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Discussion Starter #1 (Edited)
My new Ducati Scrambler Classic is fast becoming one of my favorite motorcycles. In stock form though, it has a number of “issues” that I want to address - the first being a gearing change.

The stock gearing on this bike is biased toward acceleration, making the “scram” a hoot to ride around town (wheelies galore!) but a bit buzzy on the highway. After riding mine for a couple of weeks I've decided the stock gearing is too short for my purposes. I'm willing to trade raw acceleration for lower engine RPM’s at higher speeds.

One of the nice things about having a bike with chain & sprocket drive, is that it makes changing your gearing ratios so easy. This is usually accomplished by changing out either the front or rear sprockets (or both). Fitting a sprocket with more teeth on the front will make the gearing “taller” - less teeth “shorter”. On the rear the opposite is true - bigger sprocket means shorter gearing, smaller results in taller.

The stock sprocket sizes for the Ducati Scrambler are a 15 tooth front and 46 tooth rear. As I wanted taller gearing, I either had to fit a larger front or smaller rear. Usually, the easiest way to accomplish this is to just change out the rear sprocket, as it entails less labor to do so - but since the Scrambler is a new model, my options there were limited. Most of the rear sprockets that are available right now, and would fit made of hard-anodized aluminum instead of steel - not ideal for someone like me who rides a lot of miles - so I elected to change out the front instead. The other bonus in this particular situation is that the stock chain length can be used without any alteration.

After consideration, I decided a change in the front sprocket from 15 teeth to 16 teeth would benefit me the most. Here is an image illustrating the RPM’s of this bike using the stock gearing...



And another, showing the changes with fitting a 16 tooth front sprocket...



To perform this modification, you will need to procure a replacement sprocket - Driven Racing is usually my vendor of choice for this, their part number for a 16 tooth front sprocket - which is a proper fit for the Scrambler - is “1067-520-16T”.

You will also need access to the following tools and shop supplies:

  • Size H5 Hex Bit
  • Size H8 Hex Bit
  • 24mm Socket
  • 30mm Socket
  • 8mm Socket or Wrench
  • Blue & Red Loctite
  • A suitable rear stand or other mens of supporting this bike (other than just the side stand - more on this later)
This is a relatively easy modification that should take no longer than an hour to complete - lets get started...

The first step is to loosen the rear axle nut and back off the chain tension. Use the 30mm socket for the axle nut, with a breaker bar - it is torqued very tightly, then the 8mm socket or wrench to loosen the chain adjusters on both sides of the swing arm.

After this is finished, remove the front sprocket cover using the H5 bit to remove the 3 bolts as shown...



While it is possible to change this sprocket without removing the left-side passenger peg support rail, it is difficult. Taking the extra 5 minutes required to do this is HIGHLY recommended,

To do this, first remove both the linkage bolt to the shifter assembly and the bolt attached to the exhaust CAT, using the H5 hex bit at the locations highlighted in RED, then using the H8 hex bit, remove the 2 bolts at the locations shown in BLUE.

Before doing so, I hope you are using a rear stand - or other suitable means - to support the bike. The side stand is going to come loose when you remove the larger bolts!



Next, remove the bolt bolt shown below using the 24mm socket. You can then slide the passenger peg rail off and out of the way.



Next, remove the 2 bolts on the front sprocket retaining washer, then rotate the washer slightly to line up with the splines on the counter-shaft and remove it too...



Now... slide the sprocket off the shaft and replace it with the new 16 tooth version. Re-install the original retaining washer, using red loctite on the 2 bolts.

As you can see for the following picture, there may be a clearance issue at the locations shown in red, below...



The black plastic part highlighted in blue in this picture is just a cover with some sealing o-rings - apparently this area was for a hydraulic clutch actuator used on other bikes that utilized the same motor.



I removed this “plug” to show the detail - you do not have to remove it.

You may, however elect to remove some material on the side of the boss the this plug covers - to alleviate the lack pf clearance highlighted earlier. I took a die grinder and removed less than 1/32″ from the upper area (the lower I left alone). Clearance issues may vary on your particular bike due to manufacturing variances.

To finish up, Install the passenger peg rail in reverse order of dis-assembly using blue loctite on all fasteners.

Then fit the plastic sprocket cover with the 3 bolts using blue loctite.

Re-tension and realign your chain - then re-torque the rear axle nut - and you can go out for a ride.

I think that this is a significant improvement for this particular bike. I’m no longer reacher for “7th gear” at higher speeds, and there is much less shifting at lower speeds, while just tooling around.

Originally posted on my personal blog @ www.moto-graphic.com
 

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Discussion Starter #4
Great write up, but boy do I miss the days when this seemed to be a 10-20 minute job on most other bikes I used to own.
It actually only took me 20 minutes, but the tutorial is geared toward those with less experience and I didn't want them to rush.


