chunk t

Semple, you're a man after my own heart. Listen to Monty, he's got a good head on his shoulders (we've swapped a few PM's). Most of my mod'ing is for my boat engines & I've done some to car engines as well. What I've learned from others and self inflicted damage is... know exactly what you want to accomplish before you make your first cut and make sure you understand how that little two-stroke pump works.

Two suggestions I'll offer -
1. blue print the engine before you make your first change. You need to know your starting values for port timing (induction, transfer & boost, and exhaust), rod length, stroke, head bubble volume, head clearance, squishband area, head shimn thickness (if any), crank case volume, carb bore, port area & shape. it's a lot, but you need to know your stock numbers.
2. A cheap and effective way to give you hands-on cause and effect on a GOOD engine would be to pick up some head shims and sleeve shims. Swapping head & sleeve shims will allow you to alter the compression ratio, elevate exhaust, transfer & boost port timings. Adding & removing, individually or in combination will change the engine's performance. Head shims you can pick up at the LHS or an on-line hobby shop. Sleeve shims can be picked up on-line form Chris Wood at Wood's R/C Boat Products (woodrcboatproducts.com) these guys can make them cheep in an assortment of thicknesses.

& while your at it.. read up on how a tuned exhaust works. 'Cause once you begin changing sleeve timings you need to make adjustments to the pipe &/or header length.

But it's all in the name of fun.