Spring spacers

[Jackrat]

Iv'e read that old VW valve springs make good fork spring spacers for beefing up the front end on bikes like mine.Thing is how do you put them in??.
The articule I read didn't go into detail but I'm sure he ment just put them in on top of the existing springs but how do I push them down and replace the fork caps??.

[FROSTY:Me]

I wouldnt bother dude.throw the old springs away and fit a set of progressives.You will not believe the difference in ride.
If you dont want to go to that expense a compromise will be to cut 2 sections of 25mm (1") water pipe and insert them on top of your springs.
I found with old xj650/750s that 15mm was enough to get rid of the sag out of my springs

[pete376403]

Iv'e read that old VW valve springs make good fork spring spacers for beefing up the front end on bikes like mine.Thing is how do you put them in??.
The articule I read didn't go into detail but I'm sure he ment just put them in on top of the existing springs but how do I push them down and replace the fork caps??.

A socket that fits the fork cap and a T bar to turn it. That way you can push down on the centre of the T bar while someone else turns it. Obviously you want the bike on the centre stand or a crate so the weight is off the front wheel.
But you're still better to go with new Progressive springs. I put a set in the GS (which is very nose heavy cos of the big fairing) and they cleaned up the front ends act so much it could now be loosely described as "not bad"

[FROSTY:Me]

replacing a fork cap is heaps easier as a two man job.
If your fork caps are the screw in type then yep the t bar thing works pretty good.I usually apply the same principle but use a rattle gun and extention bar to get it started.
If your fork caps are the other type with an internal circlip retaining em you might need to do a bit of preperation first.
I usually spray wd40 or crc556 liberally around both circlips at least an hour before touching the darn things.
I do the whole forks fully extended thing to take pressure off the cap then get a use internal circlip pliers to squeeze the circlip inwards -usually the springs are so sagged out that there is no pressure on them and the fork cap will just slide upwards.
once you have the spacer on top of the spring I'd get a mate to push down on the fork cap whilst you insert the circlip.
One thing I would do for certain. seeing as the forks are apart anyways I would drain the forks and put fresh fork oil in. Maybee 5 weight heavier than factory.

[pete376403]

[QUOTE=xjxjxj]replacing a fork cap is heaps easier as a two man job.
If your fork caps are the screw in type then yep the t bar thing works pretty good.I usually apply the same principle but use a rattle gun and extention bar to get it started. QUOTE]
Feck, you're brave! Rattle gun? Too easy to get a crossed thread and before you know it, there goes your fork cap, plus a whole heap of stripped thread material down into the fork tube.

[Jackrat]

Cool thanks,Thats what I thought he ment.
Now Question #2.Who can supply progressives in Auckland.
Thanks.

[F5 Dave]

Just about any shop can order them in from the distributor.

Just talking about spacers & particular using ‘Booster’ springs on top of springs:

Adding spacers will increase the preload raising the ride height & affecting the bump required to move the wheel initially but not thereafter if you see what I mean. ie: it doesn’t change the spring RATE. The only way to do this is to increase the wire thickness, to some small extent the material, the diameter & pitch of the windings. Or the amount of free coils. The less free coils the stiffer the spring rate. Think of bending a ruler with your hands touching & again at opposite ends. Which leads to the next point:

Booster springs: Total Bolocks I’m afraid. It just adds more free coils leading to a softer spring rate. The writer of the article you read obviously mistook the increased preload for a stiffer spring.

[Jackrat]

This has become more of an issue since I put on a second disc up front.
My front end on my bike was never that hot from new but now Iv,e got better brakes she bottems right out under firm braking.The real odd thing it that it sets down in a fairly controled manner then at the last second does a big dive.
A bit unnerving if your about to enter a corner hard.
The old saying that you can't change one thing without affecting another is certainly true in this case.

[F5 Dave]

Well strictly speaking when you put a 2nd calliper on a single system then the master cylinder should be replaced for one big enough for a 2 calliper system as well as it changed the hydraulic ratio. Having said that I’m not convinced the japs were totally up with the play in that area in the 70s so a bit of retrospective R&D may be in order.

Another point or few, the brake lines will be well overdue for replacement & will be seriously spongy. When fitting braided lines (see other posts regarding legality) to old Yams they then felt wooden as the master cylinder ratio seemed chosen to cope with spongy lines & if anything needed to be smaller when braided lines were fitted. Or maybe another calliper might even things out?!

Further it would be worth checking while you have the front end out that the forks are straight, this might explain the final dive & stick type behaviour. Or the discs may be warped/coned. This often gives a shudder from high speed or a grab/let go grab/let go feeling dragging the brakes at low speed.

[Jackrat]

I checked both discs when I fitted them,they are ok.
The master cylinder is the same on even the factory bikes that did come out with twin discs.This is a subject that gets lots of atentsion on the XS owners web site,Some guys go to the 750-850 master cylinder but don't report any real improvment over the standard one.My brakes are now quite good compeared to what they were but the lines will be replaced in the near future.
The springs in the front end have always been crap since I got the bike,I think/hope the better braking is just highlighting this.
I have the funny feeling there may be a bit of a flex issue being highlighted as well.I rang Mt Eden mc this morning and they have the correct progressive
springs in stock $195.00.Those guys rock!!
I am also putting tapered steering head bearings in to replace the standard cup an ball type.Then we will start on the rear end.
Ikon shocks and bronze swing arm bushes=$$$$$$$
I might even get there one day
Thanks for the thought provoking post.

