If you can wait a week, I can measure that part when I get back home.
Mate a would advise you don't use PVC tubing, it has a nasty habit cracking and collapsing under load and the load on your front end even under mild braking or dump absorption will be significant which could mean you front end effectively collapses.
Fittiing Hyperpro fork springs, which are something like 10% stiffer depending on what kit you've got, for your weight was the wrong way to go.
You could well find you need to do nothing more other than set the sag, if not you can now play with oil weight, 10 may be too much or you need 12, 15 etc.
Perhaps I should clarify: I'm not going to be using the PVC permanently
Once I've got the spacer the right length to get the sag correct (I've also bought some penny washers for fine adjustment), then I'm either going to cut down the OEM spacers or get some new ones made up
I don't think so. I looked at this carefully for quite a while and the OEM springs are a) 14 years old and b) too soft anyway, so I wanted something that had a bit more resistance, but simply adding preload to the existing ones could have resulted in the spring becoming rigid under hard braking.
Hyperpro supply 15W fork oil with the springs, but that will, of course, only affect the damping, so I'll wait until I've got the preload right before I start playing with that.
Also, of course, if I get too much dive, I can adjust the air gap, but that's the last stage.I did try out the new springs, taking the bike up to 60mph and then doing a hard stop (not quite full on emergency stop) and I'm using about 80% of the maximum fork travel, which is ok.
Quote from: Grahamm on 28 July 2020, 12:07:53 pmPerhaps I should clarify: I'm not going to be using the PVC permanently It could crack/collapse the fist time you hit a bump or brake and riding around like a little old lady isn't going to give you the feed back you need, but hay it's your life mate, but have a thought for others.
That's why you need the correct weighted spring for your weight, to give you the right sag.
Many owners/riders have their bikes set way too hard dampening wise, also what's going on at the back end has a big effect to what's happening at the front.
QuoteHyperpro supply 15W fork oil with the springs, but that will, of course, only affect the damping, so I'll wait until I've got the preload right before I start playing with that.Hyperpro supply a spring which is normally 10- 20% higher than standard, if that spring weight is more than your weight requires, no matter how much you cut off, it wont effect the strength, only it's travel over a given distance. If the spring is progressive an you cut the wrong end off it will in a dramatic way.
Also if you in/decrease the spring you alter the rake which again effects the handling.
QuoteAlso, of course, if I get too much dive, I can adjust the air gap, but that's the last stage.No, dive is or high speed damping is controlled by the shim pack
Also, of course, if I get too much dive, I can adjust the air gap, but that's the last stage.
not the air gap, by reducing the air gap all you're doing is slightly increasing spring pre load, which in your case is too high already.
The oil level determines how much the fork goes "in" when you brake hard. So changing the oil level, does nothing when riding normal.The oil thickness determines how much damping you have in the fork. More or less weight will not change the amount of damping you need.What does help, is to reduce the spring preload: since we use progressive springs, they have a softer and harder area.By reducing the preload , the spring will work in a softer area, giving more comfort.There is a spacer on top of the spring. If you cut off say 10mm, the spring should be in the right range and will give you the ride you want.Instead of cutting the original ones, making a set of new ones is often easier (since the material is quite thin, it is hard to saw or cut)The new one may be made from steel, aluminium or PVC.Often swer pipe (for instance) has the proper outer diameter and is quite cheap and easy to cut
As I said above it's your life, you may get away with all of it, but if you don't someone could well have to come a clear you off the road. Even if you do get away with it, you won't get a good set up, but it's all up to you.
I don't think you've quite understood what I was saying.
It could crack/collapse the fist time you hit a bump or brake and riding around like a little old lady isn't going to give you the feed back you need, but hay it's your life mate, but have a thought for others.
The point is that the progressive spring is already being compressed somewhat by the spacer, which is why the sag is out.
By shortening the spacer, fewer of the spring coils are being squeezed down, thus giving more sag.
See my other post about about setting the sag on the YSS shock
Who said anything about cutting down the spring? I'm talking about shortening the spacer which compresses the spring.
Of course I can always raise the forks if necessary.
There is no shim pack on the FZ6 forks.
Err, as far as I'm aware, the air gap above the oil level has nothing to do with the preload!
To directly quote a guy from Hyperpro:The oil level determines how much the fork goes "in" when you brake hard. So changing the oil level, does nothing when riding normal.
The oil thickness determines how much damping you have in the fork.
More or less weight will not change the amount of damping you need.
What does help, is to reduce the spring preload: since we use progressive springs, they have a softer and harder area.By reducing the preload , the spring will work in a softer area, giving more comfort.
If you cut off say 10mm, the spring should be in the right range and will give you the ride you want.
Instead of cutting the original ones, making a set of new ones is often easier (since the material is quite thin, it is hard to saw or cut)The new one may be made from steel, aluminium or PVC.Often swer pipe (for instance) has the proper outer diameter and is quite cheap and easy to cut
I'm quite willing to take advice if it benefits me, but what you're saying appears to be contradicting what I've had from Hyperpro themselves or watching eg Dave Moss's videos.
There's every possibility you'll be in trouble withing minutes, do you really want to find out as you hit a bump or brake form 60mph?
QuoteThe point is that the progressive spring is already being compressed somewhat by the spacer, which is why the sag is out. By shortening the spacer, fewer of the spring coils are being squeezed down, thus giving more sag.Yep that's why I've suggested putting the standard springs back in they're 10-20% less than Hyperpro and the sag will be much closer if not correct and it's your dampening that's wrong, not the springs
The point is that the progressive spring is already being compressed somewhat by the spacer, which is why the sag is out. By shortening the spacer, fewer of the spring coils are being squeezed down, thus giving more sag.
QuoteI'm talking about shortening the spacer which compresses the spring. the standard spacer is such that the spring is almost at it's non compress length
I'm talking about shortening the spacer which compresses the spring.
it's the Hyperpro spring that's wrong, it's too hard for your weight, so whatever you do to it, it is not going to change it.
QuoteThere is no shim pack on the FZ6 forks.Yes there is, it's inside the damping rod.
Quote Err, as far as I'm aware, the air gap above the oil level has nothing to do with the preload!We all learn something everyday
Oil LevelA change in oil level will affect the air compression; it does not affect damping. However, too large an air gap in forks may cause forks to dive too fast. Conversely, if the oil level is too high with too small an air gap, it can have a significant effect on the last bit of fork travel.
QuoteTo directly quote a guy from Hyperpro:The oil level determines how much the fork goes "in" when you brake hard. So changing the oil level, does nothing when riding normal.He needs to be working somewhere's else then.
Adding/removing oil (changing the air gap) is just a cheap basic air spring i.e. preload.
QuoteI'm quite willing to take advice if it benefits me, but what you're saying appears to be contradicting what I've had from Hyperpro themselves or watching eg Dave Moss's videos.Mate, what you're doing is trying to rectify one mistake (fitting higher rated springs) by making and even bigger one. The advice given hear is given to stop you 1 potentially, seriously hurting yourself or wrecking your bike, 2 to help you solve your problem. If you don't to take it happy days, as I said earlier "it's your life" and you may well get away with it, lets hope you do.
Pretty that's the part that was taken out of my forks when I had some Racetech Emulators and springs fitted, so should be sat in a box in my shed.