Topic: Cheap way to improve front suspension stiffness.

[754]

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..

[bill3749]

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.

[jeanhank]

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?

[andy750]

This link was posted recently regarding spring set up and suspension....hope it helps!

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

[Soos]

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

[crazypj]

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

[Hon3ybadger]

I'm no genius but why pvc or steel? Anyone try using aluminum to save weight over steel, but stronger than pvc?

[Jerry E.]

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.

[CB750R]

I've used old sockets from the junk tool bin as preload spacers too.

[crazypj]

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)

[goldarrow]

I use craftsmen sockets.

[Retro Rocket]

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..

[grcamna2]

When I can find the correct diameter I use thick flat washers stacked up.

[sloephuck]

Thanks liadio, I am going to give this s try:

Yes, even cheaper than those $65. Progressive springs... 

Got your attention?  You cheap ass!  (Like me!  )  Most of the newer bikes I've owned have all had preload adjusters on the top of the fork legs.  What this mod does is essentially add about an inch or so extra preload to the front. 


Follow your manuals instructions on how to change the front fork oil. 

When you have the top caps off:


Get some 1" PVC conduit, cut two pieces about 1.5" long.



Place on top of your existing springs.



Use a socket or wrench and push down hard on to the top cap as you screw down. (A socket is MUCH easier!!!)





Viola!  It'll be a little stiffer, and reduce braking sag.

I replaced the fork oil w/ Bel-Ray 10w oil at the same time as this cheap-ass mod and it feels a whole lot better now.