Interesting Progressive Spring Info

[YellowJacket!]

The other day I came across all teh good info in the tech section of the website.  One of the things was the instructions for the progressive springs. 

The instructions state that if you have air valves, to bleed off the air and NOT pressurize the forks if you use progressive spirings.

Why so?  Do any of you follow that advice?  I have progressives and run my forks at about 7 PSI.  Should I just bleed it to zero?

Thanks,

David

[Brian Moffet]

I have progressives, and I took all the weight off the front end, and opened up the valves.  Once they settled (so to speak) I closed them up and left them that way.  Seems to work fairly well, though I think they dive a little more than I would like.

Brian

[inanecathode]

If i ever bother with the progressive springs (why upgrade when you can straight up just replace it with something modern) i think i'll retain the air functionality. It's just extra spring rate, and they figure with the progressive spring you wont need any air but, im fat so there.

[treedragon]

and just to throw another aspect into the mix there are these  http://www.yss.co.th/pd_valve.php

Same principal as the Gold Valve emulators but cheaper. I think the 26.5mm ones are the correct fit. I am currently checking them out re exact pricing and size.

[Cdnlouie]

Where is the price list and can we get these in North America? They do look exactly like the Racetech one only in aluminum rather than brass. I have a Racetech valve emulator for my 82 purchased from the XS650 site and they were pretty cheap, about $65 which is a bargain  :o. I had the damper rods cut out by a machinist to install the XS model neatly inside the damper rod.  I installed one in my Venture Royale this year and it is a marvel.  I can't wait to get my Vision done after vacation.

I set the proper preload on my stock springs and don't require any air in my forks.  I discovered this after I converted the 82 to air shocks.  I would have to be really loaded to need the air.  Of course the 82 without the full fairing has less weight on the front and if you use the higher bars you are sitting back further which lessens the weight too.

An 82 with the right preload/proper sag setup does not need air (the stock 83 with the extra weight does seem to benefit from the air, but if preload was properly set for the rider it would probably be rarely used, as it is not a great suspension system).  Most 82 stock Visions are set up for about 130lb rider, way too light on the preload.  Adding about 1cm more PVC spacer works fantastic with stock springs.

Adding an emulator to that mix and it should be heavenly with major tunability and delightful compression damping for cruising over speed bumps, railway crossings, curbs and more with ease, and less dive with low speed braking, the improvements are like night and day.  The emulator really disposes of the need for the progressives which offer no real tuneability improvements other than a firmer suspension.

[Rick G]

I had  a 4inch pvc spacer on top of my stock springs , as I was tired of the nose diving on hard stops. But, this made the ride to harsh on concrete highway separations , so I went to 3 inch spacer and air. this way I can tailor it . Some day ,if I live long enough, I'll put the emulators in.

[The Prophet of Doom]

and just to throw another aspect into the mix there are these  http://www.yss.co.th/pd_valve.php

Same principal as the Gold Valve emulators but cheaper. I think the 26.5mm ones are the correct fit. I am currently checking them out re exact pricing and size.

They are listed on the YSS Australia site at $usd135, $aud160
No XZ550 on the application list though

http://www.yss-australia.com/products_yss_pdforkvalve.php

[pinholenz]

Trawling through the archives for suspension setups, I came across this thread from about 5 years ago (which I have high-jacked).

I have noticed the site that POD refers to in the last posting now has  XZ550 springs and PD fork valves listed. It also has an extensive manual for fitting.

http://store.suspensionshop.org/yamaha/xz-550-s/1980-1989.html

Under "information" this site has  Pdf's for fitting springs and suspension and a table to analyze and troubleshoot issues for fine tuning suspension.

All this is way beyond me - I am simply not a good enough rider to require such finesse. HOWEVER, I do need some basic advice on front and rear suspension sag recommendations for an XZ used for road riding. The suggested starting points on most sites is 30mm static sag front and rear.

Is that in line with forum users experience with the XZ?

Thanks

[The Prophet of Doom]

Racetech recommends 30-35mm front and rear. 
I had good experiences with that setting in the front.  The rear was nowhere near that even on full preload.  Hence the new shock

[pinholenz]

I have just downloaded "Race Techs Motorcycle Suspension Bible"

The dim light is beginning to shine a bit brighter and at last I am starting to feel that here is the basis of being in control. Still way too much information for my needs, but if I can get the XZ550 standard suspension to perform at its optimum for my needs, then that is a win. If I can understand the limitations, then that's a win as well.

Thanks for the direction

[The Prophet of Doom]

I made the stupid mistake of buying the bible as a kindle version, rather than PDF.  Kindle reader is PC only, and I have a Mac.  Sad Face.  I can read it on-line but it's very klunky.


Still, it's a good read  and highly recommended.  Racetech sell aftermarket nitrogen valves which should make the XZ shocks re-buildable (the ones that don't have welded up ends that is).  That's going to be my next project I think.


http://www.racetech.com/page/title/SPNV%20Installation

[dingleberry]

POD, I have a pdf of it in my dropbox. You want the link?

[The Prophet of Doom]

Yes please.