i put the fmf pipe on my blaster and never jetted it. will this cause problems . and what exactly is jetting it mean and do

 

Yes, you need to jet it........Both for better performance and longer engine life. With stock jetting and your FMF, the engine is running too lean. A larger main jet will increase fuel to the added air your engine is now moving. Running with the stock jetting can cause, a burnt piston, stuck/melted rings, blown head gasket, and not to mention a ton of money. Don't waste money on a "jet kit". Contact FMF and get a baseline jetting recomendation. Then, go your local Motorcycle/ATV shop to purchase the new jets (around $4 each). Consider installing a pro design filter setup to fix Yamaha's horrible airbox design and keep the engine clean. Hope this helps!