about gst perpetual movement cal 79261

Hello Dear forum, i am hoping to find an perpetual calendar made by IWC, cose they are great and innovative, and i realy like the GST series. Sporty and steel with a high grade complication.

I hope you can help me with these 2 questions :
- can you increase the power reserve of the base valjoux 7750 ? maybe put in a larger spring in the barrel ?
- can you fast forward the complication if it has not been used for a couple of weeks by just turning the crown ? Or do you have to turn the crown and hour/minute hands for every day you want to advance the mechanism ? So like a norma watch with date complication ?

Thanks in advance !

I'm not an expert in watchmaking but:
[ol]
[li]A larger spring inside the movement wouldn't fit due to space limitation[/li]
[li]A larger spring inside the movement would change all the characteristics, so it would not work properly.[/li]
[/ol]
Don't try to do this!

There is a fast forwardoperated with the crown. That's one of the outstanding characteristics of this superbe complication made by IWC.
But be careful: There is no way turning back the date. So don't turn it over the current date, otherwise you have to wait for the set date to arrive without the watch running or to see a watchmaker who can adjust it.

Here is a download of the manual of the Big Pilot's watch perpetual calendar
The usage is just the same as with the GST Perpetual Calendar.

If you can find a GST perpetual this is one of the best value for money choices to find for this wonderful complication.

Thank you Tilo, for that complete answer ! I will read the manual you listed.