The Spitfire was not just good for keeping ME109s on the go, it also does wonders for the PX gearbox, thanks to the boys at DRT.
This newly produced input shaft assembly is CNC machined from tough steel and then hardened. It is therefore more able to withstand extreme levels of performance, convinces through durability and so presents an optimal addition to the performance orientated input shaft assemblies available on the market at this present time. They also enable a more precise gear ratio tuning process, so allowing the creation of a gear box perfectly assembled for the individual needs of each particular motors power delivery characteristics.
The standard input shaft assembly comes equipped with 4 gear cogs and they have 12, 13, 17 and 21 cog teeth respectively. The DRT ROAD version comes with 12-13-16-20, so the 3rd and 4th gear is a little shorter.
The DRT Racing one with 12-13-16-20 is again shorter in the 4th gear.
Standard or mildly tuned motor setups can also benefit from the improved gearbox precision that this Spitfire conversion kit provides. The following gear cog combinations have, over time, proved successful: The PX125 with 58, 42, 38 and 36 teeth on the respective cogs and for the PX150 and 200cc motors cogs with 57, 42, 38 and 35 teeth respectively.
For tuned motors the DRT gear cogs are the most appropriate, the 1st gear having 55 teeth, the 2nd gear cog with 41 teeth, the 3rd gear cog with either 36/37 or 39 teeth and the 4th gear cog with 36/35 teeth enables clean acceleration through the whole of the gear range. Varying the number of teeth on either the clutch cog or the primary driven cog can also raise or lower the overall gear ratio of your motor.
Helpful Hint: Some DRT gear cogs are not compatible with this input shaft conversion kit. These are for the 2nd gear the gear cog with 40 teeth and for the 4th gear the cogs with either 37, 34 or 33 teeth. Use the kickstart gear 11352600 in combiantion with the Spitfire one.
Conclusion: DRT make simple and effective gear ratio tuning possible for everyone.
SIP-TIP: Do not forget to order a new fixing nut for the input shaft, a safety washer, new bearing and fresh gearbox oil for safe and enduring use of your motor. A new primary drive repair kit should also be included in every major service.
New: Vespa 125 GT 1°/3°/GTR/TS/150 GL 2°/150 Sprint 1°/3°/V/P125-150X 1° pilots can be happy. DRT reduces with the 12-16-20-19 input shaft assembly the 4th gear. Best results in acceleration from the 3rd into the 4th gear possible!