the preload on the spring such the the resistive spring energy goes up, so the spring compresses less once the bike weight is applied to it, and bike's rear end sits a bit higher.
Mine is predicated upon an adjustable length shock. To raise (or lower) the chassis, you leave the preload alone, and instead give the lower mount whatever amount of turns you want to get the rear ride height change you are after. Meanwhile, the spring length stays exactly the same. Just like the front end Ride Height Adjusters do for the front of the bike.
I see - good that we turned to this end of the bike, as it makes your point easier to grasp.

So this all pivots [for you] on whether the shock [or fork leg] can move up or down, in response to the tuning inputs, without the spring being impeded, or forced against a stop.

I think I've got you. I might not yet be an adherent, but I see the difference.

Thanks for the conversation.

K1w1Boy is offline  
post #28 of 28 Old 02-26-2013, 11:12 AM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by K1w1Boy View Post
I see - good that we turned to this end of the bike, as it makes your point easier to grasp.

So this all pivots [for you] on whether the shock [or fork leg] can move up or down, in response to the tuning inputs, without the spring being impeded, or forced against a stop.

I think I've got you. I might not yet be an adherent, but I see the difference.

Thanks for the conversation.
It was a great exchange.
We had some fun with it.
G'Day to you, sir.

mcromo44 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Wrist Twisters forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome