i have an 2003 400ex and wanted to do an engine switch. I was hoping to a switch of a four stroke dirt bike. like yff 450, crf 450 etc..
If anyone has any experience in this i would like to know which is the easiest to awitch into a 400ex or what modifications i would need to do to switch the engine, also with the type of engine.

thanks

 

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sry had to edit it pendejo

 

i thought about finding a wrecked 600cc croutch rocket and doin an engine swap what u think