907 sprocket ??

Cybermunster · Post by **Cybermunster** » Fri Aug 17, 2007 1:29 am

anyone know offhand how many teeth on the OEM rear sprocket for the 1991 907s?

thanks

Tamburinifan · Post by **Tamburinifan** » Fri Aug 17, 2007 9:32 am

40 according to the FAQ here.

Cybermunster · Post by **Cybermunster** » Fri Aug 17, 2007 10:22 am

Mmmm...if I go to a 37 teeth, anyone done this mod?
You guys think it's worthwhile? How about top end?

The bike has Staintune cans, K&N a/f, and chip.

I'm actually happy with it's performance as is, just considering the sprocket swap.

Thanks!!

Tamburinifan · Post by **Tamburinifan** » Fri Aug 17, 2007 12:07 pm

Mmmm...if I go to a 37 teeth,

Why, lower revs?

I bought mine w 15/39, felt weak to me.
Now w 14/39 I like it. 5th feels cool until 120km/h, 6 th still an overdrive.
14 is hard to get nowadays so I will probably go 15/41 or 42 next time.
Just my 2c.

Finnpaso · Post by **Finnpaso** » Fri Aug 17, 2007 1:28 pm

I use 15 / 46(!!!) gearing and never go back to normal anymore. Fits much more better to my driving style...

Btw, near all modern Ducatis are geared from factory too low, to meet allkind of noise and emission, etc standarts... Same with original exhaust systems. Its quite rare to see, that someone drive his/her Ducati with normal gearing or with normal exhaust pipes...

:laugh: :laugh: :laugh:

Tamburinifan · Post by **Tamburinifan** » Fri Aug 17, 2007 2:00 pm

Posted: Fri Aug 17, 2007 2:28 pm Post subject:

--------------------------------------------------------------------------------

I use 15 / 46(!!!) gearing

Ever tried speedway? Think the gearing would work!

Finnpaso · Post by **Finnpaso** » Fri Aug 17, 2007 7:26 pm

Many times...(but too expensive to me, cause after 3 hour driving good tires are ready to change

) and i like drive fastly in twisty roads. I like to use just ALL gears in twisties, where speed is not "so high", like in motorways, which are very boring to Ducaties.... Surely driving style is very important, if thinking gearing. If need to drive fastly in German motorways, then need surely lower gearing. I hate such roads, so thats why i use big rear sprocket.... Btw, 750 Paso gearing dont need so much changes, but 907 and ST4S needs totally different, than OEM sprockets. Sorry, i wanted to say, that ALL ST modells need!!!

Btw, that gearing depends very much about race track. If shorter track, then higher gearing and via versa...

Cybermunster · Post by **Cybermunster** » Sat Aug 18, 2007 6:00 am

I'm looking to lower the revs when doing 60+ mph so I guess a 42 would be my best bet?

Tamburinifan · Post by **Tamburinifan** » Sat Aug 18, 2007 10:46 am

What gearing have you had until now?
If you`ve had less than 42 rear it will rev more at 60 w it.

Cybermunster · Post by **Cybermunster** » Sat Aug 18, 2007 2:06 pm

right now I have the stock, original gearing so I figure if I go with a 42 it should be LESS revs at 60mph for example. Correct?

Tamburinifan · Post by **Tamburinifan** » Sun Aug 19, 2007 10:36 am

No. Bigger rear = higher RMP at 60.
42 higher revs than 40.

mrinflux · Post by **mrinflux** » Tue Sep 11, 2007 1:37 pm

Stock gearing for 907ie chain wheels is: 15/40

I'm running 14/42 on all my 907ies and prefer it. I went down one tooth in the front and up two in the back.

Since the front chain wheel is smaller, going down one tooth in the front has more impact on power delivery than going up one tooth in the rear. Going from 15 to 14 teeth reduces the circumference of the front chain wheel by almost 7%; increasing the rear chain wheel to 41 teeth only increases rear chain wheel circumference by 2.5%)

h1a · Post by **h1a** » Tue Sep 11, 2007 2:11 pm

http://www.xs4all.nl/~ator0437/gc/

This link is to a gearing calculator.

Cybermunster · Post by **Cybermunster** » Tue Sep 11, 2007 9:51 pm

As usual...great info and help!! much appreciated guys!

blakduc1 · Post by **blakduc1** » Tue Sep 25, 2007 6:59 pm

My 1992 907ie came with a 40 tooth rear and 15 tooth front, I believe. The 40 is nice easing along for long jaunts at 70 or 80, like intersate highways. But--- it will likely not pull top end speed with the 40 tooth rear. Theoretically gives you more top end speed with the 40, but if it can't attain it, what good is that? I use 42 tooth on both my 907s and it gives better power, easier clutch actuation at take-off, and will pull top end easier. I have used 41 tooth also, but not a lot better than 40.
I say use 42, even though rpm will be a little higher at a given speed. Better for mountain road running....

dp

907 sprocket ??

907 sprocket ??

stock/modified gear ratios