Yes it possible to fit larger amp batteries as long as same diamentions as old 1's I fitted 12amp to grandsons Oset and charger would be ok also.try E bay for purchase.
Also the Stators fail,saying that iv'e had 3 and had no problems,rear shock can be rebuilt by Andy Dawson if need be.had to have my rear done,and what a difference it made.
It is a narrow single road.up to the Venue but you should be ok tight turn in to the parking area.I should try and get there early if possible not the largest parking area.
Or could fit 1 of these https://www.ebay.co.uk/itm/MOTOCROSS-QUAD-BIKE-FUEL-CAP-PETROL-TANK-one-way-BREATHER-PIPE-HOSE-CRF-KTM/152293434767?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D46150%26meid%3Db2afd59935274b40982f028eb4255dfe%26pid%3D100005%26rk%3D1%26rkt%3D6%26mehot%3Dpp%26sd%3D352134780433&_trksid=p2047675.c100005.m1851 Trials znd MotorCross nearly double price lol
There's this set on E Bay. normally about 33inch wide https://www.ebay.co.uk/itm/Renthal-Trials-6inch-rise-7-8-22mm-handlebars/112618530916?hash=item1a38966864:g:V7IAAOSwj99Z6OWD or these https://www.ebay.co.uk/itm/RENTHAL-TRIALS-HANDLE-BARS-5-6-RISE/272897434611?hash=item3f89f463f3:g:KMMAAOSwvZVZnEnp if you don't want to wait.