I'm going to get the 444 crosser engines pipes made to peak at 10500 rpm which is 800 rpm higher than the 475 (big bore standard barrel) engine. The crosser barrel gives better power & torque throughout the rev range than the standard engine so even with 33cc less at 444 should put out as much as the 475 engine, with the same sort of curve and the extra revs at the top end 90bhp should be achievable.

The 250 with the standard bore of 56mm makes 54bhp so add another cylinder + 27bhp equals an 81bhp 375cc engine so with another 69cc (+18% more cc) should give around 10% more power which would be 88 / 90bhp. The 250 engines barrels are very mildly tuned and the pipes are not custom made for the engine (damaged RGV250 race pipes off Ebay for £40) so custom pipes and a higher state of tune together with what I learnt whilst building the 250 engine should go in my favour, fingers crossed with the triple !

Cheers Ian