The bike in question is stock except for manual cam tensioner and aftermarket slip on I know the bike is old now but I wanted a blue bill 351 kit however it was going to cost 1700AUD to get it over here and a decent carburettor that isn't a cv one is around another $200, my dollar savvy self has noticed the $400 kits available on Amazon but I am not all that keen on it blowing up.

So the issue is sell and upgrade or fork out 2 grand and then try do the work myself..

Any help appreciated

 

There was a post in the ADVriders KLX250 or one of the KLX300 threads about a big bore from Thailand. I have to think from Thailand it might be better money for you if you can find out what the company is.

A number of riders have done the 399cc AHL kit (not the 292cc). It was under $200 usd on Amazon.