ER5 engine into GPZ

pompousporcup... · World Chat Champion Joined: 15 Apr 2015 Karma :

Posted this over on ex-500 too, hopefully the likes of stinkwheel/kickstart would know the answer.

I've had a bit of a mishap with the GPZ engine (see other post). Now i've ordered a replacement starter sprocket which i am hoping sorts it for a while but will need to swap the flywheel out for a revised version. I have found a pattern part for about the same price as a full ER5 engine. Given that a newer ER5 engine is likely to be more reliable than my 20something old GPZ engine, i've been toying with the idea of just going for the swap as an excercise in reliability for the old bike

So. ER5 engine into a GPZ frame, ER5 jetting into the GPZ carbs (or stock GPZ carbs, although it might run too rich?) and stock GPZ ignition.

Has anybody done this before? I'm guessing i'd have to mod the flywheel on the ER5 to get the single point the GPZ system is expecting or is it not that simples.?

Any other reasons this wouldn't work?