Hi, my 16 yr old son has recently bought a very nice 01 CR250, virtually everything rebuilt including the engine,it's got a VHM race head,HGS pipe and by the way it rides maybe had a bit of porting done. It's the bike he's always fancied(and sold his CRF250 to buy it), however, it's a bit too much bike for the fun riding and trail riding he does so we want to detune it or 'mellow' it a bit. After reading quite a bit on here and in Eric Gorrs book here is a list of things we plan on doing, if anyone has first hand experience of these mods ,or know of any other mods to increase the low to mid torque and rideability I would appreciate you sharing the info. Lower the cylinder barrel with a thin base gasket,I'm thinking about .5mm lower,how does that sound? Fit a thicker headgasket to compensate for the thinner base gasket and to lower the compression ratio. Make a 1/2" thick ali spacer to fit under the exhaust valve resonance chamber. Turn up a flywheel weight around 13 oz to fit onto the generator rotor. Fit a shorter rear can(opposite to what I know,longer pipes normally increase low end torque in the V8 engines I play with). Advance the ignition timing a couple of degrees. Re-jet the carb,which is a Keihin. Fit a one step hotter plug. We will also look into epoxying the rear transfer ports as touched on in Gorrs book,aiming them at each other instead of at the exhaust port. Anyone have an idea how much to narrow them by,and is this done just at the ports exits? What we are trying to achieve is a bike that is as easy to ride as his CRF250 was,we are not concerned with losing top end power as long as the low to mid power is smooth. Actually doing the above mods is not a problem,I'm quite conversant with engine tuning, what I need to know is if the work will actually improve the bike in the direction we want. Thanks. please,no sell the CR and buy another CRF type answers!