Fuel and Air/Intake

Yamaha RD250/350/400 Reed Block Spacers Billet, Plain (pair). Machined from 6063 T6 billet aluminum. These spacers are 9mm thick. Why Reed Spacers? Basically, reed spacers allow you to move your power band around depending on placement. The most common installation for street use is to mount them between the reed block cage and the engine. This will effectively increase crankcase volume and move your power band to a lower rev range, allowing you to make better use of the power available for street riding. The second type of installation is to mount them between the manifold and the reed block cage, increasing the intake tract. This will move the manifold back further and raise the power band for better midrange and top end. Individual results will vary from bike to bike depending on intake set up, air filters, jetting, porting, exhaust, etc. We also carry new RD/RZ manifolds, both the regular stock RD manifolds and RZ manifolds with cross over tube. Stainless or black manifold Allen (cap socket) bolts available in longer lengths to accommodate these spacers (in the bolt kit category). Not recommended for use with stock air box). Choose model and click add to cart.