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Author Topic: How to internally lower your forks. Updated with better pics. 6/20/09  (Read 66844 times)

Offline Patterson

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Re: How to internally lower your forks.
« Reply #25 on: February 18, 2009, 07:24:14 PM »
i'm in the north part of GA. thanks for the offer, i should be able to get it i was just messing with ya

Offline horndog

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Re: How to internally lower your forks.
« Reply #26 on: February 20, 2009, 05:58:03 AM »
Good job Coreyonbusa, this is defiantely one on my list. My only question though is what are the tolerances on the o.d and i.d figures you have quoted on your post? Did you get the spacers machined up or did you have an available pipe that meets the dimensions quoted? What material did you use as well?

 :?:

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #27 on: February 20, 2009, 03:00:20 PM »
Good job Coreyonbusa, this is defiantely one on my list. My only question though is what are the tolerances on the o.d and i.d figures you have quoted on your post? Did you get the spacers machined up or did you have an available pipe that meets the dimensions quoted? What material did you use as well?

 :?:

Good questions. :thumb:

7/8 od is as big as I would go, just because you want the oil to be able to travel freely around it. The 5/8 id a little big for the same reason.
 If you have time when you have the forks apart, measure for yourself. Maybe you'll find a size that works better? :thumb:

 I had a machine shop make mine for me, out of steel.



Offline horndog

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Re: How to internally lower your forks.
« Reply #28 on: February 21, 2009, 07:08:23 AM »
:thnks:

Offline busa20

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Re: How to internally lower your forks.
« Reply #29 on: February 24, 2009, 02:32:59 PM »
 :thumb: :thumb:
kawkiller

Offline Cookie

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Re: How to internally lower your forks.
« Reply #30 on: February 27, 2009, 12:29:53 AM »
Fabulous write up, Cory!  :thumb:  :thumb:
-Chris

גַּבְרִיאֵל guide me to the light ישוע המשיח

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #31 on: February 27, 2009, 06:00:53 PM »
Fabulous write up, Cory!  :thumb:  :thumb:

Thanks bud!

Offline jimmygsxr

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Re: How to internally lower your forks.
« Reply #32 on: March 01, 2009, 01:46:19 AM »
I will have to put this mod on my to do list, thanks Coryonbusa. :thumb:
05 blue/silver gen3 pc3r air shifter nos lowered 4" over arm RPM lock up

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #33 on: March 01, 2009, 04:40:44 AM »
:thumb:

Offline horndog

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Re: How to internally lower your forks.
« Reply #34 on: March 07, 2009, 04:25:46 AM »
Just to be difficult, I have another question :) I was talking to a local guy the other day who has had his forks modded although he did not take anything off the original factory spacers but just added the extra 2" spacers. He tells me that is what I should do as it preloads the forks and prevents striking the sump on the deck if a wheelie lands too hard. He also mentioned that it is a bit of a mission geting the spacers in due the compression required to fit the additional spacers.

Is there any opinions/experiences on this?

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #35 on: March 07, 2009, 05:24:47 AM »
Just to be difficult, I have another question :) I was talking to a local guy the other day who has had his forks modded although he did not take anything off the original factory spacers but just added the extra 2" spacers. He tells me that is what I should do as it preloads the forks and prevents striking the sump on the deck if a wheelie lands too hard. He also mentioned that it is a bit of a mission geting the spacers in due the compression required to fit the additional spacers.

Is there any opinions/experiences on this?

I can see where he did have a hard time getting the springs back in if he didn't cut down the factory spacer. :D

Adding the lowering spacer does lower the valves assembly into the cartridge. No amount of preload can change that as it is set by the lowering spacer.

 By not cutting the factory spacer, you are adding TOO much preload to the factory spring which will cause it to bind and ride REALLY stiff. You might as well tighten down a lowering strap, it's the same thing.
 By cutting down the factory spacer, you give the front end back it's suspension. Allowing you to tune it in for your riding style.

Here's a rough illustration I made showing the spring binding.


Offline horndog

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Re: How to internally lower your forks.
« Reply #36 on: March 07, 2009, 06:01:13 AM »
Thanks Corey. I am talking about drag only bikes so there wont really be much of a difference in riding style but I can still see how the spring bind could be caused which can be very dangerous if no travel is available in the forks.

I will be sticking with your described set up but with a little less off the factory spacer, heavy hitter style as I am big boned  "not fat"  :hys:

 :thumb: :thumb:

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #37 on: March 08, 2009, 07:58:25 AM »
I hear ya! I'm in the same boat! :lol:

Good luck with it. :thumb:

Offline SteveB

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Re: How to internally lower your forks.
« Reply #38 on: March 19, 2009, 05:55:21 PM »
Thanks Corey. I am talking about drag only bikes so there wont really be much of a difference in riding style but I can still see how the spring bind could be caused which can be very dangerous if no travel is available in the forks.

