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Hi!
I (always had) have problems with my tyres, they seem to be too high. The front tire uses to raze on the front part of the front fender, the rear is on the plastic where the ECU is behind, the tire now starts eating my ECU! Tire is Bridgeston BT21 170/17.
I wonder whats wrong, as the wheels should be the original (?) 17" wheels...by the way I´m driving more than 50.000m that way

My tire dealer says, it could be, that the rear shock suspension does not work correctly (my Marzocchi looses air pressure from time to time...), but could that be the reason??

What is your experience? Whats wrong?

br
Gernot

Yes that is due to your rear shock adjustment. I couldn't be bothered to alter mine on while taking the missus for a short pillion ride down some very bumpy back roads. Apart from the neck pain I got from the abuse and back slaps I also managed to rip into the rear fender/mudguard.

Have you manually adjusted it correctly ?

do you use the original size rear sprocket (and chain length)? Just wondering as if you`d use a bigger one w/o a longer chain the wheel may be positioned further to the front than normal.

paso750 wrote:do you use the original size rear sprocket (and chain length)? Just wondering as if you`d use a bigger one w/o a longer chain the wheel may be positioned further to the front than normal.

I have a 42t rear sprocket with the standard chain length and don't get any contact issues.

It might be lowered by some mechanic, cutting the rear spring.
You had the bike brand new or used?

The rear sprocket is 1 tooth less- so it´s almost standard, the rear spring is original (It is a 1991 bike, I have bought it 1993 directly from the dealer it was a testing bike). The tension of the spring is set to the first third- so it´s quite soft.
I wonder if the first batch of 907 had maybe 16" wheels and some of the early 17" bike were not modified to fit with 17" wheels?

My 907 is # 215 and came off the factory with 17" wheels (and 300mm rotors)

My guess is that you are over 17 stones, maybe were carrying a passenger and you had soft settings or a shot shock.

The Duoshock had 3 settings, spring load (hight), compression and rebound, and in theory it should not touch the mudguard.

50K miles is a lot for a shock, i think is time for you to get it reconditioned, I did mine at 20K miles and the bike seems completely different (and much better!!)

The other thing are the tires... the exact meaurements for our 907s are 120/70-17 and 170/60-17; The rear can be fitted with the 180/55-17 (Ducati will give you the letter for the MOT if necessary)

I wonder if you , by any chance, fitted it with the 170/80-17 (and the correspondent 120/80-17 at the front) , that would explain why it is touching.

You can try to tension harder the spring and push the hydraulic lifter. More have a look to the chain tensioner. it can be twisted upward or downward.Here's a pic from mine, setted to downward. As you can see, it helps me to have some space more for my 17" rims

By the way... Don't care about the tyre label!

No eccentric adjusters on the 907 though. Same set up as the Monster and 851 with conventional sliding blocks and draw bolts.

Hi Gernot,

Just a question: what's your body weight?
The reason I ask is that the spring rate on all Paso's is on the soft side, no problem if you are a 65/70 kg Italian but if you, like me weight 95 kg (in the nude!) the spring rate is not sufficient.
A shock absorber dampens shocks but the spring is solely responsible for the geometry of the bike.
And since the Paso has a lot of wheel travel it will eventually hit the fender if the spring is to soft.
So check your weight/spring rate ratio !

For the Paso you need for 110 kg (me + full gear) a 85 n/mm spring.
Standard mine had 50 n/mm which is much to soft for my weight.

You could order yourself a new one (spring) by Hyperpro, Wilbers (depends where you live) for about 120 €.

Good luck and lot of driving fun!

Frank

Oh, I didn't remember how the adjuster was like!

for those of us 14 stones or more a new spring is a good idea for the rest just crank up on the preload till you get the design spec with yur small arse in place. there are hundreds of articles on the net on how to set-up any suspension

ok, i will try some things in spring, i.e. change my personal setup from 80 to 60kg
changing the spring (haha) rate...

or just drive her as it is.

thanks in the meanwhile!

Hi ynot,

your spring is too soft. I had the same issue and had to replace the plastic fender.
1) measure the unloaded height of the rear between two points which are easily accesable.
2) measure the of the rear sitting on the wheels.
3) measure the height of the rear when your sitting on the bike and your tones on the pavement to keep your balance.
4) remove or unload the spring to determine the maximal travel of the rear
the difference between 1 and 2 is your negative sag, which is important to your roadholding
1 to 4 is your total travel
1 to 3 should be app 25 to 30% of the total travel.
by these measurements you can determine the required stiffness of the spring.

Bertus