Righty-o

I measured the TRX engine and compared it to the FZR engine. The TRX engine is 30mm or so narrower across the cam cover but 10mm taller from the bottom of the case to the very top of the cam cover. The TRX rear engine mount is 200mm across. The distance from the crank end to the swingarm spindle centre is the same on both engines and the distance from the swingarm spindle to the rear engine mount is 5mm longer on the TRX. The oil tank on the TRX will fit the 3EN1 frame but there's not a lot of room for any kind of fuel tank

So... I think it'll go but I'm not going to try it!

Ta for doing that, i'll get my scrapbook and crayons out and start scribbling some "plans"

Where in the world are you Nick? You're more than welcome to pop round and try a 3TJ frame around the TRX engine. I'm in the North East.

Down 'sarf in Essex, well below the watford gap

Ta for the offer though, if i was closer then i'd have said yes please