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Author Topic: Cheap way to improve front suspension stiffness.  (Read 21589 times)

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Offline 754

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Re: Cheap way to improve front suspension stiffness.
« Reply #25 on: November 07, 2007, 09:14:06 am »
When you say a 1 inch long spring, are you talking a valve spring or other with finished ends?
Mentioning it because if you just cut one off someting and dress up the ends carefully, it is hard to match them, and not dressed up ends will grind away on parts..
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Offline bill3749

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Re: Cheap way to improve front suspension stiffness.
« Reply #26 on: November 07, 2007, 09:27:08 am »
The fork oil is the only thing I've got left to do on my 78 750K (Well as of this minute). I've tried to follow all the threads but I'm now confused as what to refill them with. Honda fork oil? 20W motor oil? ATF? I don't want to screw up here. I'm not after a rock hard ride either.

Offline jeanhank

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Re: Cheap way to improve front suspension stiffness.
« Reply #27 on: November 07, 2007, 11:42:39 am »
i used a springs i had laying around in a bin of parts... come to think of it, they were valve springs.

crazypj, i don't think i quite understand what you are saying regarding adding the spring rates.  why would the original spring with extra preload with a short length of stiff spring added end up making the forks shorter?  is that just because there are a few extra coils? 

come to think of it, does anyone know a lot about spring theory, and would care to give us a briefing?

Offline andy750

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Re: Cheap way to improve front suspension stiffness.
« Reply #28 on: November 07, 2007, 11:49:58 am »
This link was posted recently regarding spring set up and suspension....hope it helps!

http://www.yssusa.com/suspension_problems.html

Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico (CB750K4), 2003 - European Tour (CB750K4), 2004 - SOHC Easy Rider Trip (CB750K4), 2008 - Adirondack Tour 2-up (CB750K4) , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. VStrom DL1000 2003
4. XLR650L 2006

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Offline Soos

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Re: Cheap way to improve front suspension stiffness.
« Reply #29 on: November 08, 2007, 04:32:41 am »
Anyone be interested in metal spacers?

I made up quite a few sets for my cb650.
I made sets in 1/8" increments, from 1/4" to 1".
Made out of heat treated 416 stainless steel.
The 5/8" long spacers are not for sale, they are being used by me.

I'll sell the lot for cheap.

PM me if interested.


l8r

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(61mm)652cc 1979 cb650

Offline crazypj

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Re: Cheap way to improve front suspension stiffness.
« Reply #30 on: November 09, 2007, 11:53:35 pm »
crazypj, i don't think i quite understand what you are saying regarding adding the spring rates.  why would the original spring with extra preload with a short length of stiff spring added end up making the forks shorter?  is that just because there are a few extra coils? 

I remember you have to count the total number of working coils in a spring.
 When you fit different springs together they don't act as though they were two different springs, but like a single longer spring with more working coils.
 You may get a higher initial preload due to fitted length but overall the rate drops. (longer spring with more coils, its compressed further but the actual rate is lowered during total movement)
eg, a 100lbs/in spring plus a 150lbs/in spring doesn't get you 250lbs/in. It doesn't even get you 125lbs/in, its actually lower, but I forget the math and why (its actually pretty simple math but totally counter intuitive)
 I don't remember enough to explain it better, haven't looked at it for at least 6 yrs (sorry)
PJ
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Offline Hon3ybadger

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Re: Cheap way to improve front suspension stiffness.
« Reply #31 on: March 05, 2014, 01:11:22 am »
I'm no genius but why pvc or steel? Anyone try using aluminum to save weight over steel, but stronger than pvc?

Offline Jerry E.

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Re: Cheap way to improve front suspension stiffness.
« Reply #32 on: March 06, 2014, 09:58:10 pm »
My new progressive springs also came with PVC spacers to use. I left the spacers out, but used 1'' shorter front fork tubes, to lower my bike. Pretty much the same pre-load as with the spacers.
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Offline CB750R

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Re: Cheap way to improve front suspension stiffness.
« Reply #33 on: March 06, 2014, 10:27:24 pm »
I've used old sockets from the junk tool bin as preload spacers too.

Offline crazypj

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Re: Cheap way to improve front suspension stiffness.
« Reply #34 on: March 29, 2014, 09:28:43 am »
I did a set of Kawasaki 600 forks a few years ago, they used what looked like very thin PVC or Nylon spacers.
Owner wanted extra initial pre-load so I made some new spacers from PVC pipe about 1" longer than stock
The original Kawasaki spacer is on right and as you can see real thin wall


I also made modified spacers for my CB360 with Katana forks (needed lowering and less pre-load)

« Last Edit: March 29, 2014, 09:30:40 am by crazypj »
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Offline goldarrow

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Cheap way to improve front suspension stiffness.
« Reply #35 on: March 29, 2014, 09:58:13 am »
I use craftsmen sockets.
Life Is Full Of Challenges - And My Backyard Is Full Of SOHC4's

CB550 K0
CB750 K0, K2, K23 JDM, K45, K5
And the little ones z50r, xr50r, st90


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Offline Retro Rocket

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Re: Cheap way to improve front suspension stiffness.
« Reply #36 on: March 29, 2014, 04:07:10 pm »
I did a set of Kawasaki 600 forks a few years ago, they used what looked like very thin PVC or Nylon spacers.
Owner wanted extra initial pre-load so I made some new spacers from PVC pipe about 1" longer than stock
The original Kawasaki spacer is on right and as you can see real thin wall


I also made modified spacers for my CB360 with Katana forks (needed lowering and less pre-load)


I did this mod to one of my GPX750 kawasaki's about 15 years ago except i used a series of washers, it worked very well, major improvement..
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
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Offline grcamna2

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Re: Cheap way to improve front suspension stiffness.
« Reply #37 on: March 29, 2014, 04:20:14 pm »
When I can find the correct diameter I use thick flat washers stacked up.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S',1982' Suz. GS450TXZ
  I love the small ones too !
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