[F5 Dave]

Bronze s/w bushes shouldn’t be too expensive. Many bearing shops should sell bushes. They will be the wrong size most likely but they are pretty cheap & you should be able to get some that are maybe the right ID & find some one with a lathe to turn them down to correct size. As for the shocks, well yes. You could try those Hagons which might be cheaper. Progressive do make shocks too, they are a bit average. I had some on a GS11 & they were much better than stock but lost their edge 10k k on.

As far as flex goes, many will suggest a fork brace. Usually limited improvement as the flex occurs in the tubes & triple clamp. Tying them together is of small benefit & would be better done at the axle. Some modification here so that a bigger axle was used (maybe different bearings are available) & that both the forklegs clamped directly onto the axle, not a spacer would be a better mod.

In addition forkbraces often promote stiction if not exactly spaced. And when the forks flex are they going to stay even?

Ideally you want to reduce the bending area by lowering the triple clamps & making those clamps clamp a longer area. But this will affect ground clearance & really you are starting down a path too far from the bike’s design parameters.

[merv]

Just to add to everything mentioned above, while putting spacers (and/or extra small springs) at the top doesn't change the spring rate of the original spring, remember that if they are linear in their rate you have by compressing the spring moved up a linear step on the force versus displacement curve. So in effect from that point the springs are stiffer in every respect.

e.g. (as a pure guess and assuming linear rate) if the spring rate is 1kg/mm and the original preload is say 20mm then at that point the load to make the spring compress must exceed 20kg. Compressing the forks say 100mm will require another 100kg i.e. 120kg all up.

Fit a 20mm spacer and the initial load rises to 40 kg and the total at 100mm fork compression to 140 kg i.e. a step up of 20 kg at every point. In effect the forks do get stiffer, but it can make the ride on reasonably smooth surfaces quite bumpy.

Progressive springs on the other hand have a non linear rate i.e. they are soft initially, stiffening up as you compress them. So they may well be able to maintain the initial 20 kg in my example above while also supporting a load of 140 kg at 100mm compression. This leaves the springs soft for cruising smooth higways, but harder when you hit the big bumps. Does that help explain it?

As for fitting springs I have always been able to refit the top caps by hand by simply pushing down on a socket and rachet or a ring spanner. They are not that hard, if they were your suspension would be like a rubber block. To assist though make sure your bike is supported on a stand, or use a tie down on the handlebars and pull it up by some hook in your garage ceiling so the forks don't compress at all and if necessary just have one cap off at a time. Simple huh. Me being a small guy I have done this on most of my bikes because I usually have to take preload spacers out to get a softer ride. Except on the VFR as it has adjustable preload screws on top of the forks.

[Jackrat]

Bronze s/w bushes shouldn’t be too expensive. Many bearing shops should sell bushes. They will be the wrong size most likely but they are pretty cheap & you should be able to get some that are maybe the right ID & find some one with a lathe to turn them down to correct size. As for the shocks, well yes. You could try those Hagons which might be cheaper. Progressive do make shocks too, they are a bit average. I had some on a GS11 & they were much better than stock but lost their edge 10k k on.

As far as flex goes, many will suggest a fork brace. Usually limited improvement as the flex occurs in the tubes & triple clamp. Tying them together is of small benefit & would be better done at the axle. Some modification here so that a bigger axle was used (maybe different bearings are available) & that both the forklegs clamped directly onto the axle, not a spacer would be a better mod.


In addition forkbraces often promote stiction if not exactly spaced. And when the forks flex are they going to stay even?

Ideally you want to reduce the bending area by lowering the triple clamps & making those clamps clamp a longer area. But this will affect ground clearance & really you are starting down a path too far from the bike’s design parameters.

Yes the axle only clamps on one side,a brace combats that but the fork tube flex you pretty much have to live with.Stiction is another thing the XS is well known for.That's an easy fix with RD400 seals and scrapers.I put Hagons on a Triumph I had years ago,They didn't last long.
I talked to the OZ supplyer of Ikons and he says they are just Konis renamed after Koni stopped making bike shocks.I'm going to pick up the progressive springs tomorrow,What's the bet an XV front end apears on Trade me the next day. :spudwhat:

[F5 Dave]

Yeah all the usual suspects in the aftermarket twin shock brigade are very crude low tech, even Koni’s which won’t be helped as they are made in Taiwan or somewhere now (note the word play IKON, move the I). There are of course high level brands like Ohlins but good luck affording them. I had a set of Marzzoccis on my earlier GS & they were okish & good value. Or maybe they were just so much better than stock & I knew no better. That’s more likely I guess.

[Jackrat]

Merv,What you are saying is pretty much what they say on the progressive web site.
I get it but it makes my head spin
Dave, the Ikon shocks are made in OZ.Some how that dosn't fill me with a lot of confidence but I am going on the advice of another XS rider that has them and so far so good.Another XS rider I met resently uses DT360 shocks.They have an oil resiv' thing so you can change the oil wheight plus they are rebuildable.I followed him down HW22 and his bike ran like it was on rails.It was watching him that made me get off my bum an do something about the poor handling of my own bike.I'll let you fella's know how it feels with the progessives tomorrow.