Front sprockets are harder to come by in the US, but Talon Engineering in the UK will export them. Eventually, they will have US distribution for street sprockets as they do for dirt bike sprockets. Price with shipping is approximately $22, and if the sprocket is in stock shipping is about a week.
The Falco (and Mille) in the US come standard with 16 tooth front sprockets. You can raise the final ratio six percent, using your stock chain, by switching to a 15T sprocket. There doesn't appear to be any swingarm clearance problems with this change, although the chain may wear a bit faster (reducing the circumference of the chainring means the chain links must swivel a greater amount for each revolution, and less links are bearing the load of the drive force).
| The front sprocket lives behind the plastic countershaft cover. The first time you remove the shift lever, mark the shaft with a centerpunch to remember your spline alignment. | |
On the Falco, a single bolt and washer retains the sprocket. Place the bike in gear, step on the rear brake, and remove the bolt (it does turn counterclockwise to loosen). Because of the tight clearances, you'll need to remove the sprocket before removing the chain. This takes a lot of chain slack, so it may be easier to remove the rear axle, drop the wheel, and remove the chain from the rear chainring. The sprocket is removed by sliding it off the splined countershaft.
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The clearances are tight. Its doubtful a 17T sprocket would fit. A lot of chain slack is needed to slide the sprocket off the splines because the chain will hit the frame. |
As you remove the old sprocket, pay attention to which side was facing out. It's important to get the offset correct for chain alignment, and this sprocket is asymmetrical. Its conventional for the number of teeth to be marked on the side of the sprocket facing away from the engine (or wheel in the case of a rear sprocket). The sprocket teeth should be closer to the bolt head than to the motor cases (the wider boss faces in). Before replacing the new sprocket, grease the splines, not as a lubricant, but to prevent rust which gets rubbed away and eventually increases tolerances. Grease the sprocket teeth too, as it needs to break in to the old chain. This is probably the time to say never put a new chain on worn sprockets, or a new sprocket on a worn chain. Replacing all components at once will give the longest component life, but I doubt this is as economical as only replacing worn components.
| Like the original, the new sprocket is made of steel (as any 15T sprocket on a 100 HP bike should be). The Talon Engineering sprocket appears to be cadmium-plated and looks as strong, if not stronger than the original. Fit to the countershaft was excellent. | 
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Slip the chain on the new sprocket and slide it onto the countershaft splines. Being smaller than the original, there should be a bit more clearance to work. Clean the threads of the retaining bolt, Loctite it (use thread locking compound), and tighten it (clockwise) with the bike in gear and the rear brake on. The torque spec for this bolt is 36 ft-lbs or 50 Nm which is not a lot. You don't want to damage the threads in the countershaft, as the cases would have to be split to replace it. Finish up by replacing the countershaft cover, shift lever, rear wheel and adjusting the chain slack.
| Sprocket retaining bolt torque: | 36 ft-lbs (50 N-m) |
It's a good idea to take a few easy miles with a lubed chain, then pull over and check the chain for shiny spots or metal shavings. If all looks OK, enjoy your newly placed powerband.
| Final Ratios Using Stock Chain | |||
| Countershaft sprocket | Chainring | Final Ratio | |
| Stock SL | 16 | 41 | 2.56 |
| 15T sprocket | 15 | 41 | 2.73 |
Update April-2006: I replaced the front sprocket again, this time using a slightly more expensive part from Sprocket Specialists (part no. 623). I had a moment of doubt, as the sprocket wasn't broached completely and only fit on the countershaft one way (what I thought was the wrong way!). After checking the sprocket alignment a few times, I was sure that the sprocket needed to be reversed so the numbers were facing out. This required a few passes of a file on the internal teeth to finish up the machining, after which the sprocket slipped on the spline freely. The moral is to be careful: if your sprocket only slips on one way it may be due to sloppy machining and not on purpose.
Continue to some drive force charts for the Falco.
Continue to a discussion of wheelbase.
Go back to the Falco home page.