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-   -   749 front end? (/showthread.php?t=16997)

pedro 29-Apr-2005 21:43

749 front end?
 
has any one else had it? over say 120mph the front feels vague? im on pilot race tyres,i know they have a pointed profile etc,but have felt the same on the corsas too. ?:puzzled:

JohnDa 29-Apr-2005 21:53

I have had that on mine pedro, plus felt it was a bit vague in other areas ( on certain bends I know & under hard acceleration) as well. I have been to see Richard at maxtons today after speaking to him about it he adjusted the static sag to the rear shock.

I have since been out on it later today and I can say there is a very defiant improvement I am going to try it over the next few weeks, see how i get on.

I don't know if you've adjusted your setting from the factory, just thought id let you know how mine has felt and adjustments made.



[Edited on 29-4-2005 by JohnDa]

nathanhu 29-Apr-2005 21:56

hi pedro,
when i first picked up my old 999s it felt horrible at speed .
i changed the spring(as im alittle over 90kg:pig:)
and jacked up the rear of the bike two turns on the adjuster rod .
this made the world of difference and the bike tracked better into turns

pedro 29-Apr-2005 22:00

no,ive left it on stock settings,i too get it under hard acc too,feels planted in the bends though,i did scrape the belly pan last sat at cadwell on charlies 2. maybe its the rear?.. what did the do to your bike?

pedro 29-Apr-2005 22:03

Quote:

Originally posted by nathanhu
hi pedro,
when i first picked up my old 999s it felt horrible at speed .
i changed the spring(as im alittle over 90kg:pig:)
and jacked up the rear of the bike two turns on the adjuster rod .
this made the world of difference and the bike tracked better into turns
turning isnt the problem mate,its this feel as though the front tyre is not in contact with surface but it is?

JohnDa 29-Apr-2005 22:04

Have adjusted the pre-load on the rear to give a static sag of 9mm, he says anywhere between 5 - 10 mm 5 being the extreme! you'll know you have to much apparently as under hard braking the back will start to snake / step out etc

[Edited on 29-4-2005 by JohnDa]

nathanhu 29-Apr-2005 22:09

pedro how much do you weigh?

pedro 29-Apr-2005 22:09

around 12 stone

pedro 29-Apr-2005 22:14

how this sag work? hows is adjusted?

pedro 29-Apr-2005 22:18

hurry up i got my big hammer ready:roll:

ttstu 29-Apr-2005 23:07

C'mon we're still waiting!:sing:

keefer 29-Apr-2005 23:11

sag is the amount of movement at the rear end when the bike is on the paddock stand.
so if you stand at the back of the bike and lift up the rear (exhaust and seat)
you will notice that there is a small amount of travel, probably 10 - 15mm
the idea is to get it to travel less, ideally as others have mentioned about 5mm
you can achieve this by winding up the spring. (preload) making it firmer.
also try adjusting the ride height by a couple of turns as the ducatis are often set a bit kicked out from the factory.
this should give you a much better feel on the front.
just do it a bit at a time

andyb 29-Apr-2005 23:19

Static sag is the amount of travel between the rear wheel and the frame between having no weight on it to the weight of the bike. When you add the rider you have loaded sag.

If you raise the bike on an abba stand rear wheel free, you take a measurement from a mark on the rear subframe virtually above the wheel spindle to the rear spindle, you then put the bike down onto its wheels, bounce the rear subframe to let it settle, then repeat the measurements.

What the difference is, is your static sag! 5-15mm is a starting point.

HW 29-Apr-2005 23:22

Quote:

Originally posted by keefer
sag is the amount of movement at the rear end when the bike is on the paddock stand.
so if you stand at the back of the bike and lift up the rear (exhaust and seat)
you will notice that there is a small amount of travel, probably 10 - 15mm
the idea is to get it to travel less, ideally as others have mentioned about 5mm
you can achieve this by winding up the spring. (preload) making it firmer.
also try adjusting the ride height by a couple of turns as the ducatis are often set a bit kicked out from the factory.
this should give you a much better feel on the front.
just do it a bit at a time

Just need to watch that if it's a mono with an aluminium rear subframe that you don't lift it using the exhaust.subframe because it will flex and give you a false measurement. Use 2 people further forward where the subframe joins the frame instead. On bipostos the subframe is steel and less likely to flex.

There is a good guide for 749/999 suspension setup here (with specifics for Showa vs Ohlins shocks)
http://www.section8superbike.com/749-999suspension.htm

nathanhu 29-Apr-2005 23:35

sorry pedro i had to go and service something else for 30 mins :devil:

the effect of not enough rear spring preload on the bike is that the front steering angles( rake ) are increased ie like a chopper. this is because the rear of the bike squats to much with your weight acting on it.
to counteract this we ad more spring preload to the shock absorber ,this then pushes up/supports the rear of the bike against the added weight of the rider (the veriable in this equation) ................................
hic !!!!!! im drunk its time for bed ;)

V2 PETE 30-Apr-2005 00:37

front end felt great at 120mph at cadwell on sat , as was the rest of the bike . bit vague on the grass at 60mph though ! !

:frog:

HW 30-Apr-2005 06:26

Quote:

Originally posted by V2 PETE
front end felt great at 120mph at cadwell on sat , as was the rest of the bike . bit vague on the grass at 60mph though ! !

:frog:

So, what are you saying here? That the 749 is NOT suitable for Supermoto racing? Bummer ...

:sniff:

pedro 30-Apr-2005 08:55

Quote:

Originally posted by V2 PETE
front end felt great at 120mph at cadwell on sat , as was the rest of the bike . bit vague on the grass at 60mph though ! !

:frog:
that was down to you having a ding-dong with steve:sing: was good to see

butch890 30-Apr-2005 08:58

Pedro mate,fit the race kit-end of problem !!!!!!
front wheel only touches down at standstill !!!!
Butch

JPM 30-Apr-2005 10:57

Need to get mine sorted, I feel for me the rear is too soft by far, seems to squat down and thus I guess would make the front feel vague as all the weight is shifting backwards


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