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How is the bike now at stop-to-start? It's a torquey little bugger with the regular gearing, does a 16T solve the "catchiness" of the throttle or help even things out from a standstill?
 

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Discussion Starter #6
How is the bike now at stop-to-start? It's a torquey little bugger with the regular gearing, does a 16T solve the "catchiness" of the throttle or help even things out from a standstill?
Yes, noticeably so.
 

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Thank you for taking the time to write that up. It will come in handy for lots of folks when it comes time to start modding their scramblers.
 

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I'm not sure anyone knows the answer to this yet, but does putting the bigger sprocket on the front affect the top speed capability in 6th gear? I've done this on bikes in the past where the engine couldn't overcome the wind in its top gear and you'd end up having a higher top speed for the bike by downshifting.

Or is the Scrambler geared so short that this doesn't matter and 6th gear still yields the bike's top speed? My other bikes that suffered from this have under 50 horsepower.

For years I ran a +1 tooth sprocket on my Kawasaki 650 to make it run smoother at interstate cruising speed but then I learned that 5th gear has a lower top speed than 4th gear because the engine doesn't have enough steam to push the bike and me through the wind.
 

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Discussion Starter #9 (Edited)
Yes, the bike has enough HP to push to the rev limiter in 6th gear - even with the 16t sprocket (personally verified).

Though you will, however, have to lay out on the gas tank like Rollie Free to get there.

 
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For the layperson:

I am not a gearing whiz, but running different tooth counts will change your engine output results due to that gearing.

You will get higher top speeds when you gear up, and more grunt when you gear down. Think about a bicycle. When you turn the cranks with your legs, that is the same as the engine horsepower. When you are on a big ring up front and a small ring out back: stop to rolling is super hard, but you will be able to turn the crank fewer times to cover more ground at higher speeds. When you are on a small ring up front and a big ring out back: you can pedal your butt off and not really go anywhere, but getting off the line is easy.

If you want to pull wheelies all day long, and grunt to get out and around cars in tight traffic? Slap a smaller sprocket (up front) on there. You will trade top speed for low end grunt.

Are you a long distance rider, that wants tall gears? Go bigger (up front), and you will get higher top speeds and will ease up to them. Here, you are trading low end grunt for easy top speeds. You will have to gas and slip the clutch more though.

From the factory, they have to decide what the best compromise is to keep the ride spirited and the gas mileage happy.

*Edited for accuracy.*
 

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Discussion Starter #11
For the layperson:

I am not a gearing whiz, but running different tooth counts will change your engine output results due to that gearing.

You will get higher top speeds when you gear up, and more grunt when you gear down. Think about a bicycle. When you turn the cranks with your legs, that is the same as the engine horsepower. When you are on a big ring up front and a small ring out back, stop to rolling is super hard, but you will be able to turn the crank fewer times to cover more ground at higher speeds. When you are on a small ring up front and a big ring out back, you can pedal your butt off and not really go anywhere, but getting off the line is easy.

If you want to pull wheelies all day long, and grunt to get out and around cars in tight traffic? Slap a bigger sprocket on there. You will trade top speed for low end grunt.

Are you a long distance rider, that wants tall gears? Go smaller, and you will get higher top speeds and will ease up to them.

From the factory, they have to decide what the best compromise is to keep the ride spirited and the gas mileage happy.
While what Nick is saying here is certainly true, it only applies to changes made to a rear sprocket. Changing the counter-shaft sprocket (the subject of this thread), will have the opposite effect (larger front sprocket = taller, smaller front sprocket = shorter)
 
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While what Nick is saying here is certainly true, it only applies to changes made to a rear sprocket. Changing the counter-shaft sprocket (the subject of this thread), will have the opposite effect (larger front sprocket = taller, smaller front sprocket = shorter)
Guh! Yeah. He is right. I get them turned around. I am going to edit my original post so that it is correct.
 

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Can you tell me the which Ducati model the sprocket fits doesn't list the scramblervia your link so I can track down one in the UK
Thanks
 

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Discussion Starter #15
Can you tell me the which Ducati model the sprocket fits doesn't list the scramblervia your link so I can track down one in the UK
Thanks
2009 Ducati Monster 696 (among others, I would assume), make sure you specify a 520 chain pitch.
 
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I saw this post on your website. Please keep them coming. I find this and the Tutoro oiler incredibly helpful, especially for those first-timer. Thank you very much !
 

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No discussion needed really ! it does what the write up states. Life is easier on move off, less sensitive throttle. Not noticed any real difference in acceleration. Mway speeds still pull 120mph with ease, and gets there fast enough! 7th gear? I still occasionally go for a 7th lol
 

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primary interest was less shifting to mitigate overall wear and tear on the small clutch pack... is this sound rationale?! Thoughts (discussion)...
 
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