Over the past few months I stripped my Yamaha TDR250 down to bits and did a complete mechanical rebuild. This included powdercoating the frame, rebuilding the crank, new pistons and con-rods, reconditioning the suspension, powervalves, oil pump and carbs, sealing the tank and repairing the speedo. I didn’t paint the rest as it still looks OK.
Everything works except that there seems to be a problem with the ignition and powervalve control. The valve cleaning circuit works and all the ancillary electrics are fine so I suspect the CDI/ECU.
Do you know where I can get one or suggest how to go about opening it up. Perhaps it’s dry joints on the circuit board. Neither the agents nor Yambits can help me. Johan Engelbrecht, South Africa
Ferret says: Before suspecting the CDI, check the resistance of the exciter and pulser coils in the stator as faults in these will prevent a spark despite everything else apparently being alright. Make sure everything that needs an earth is making good contact and not being insulated by your new powdercoating. If that all fails borrow a known good box to try on the bike. After that, your best option is a replacement system from the likes of Zeeltronic.