Dellorto and gurtner carburator aerox

English is not my first language!

Why do gurtner carb use a much smaller mainjet than dellorto carb in a standard yamaha aerox?

Dellorto to 2003 (86 jet)
Gurtner from 2004 upward (62 jet)
Is there a bigger inlet hole in the airbox or something in the previously models which requiring a bigger jet? Cant really understand why the jet sizes in a standard aerox is that different

 

It sounds to me as if the Dellorto is a 17mm carb and the Gurtner is a 12mm one. The jet sizes you quote are similar to those standard jet size for those carbs fitted to Peugeot scooters.

Peugeots take a Dellorto PHVA 17mm or a Gurtner PA360/PA370 12mm carb, depending on if the model. 50cc models would use a 12mm carb. the 17mm is used on the 100cc models.

The bigger jet would be needed in the Dellorto, to balance the fuel mixture for the higher air flow.

 

Thanks. But Im sure both is 12mm.. hmm strange.

 

i have wondered this myself, ive seen many different bikes, same setup, but with different jets.... i guess there is no reason why, its just how they work, could be to do with the emissions between those models, as i seem to recall the newer ones having a catalyser in the exhaust. the airbox and intake etc is the same on the older ones as the newer ones