Ducati Monster Forum

Moto Board => Tech => Topic started by: stopintime on October 21, 2018, 03:39:48 PM

Title: Primary drive gears different on SS / M ?
Post by: stopintime on October 21, 2018, 03:39:48 PM
The parts catalog shows SS (~750 2001) gear as a simple so-and-so many teeth gear vs the Monster gear which seems to be a dual version - one small and one larger gear in one piece....

Q1:
are they different?

Q2:
why? (oil pump differences?)
Title: Re: Primary drive gears different on SS / M ?
Post by: ducpainter on October 21, 2018, 03:54:26 PM
The US version shows the primary gears as being sold as a pair, with identical part#'s for both models.
Title: Re: Primary drive gears different on SS / M ?
Post by: stopintime on October 21, 2018, 04:08:14 PM
Quote from: ducpainter on October 21, 2018, 03:54:26 PM
The US version shows the primary gears as being sold as a pair, with identical part#'s for both models.

Yup - noticed that, but the drawing is clearly different. Maybe also clearly wrong  [cheeky]
Title: Re: Primary drive gears different on SS / M ?
Post by: ducpainter on October 21, 2018, 04:19:34 PM
Quote from: stopintime on October 21, 2018, 04:08:14 PM
Yup - noticed that, but the drawing is clearly different. Maybe also clearly wrong  [cheeky]
Different than which drawing?

Title: Re: Primary drive gears different on SS / M ?
Post by: stopintime on October 21, 2018, 04:23:29 PM
Quote from: ducpainter on October 21, 2018, 04:19:34 PM
Different than which drawing?



From SS to M
Title: Re: Primary drive gears different on SS / M ?
Post by: ducpainter on October 21, 2018, 04:33:23 PM
The US versions show the same drawings, and the 2 gears are not pictured together.

The crank gear is shown with the cranckshaft (with no part #), and the driven gear is shown with, and as part of, the clutch basket. The description with the part # states (pair).

Am I missing something?
Title: Re: Primary drive gears different on SS / M ?
Post by: stopintime on October 21, 2018, 04:41:20 PM
Quote from: ducpainter on October 21, 2018, 04:33:23 PM
The US versions show the same drawings, and the 2 gears are not pictured together.

The crank gear is shown with the cranckshaft (with no part #), and the driven gear is shown with, and as part of, the clutch basket. The description with the part # states (pair).

Am I missing something?

The drawings are different (on the crank shaft pages)
Title: Re: Primary drive gears different on SS / M ?
Post by: ducpainter on October 21, 2018, 04:51:55 PM
Not in the US versions.

They're identical...at least the ones I'm seeing. :-\
Title: Re: Primary drive gears different on SS / M ?
Post by: stopintime on October 22, 2018, 01:32:56 AM
Quote from: ducpainter on October 21, 2018, 04:51:55 PM
Not in the US versions.

They're identical...at least the ones I'm seeing. :-\

I'd better buy from a US bike then  ;D
Title: Re: Primary drive gears different on SS / M ?
Post by: Speeddog on October 22, 2018, 09:50:09 AM
There are different oil pump drive gears, those may correlate with:
a) Oil pressure relief valve in case/in pump
b) Big block/small block
c) ??

The oil pump drive gear is integral to the primary gear, not pressed on, so there's no swapping.

Generally bad form to mix-n-match parts from different gear sets, that's why they're sold in pairs.
If you must, start out riding easy with modest power, then slowly ramp it up over a couple hundred miles.
Gives the gears a chance to wear together a bit and get friendly.
Title: Re: Primary drive gears different on SS / M ?
Post by: stopintime on October 22, 2018, 12:09:54 PM
I ran "un-paired" primary gears a few years ago - didn't help to give them thousands of miles to mesh. Loud whining noise.

As Nate commented, the part number is the same and includes both parts of the pair (at $880 no less). I just wondered if they were completely different on SS versus Monster..... which could cause problems on my mix&match engine.
Title: Re: Primary drive gears different on SS / M ?
Post by: Speeddog on October 22, 2018, 12:50:05 PM
It may be possible to get a pair of gears that mesh and don't have huge backlash, yet are still wrong.
I think it's a corollary to (Jean Luc-)Picard's Law.

It's very common to 'cheat' gear profiles to get a slightly different ratio that's a smaller step than doing +1/-1 on the tooth counts.
I think every multi-speed transmission made even remotely recently is full of 'cheated' profiles.
Makes mix-n-match success very difficult.