I have G2 forks here on a RB G2 bike that measure 23" from the top of the tripple to the ctr axle with the bike sitting level. I beilieve your +1 forks measure 21" so you might be a couple inches short in the front? Hope this helps?
Better yet go with a set of crf 70 forks/clamps they measure out to be 22" and should fit right on. You should be able to pick some up at a reasonable price 100.00/125.00?