Keeping my arse end on the ground

[Brian d marge]

without knowing the details , and struggling to understand the posts. from what I gather is that you feel like the bike is wanting to fire you over the handlebars under hard braking

ie the back is coming up too quick and the front is going down to quick . (too soft low speed compression and to quick rebound on rear ,)


there are plenty of how to's on this site ,

but in a nutshell get a bit of paper and a bit of road with a sweeper and a tight hairpin

set sags

1. laden
2. unladen ( if unladen sag incorrect , you probably have a lot of preload and need different springs )

set everything to the middle ( now that springs and sags are correct and you have binned that crappy stock shock that ,,,probably done 30 000 km )

if you have ohlins and they have high speed and low speed comp/ damping ,,, you are looking at the low speed

set comp until the bike doesn't pitch to quickly ... then your rebound at the rear slow that down so that the attitude of the bike is trim under hard braking .

Now go through the sweeper at a constant rate , the bike should track a constant radius all the way through , without and correction from you ,,, the front shouldn't drift out towards the outside or the bike shouldn't turn into the inside of the turn


If in doubt , set to the middle and leave well alone , All the people on KB who work with suspension are very accessible willing to help ,

kind regards Stephen

typed quickly so , someone else may elaborate a bit better than I

[MotoKuzzi]

My 2c worth.

Too much pre load on the front causing the front to sit lower, along with soft compression damping causing it to dive,

Too much preload at the rear making it sit up causing weight transfer to the front along with slow rebound on the back causing the rear tyre to lose contact.

Is the front lowered in the triple trees?

[Brian d marge]

My 2c worth.

Too much pre load on the front causing the front to sit lower, along with soft compression damping causing it to dive,

Too much preload at the rear making it sit up causing weight transfer to the front along with slow rebound on the back causing the rear tyre to lose contact.

Is the front lowered in the triple trees?

you might want to re think that one ,,,,, pre LOAD ,,a spring will want to return to its original position ,,, so if you screw the top down the spring will do its bit and the bike will rise ,,,until it tops out ,,,,,,,,

Stephen

[racefactory]

I'm not sure if they come like this stock but yes the forks are poking through about 7mm.

[MotoKuzzi]

you might want to re think that one ,,,,, pre LOAD ,,a spring will want to return to its original position ,,, so if you screw the top down the spring will do its bit and the bike will rise ,,,until it tops out ,,,,,,,,

Stephen

Apparently with my Guzzi front springs, increasing pre-load causes the forks to settle downwards when the spring shortens as it is compressed, don't know if this true of other bikes. The opposite occurs at the rear where winding on pre-load forces the eyes of the shock further apart. Be interested to hear if other bike front forks are the same.

[MotoKuzzi]

I'm not sure if they come like this stock but yes the forks are poking through about 7mm.

I have set my Guzzi up with the forks protruding about 15cm through the top triple trees to try and improve turn in on the corners, factory settings are at level. I believe it transfers weight to the front which I guess would affect the ability of your rear tyre to maintain contact under heavy braking? Interestingly I had the opposite problem with the Guzzi front dampers hydaulic locking and consequently only getting about 60% fork travel. Braking was horrendous. I've since fixed it and now get full travel under heavy braking and can just lift the rear If I give it all I can, but I stop a lot quicker with it set up this way.

[Brian d marge]

Apparently with my Guzzi front springs, increasing pre-load causes the forks to settle downwards when the spring shortens as it is compressed, don't know if this true of other bikes. The opposite occurs at the rear where winding on pre-load forces the eyes of the shock further apart. Be interested to hear if other bike front forks are the same.

and I doubt its true with Moto Guzzis either , having a cartridge style fork , you might be thinking of rebound , as winding that down will not allow the forks to return in time and pack down

Get a spring , squash it together , release one end, its the same inside a m/c front end

Stephen

[CHOPPA]

I havnt bothered to read the whole thread.... Put an indicator on the fork to see if it bottoming out under braking. Id prob just put in a firming spring if it were my bike but an easy way of sorta doing the same thing is by winding on more preload.

Another thing that you should consider is to buy some stomp grip. It goes on your tank so you can grip the bike hard with your knees, this does 2 things to help in your case.... 1st is that it keeps your ass back in the seat and weight over the rear wheel and secondly when your braking the load from your body is applied certrally on your bike rather then through your arms and directly into the forks.....

Id be looking at riding style before suspension

[Sensei]

If you are lucky enough to own the Race Tech's - " Motorcycle Suspenion Bible " then read though it & it will tell you just what you need to do with out guessing this or that , or Pm / E-mail Robert T & let him tell you ......

[racefactory]

As I've said, no weight on arms during braking, gripping tank, not bottoming out under braking- just about 1cm of travel left with hardest braking on average road.

Update- I think it was a combination of not enough preload and compression damping with the raised forks causing too much weight on the front.

Can get the tyre chirping now and the bike sits better under hard braking, noticeably better, but still the rear wheel comes up... guess that's just a sportbike geometry + sticky tyres for you. I thought it was possible to lock the tyre on all bikes.

[Brian d marge]

I havnt bothered to read the whole thread.... Put an indicator on the fork to see if it bottoming out under braking. Id prob just put in a firming spring if it were my bike but an easy way of sorta doing the same thing is by winding on more preload.

Another thing that you should consider is to buy some stomp grip. It goes on your tank so you can grip the bike hard with your knees, this does 2 things to help in your case.... 1st is that it keeps your ass back in the seat and weight over the rear wheel and secondly when your braking the load from your body is applied certrally on your bike rather then through your arms and directly into the forks.....

Id be looking at riding style before suspension

just IMHO


I try to use as little preload as I can , as well it stores energy in the spring , with must be controlled by damping ... ie the less energy I can add to the system the better , , so I try , as you pointed out , to get the springing right before I do anything else ..

I used to have an old guy here in Japan who would wind springs for .,... FREE ,,, but he has retired now ..so I must reach into pocket ,,,,

Stephen

[SPP]

... Check out my BLOG on emergency braking.
http://www.kiwibiker.co.nz/forums/en...rgency-Braking

...

You do like to research eh I even got 'round to reading it (eventually). Nice one, cheers. The AMSF approach seems to suit me best. I'll stick with that.

[CHOPPA]

As I've said, no weight on arms during braking, gripping tank, not bottoming out under braking- just about 1cm of travel left with hardest braking on average road.

Update- I think it was a combination of not enough preload and compression damping with the raised forks causing too much weight on the front.

Can get the tyre chirping now and the bike sits better under hard braking, noticeably better, but still the rear wheel comes up... guess that's just a sportbike geometry + sticky tyres for you. I thought it was possible to lock the tyre on all bikes.

I raced this model and the braking ability of the bike is amazing

[Shaun]

As I've said, no weight on arms during braking, gripping tank, not bottoming out under braking- just about 1cm of travel left with hardest braking on average road.

Update- I think it was a combination of not enough preload and compression damping with the raised forks causing too much weight on the front.

Can get the tyre chirping now and the bike sits better under hard braking, noticeably better, but still the rear wheel comes up... guess that's just a sportbike geometry + sticky tyres for you. I thought it was possible to lock the tyre on all bikes.

Too much oil in the forks can cause this also, as it will sit on a wall of fork oil that cannot go any where, causing what is known as Hydraulic locking, causing the rear to lift in the air

[pritch]

I'm not a suspension guru, but I have a book by a guy who might be...
And I haven't read the whole thread either.

But anyway he says,

"Rear wheel comes off the ground or slides - reduce rear rebound damping"

Sportbike Suspension Tuning, Andrew Trevitt, David Bull Publishing, 2008