I will be sticking with your described set up but with a little less off the factory spacer, heavy hitter style as I am big boned  "not fat"  :hys:

 :thumb: :thumb:
We aint fat!!!
We're just fearful cuddly! :hys:

Offline lee8sec

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Re: How to internally lower your forks.
« Reply #39 on: March 22, 2009, 05:17:00 AM »
Did mine today, good  writeup. If you heat up  the threaded joins on the damper tube & valve assembly with a hot air / heat gun they undo alot easier (factory use loctie). Just becareful of the damper seal. Make sure the inner hole in your new spacer is big enough to sit on the flat edge of the valve assembly, not jam on the taper where the threaded section is. Leigh
« Last Edit: March 22, 2009, 05:19:00 AM by lee8sec »
We are the people that our parents warned us about.

Offline horndog

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Re: How to internally lower your forks.
« Reply #40 on: March 22, 2009, 06:46:36 AM »
Did mine today, good  writeup. If you heat up  the threaded joins on the damper tube & valve assembly with a hot air / heat gun they undo alot easier (factory use loctie). Just becareful of the damper seal. Make sure the inner hole in your new spacer is big enough to sit on the flat edge of the valve assembly, not jam on the taper where the threaded section is. Leigh

So that would then be a minimum id of   :?: :?: :?: to avoid jamming on the taper.

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #41 on: March 22, 2009, 09:11:19 AM »
Did mine today, good  writeup. If you heat up  the threaded joins on the damper tube & valve assembly with a hot air / heat gun they undo alot easier (factory use loctie). Just becareful of the damper seal. Make sure the inner hole in your new spacer is big enough to sit on the flat edge of the valve assembly, not jam on the taper where the threaded section is. Leigh

Why do you not want the spacer on the tapered edge of the valve assembly?

Offline lee8sec

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Re: How to internally lower your forks.
« Reply #42 on: March 22, 2009, 03:31:38 PM »
I used alloy spacers. On take off as the forks extend & top out it will hammer the spacer on to the taper section, flairing the end. Leigh
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Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #43 on: March 22, 2009, 03:44:30 PM »
I see your point. :thumb:

Offline lee8sec

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Re: How to internally lower your forks.
« Reply #44 on: March 22, 2009, 03:55:50 PM »
I like your spring compressor design, will help out people who dont have a press at home.Mine is similar, has a bearing sperator on one end. Its always good to see people like you, who share info, so others can learn to do things them self. The photos make it better.  :idea: :thumb:Leigh
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Offline lee8sec

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Re: How to internally lower your forks.
« Reply #45 on: March 22, 2009, 04:02:14 PM »
Matt, check your other pm's.  leigh
[/quote]

So that would then be a minimum id of   :?: :?: :?: to avoid jamming on the taper.
[/quote]
« Last Edit: March 22, 2009, 04:04:13 PM by lee8sec »
We are the people that our parents warned us about.

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #46 on: March 22, 2009, 04:28:50 PM »
I like your spring compressor design, will help out people who dont have a press at home.Mine is similar, has a bearing sperator on one end. Its always good to see people like you, who share info, so others can learn to do things them self. The photos make it better.  :idea: :thumb:Leigh

Thanks! I plan on re-writing soon, with better pics. :thumb:

Offline dave3.4

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Re: How to internally lower your forks.
« Reply #47 on: March 22, 2009, 07:16:34 PM »
 that mean your going to lower them a little more?


I like your spring compressor design, will help out people who dont have a press at home.Mine is similar, has a bearing sperator on one end. Its always good to see people like you, who share info, so others can learn to do things them self. The photos make it better.  :idea: :thumb:Leigh

Thanks! I plan on re-writing soon, with better pics. :thumb:

Offline Coryonbusa

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Re: How to internally lower your forks.
« Reply #48 on: March 23, 2009, 04:49:36 AM »
that mean your going to lower them a little more?



Yeap!   :wink:

Offline horndog

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Re: How to internally lower your forks.
« Reply #49 on: April 25, 2009, 08:49:29 AM »
Got my spacers made and am getting ready to fit them. A mate asked me today how much lower the forks will be after fitting a 2" spacer and I said........Good question.

Is it a 1:1 ratio with the fitment of the spacer? ie 2" spacer = 2" lower on the forks

Also what weight fork oil do you suggest for a heavy hitter?