Yamaha SX700 - 1997
Last season I got a serious ignition problem on my sled. I checked coils, caps, wiring, flywheel and stator. The stator was broken due too way to high resistance in the spark plug caps (25kohm and above).
I rewinded the stator myself and the sled ran well for 500km and then the stator broke again. Rewinded it again and the sled ran for 30km until it broke a second time. I gave up the idea to rewind it a third time and bought a new stator.
Now to my problem. With the new stator (stock and same part number) I got something wrong with the ignition-time (too late ignition). The exhaust pipe nearly starts to glow sometimes due to the high temperature and the engine misfires and throws fireballs from the exhaust pipe on low rpm but runs well on higher rpm. The cooling fluid have normal temperature.
Have checked coils, wires, plug caps, cable harness, flywheel and the stator once more and everything seems to be oki. The flywheel is correctly mounted and cleaned.
Can a bad CDI-unit cause this? Are there any way to correct the ignition advance? Got a stroboscope-light but don't know what the markings on the flywheel means.
Would be very thankful if anyone could help me out with this. Have no ideas left more.
Last season I got a serious ignition problem on my sled. I checked coils, caps, wiring, flywheel and stator. The stator was broken due too way to high resistance in the spark plug caps (25kohm and above).
I rewinded the stator myself and the sled ran well for 500km and then the stator broke again. Rewinded it again and the sled ran for 30km until it broke a second time. I gave up the idea to rewind it a third time and bought a new stator.
Now to my problem. With the new stator (stock and same part number) I got something wrong with the ignition-time (too late ignition). The exhaust pipe nearly starts to glow sometimes due to the high temperature and the engine misfires and throws fireballs from the exhaust pipe on low rpm but runs well on higher rpm. The cooling fluid have normal temperature.
Have checked coils, wires, plug caps, cable harness, flywheel and the stator once more and everything seems to be oki. The flywheel is correctly mounted and cleaned.
Can a bad CDI-unit cause this? Are there any way to correct the ignition advance? Got a stroboscope-light but don't know what the markings on the flywheel means.
Would be very thankful if anyone could help me out with this. Have no ideas left more.
tedgoesfast
New member
ive seen a new stator bad before
I have hard to believe that the stator is bad. It's not an new one, it came from a working sled. I'm 100% sure that the stator worked in that engine. How can a bad stator affect the timing of the ignition? I've only heard of problem with bad spark or no spark at all with a bad stator.
jet101ski
New member
You have two parts to the stator, charging coils ( thats the one with all the windings) and the pickup coil ( thats the little black sensor). The charging coils only make electricty, the pickup coil controls timing. I have seen about 50 pick up coils fail! normally its the wire coming out of the pickup coil has a crack inside the insulation. Check there. If its ok your cdi is bad! I have seen that also!
I've just checked the pickup coil. No sign of wear on the cables near the coil. Measured the resistance and it was 203Ohm which seems to be ok according to the workshop manual. Measured the pickup coil on my old stator and it was 205Ohm so I believe that the there's some other problem than the pickup coil.
Any other suggestions besides getting a new cdi-unit?
Any other suggestions besides getting a new cdi-unit?
it might be a plug,,,,try pulling the plug wires off one at a time while its running to make sure all cylinders are fireing.
Problem solved for now! Replaced the spark plugs with new BR9ES and disconnected the TORS. Took it for a hard ride for about an hour in -20C and no misfires and normal exhaust temperature. Don't know if it were the sparks or TORS which caused the strange problem but I guess it was the second one.
Thanks for your replies, a really great forum!
Thanks for your replies, a really great forum!