Contact breaker ignitions are usually prone to failure, of limited suitability for tuning and a major risk factor on long rides. Which is why they are often times replaced with electronic ignitions. To do so, fans of the Vespa 125 VNB/GT/GTR//Super/TS/150 VBA/VBB/VGLA/B/GL/Sprint/V/Super had only two options so far: They could either use a qualitatively arguable BAJAJ ignition, or go for the top quality but very expensive VESPATRONIC. Now SIP dealt with the problem at the suggestion of STOFFI’s Garage. The solution is the fusion of two crankshaft types, the base of which forms the classic Sprint crankshaft with its original oil seal and bearing housing. While the disc valve side remains unaltered, MAZZUCCHELLI equips the flywheel side with the revised cone of a modern PX.
This SIP crankshaft allows you to use the proven and low priced electronic ignition of the PX on your vintage Vespa. Oil seals and bearing remain original Sprint. Due to housing tolerances you might encounter minor difficulties when mounting the ignition. To avoid a modification of the stator plate or the damage of the cables, we advise you to use a spacer.
Conclusion: Perfect solution for an easy conversion to electronic ignition
Crankshaft / stroke 57mm / 20/25mm, M12
Conversion crankshaft (to PX ignition) with Ø 95mm crankweb (flywheel side), Ø 97,9mm crankweb (disc valve side), oil seal housing 20mm, bearing housing 25mm, large px cone with M12mm thread, incl. piston rod bearing
SIP-TIP: New keys, flywheel nut M12 and lock washer are a must. Don’t forget to order a stator plate and a flywheel for PX (e.g: SIP Touren, PX200 or HP4). A stator plate spacer (# 50011300) makes sense, too.
Robert Zinnöcker "Zini". STOFFI-SIP Racing Team: "We have been waiting for this for years. Finally a reliable and inexpensive way to convert the old sprint engines to electronic ignition. Perfect."