Before a Rebuild February 20, 2013, 04:57:02 pm More good info from Sicivicdude. He posted this in a thread and I am just sharing it with everyone here....... Quote from: sicivicdude on February 20, 2013, 02:25:26 pmAlright, the same advice I would give anyone before they start ANY build (go-kart to jet airplane!). Determine your ultimate power goals and most likely use before buying anything or doing any mods. If you are going to be trail riding, your build is going to be vastly different than if you are going to be hillshooting. Some "go fast" parts are good "investments" power to money wise. Others are VERY poor investments power to money wise. Good investments include porting, head mods, pipes, (sometimes) carburetors, aftermarket air filters, good clutch kits, and good tires. Bad investments include "go fast" parts that aren't really go fast as much as they are bling fast. Examples would be billet aluminum intake manifolds, aftermarket reed blocks, hi flow water pump impellers (the stock impeller flows PLENTY for all but the highest end drag bikes), and generally other chrome and polished goodies. I'm not saying that chrome and polished goodies don't have their place. Only that if you're trying to squeeze the most bang for the buck, chrome and polished goodies can be left off the tab without hurting your power and performance. If you're building a stock stroke stock bore banshee you plan on just RIDING instead of racing. Forget the 2 into 1 manifold, forget the PWK carburetor/s, forget the VF3/4's (unless you get a set CHEAP second hand), coolhead and domes, and hi flow impeller. The high output coil is optional. If you're staying gasoline on a trail bike, you can keep your eyes open for someone selling a PVL or nology dual outlet 1.6 ohm coil but the stock one also works quite well for that application. Stick with the stock carburetors. As surf said, two VM26's can handle a lot of engine before they HAVE to be changed. Get a pair of boyesen dual stage reeds for the stock reed cages. You won't be pulling more air through the stock reed cages than they can handle, anyway! Forget the cool head and 22cc domes. That's basically a stock head combustion chamber wise and you're going to be running a trail bike, the head isn't going to overheat anyway. If you want to bump up the compression some, you can just get a stock head cut and save about half the cost of the coolhead. The hi flow water pump impeller is hiding a secret.... they don't actually take away any more heat than a stock one. The heat generated by the engine is all that will need to removed anyway. The stock cooling system can handle WAY more heat than the engine is going to generate at a normal tune level. What "hi flow" impellers actually are is a slightly tweaked design that makes them less likely to cavitate at higher rpm's. On a drag bike, the engine is going to operate at an EXTREMELY high rpm for a short period of time. In that same period of time it's going to generate an enormous amount of heat that will need to be dealt with. The stock impeller is designed to be efficient at a maximum rpm much lower than the operational rpm of a dragbike. The stock impeller would cavitate (create tiny air bubbles and air lock) at the rpm the engines operate at so they use a "hi flow" impeller that is designed to operate at those high rpm's without air locking.