The maximum utility category weight for the -9's is 1600lbs, with the maximum gross weight recommended being 1750lbs.
It is irrespective of engine size, though with a smaller - lighter - engine you have a higher payload before hitting either of those limits, while still achieving 900FPM climb at max gross.
In some jurisdictions the MTOW may be limited by legislation, ie mine is currently limited to 1320Lbs MTOW until I can get it re-registered with CAsA.
Once you have tasted flight you will forever walk the earth with your eyes turned skywards, for there you have been and there you will long to return - Leonardo DaVinci
My Flickr gallery: http://www.flickr.com/photos/35521362@N06/
RV-9A 19-8519 - Finished on 10th February 2016 after 4 years, 9 months and 19 days! The 1020th RV-9 flying.
First flight 26th March 2016. Phase I done. Essential specs 145KTAS @ 2400RPM, 8000', 24.2LPH, Initial RoC 1800FPM.