My 2003 yamaha blaster won't fire, it fires once then stops. I replaced coil, cdi, plug, magneto, and got it timed right but still nothing. I lost the key and unplugged the keystart would that make it not start? Please help!!

Just a thought without looking at it but could be loose wires involved with the coil. Bad coil wire.[burnt or worn on inside] Can you see spark jumping from pug wire. If so try tape on wire, and if that helps ,replace wire ,and coil if inseparable. Also check wiring coming from magneto, points or cdi . Electrics are the mechanics worst problem to solve.

I have 2002 road star midnight. I lost completely spark on all 4 spark plugs. Before bike was running OK but sometimes on low RPM while idling would skip a firing on a at least one cylinder making spufff like sound. I put new spark plugs, and wiggled a little coil wires. Bike with new spurk plugs would not fire up at all. Checked for spark on all 4 spark plugs - no spark., not even an electrical I lost completely spark on all 4 spark plugs. Before bike was running OK but sometimes on low RPM while idling would skip a firing on a at least one cylinder making spufff like sound. I put new spark plugs, and wiggled a little coil wires. Bike with new spark plugs would not fire up at all. Checked for spark on all 4 spark plugs - no spark., not even an electrical charge going to spark plug. Went back to coils. Each coil (there 2 of them) has 2 spark plug wires and 2 ignition timing signal wires connected to them. I realized that these ignition timing wires contacts are corroded to the point they would not conduct a charge from the distributor to coil. CLEAN ALL THE TIMING WIRES Contacts on the coils. I did that and bike fired up right away and started running much better without sputtering or skipping a cylinder firing. SO DISCONNECT ALL THE COIL WIRES AND BRUSH THE CONTACTS WITH A SMALL METAL WIRE BRUSH.

Black is ground
Black / Red is CDI charging coil-- 240 ohms
White / Red is CDI pulser coil-- 20 ohms
Yellow is lights-- less than 1 ohm

Check the points for proper gap and clean. The old school bikes used more than just coil and plugs. Also, often overlooked, check the kill switch connection. Often this is the case on Yamahas.

check your pickup coil?

check your coil,cdi,magneto( i would check them in that order)

89 Katana uses two coils, one fires cylinders 1 and 4 together and the other fires 2 and 3 together. It's a waste spark system. So your firing order is either one coil or the other every revolution.

take magneto cover off find tdc on the magneto and look at the cams it should be after the inlet valve shuts and goes on the firing stroke just put a rod in the cylinder and see if the piston reaches the top off the bore when the magneto is at tdc then its fine buddy any probz im here to answer

follow the plug wire back to the coil and see if there are any breaks, if not might switch coil with the other one and see if the other plug now misfires, if so replace the coil, most cdi problems are not intermittent, typically they either work, or they dont.