Crofty Posted March 29, 2009 Report Share Posted March 29, 2009 Hi, I need some help getting my RG250 Mklll running after a long rebuild. It started twice for about a second, now has no spark. I suspect the CDi but cant grasp the method of testing it! If I unplug the CDi I get what appears to be an alternating current at the Green and Black/Red wire...the meter needles goes the wrong way, hits the stop, than flicks across to positive voltage. Now the confusing bit is if I unplug the Power Valve Servo, I get 8 Volts at the Red/White to the CDi! Any help wud be most appreciated as its been 18 Months in the making, this thing! Oh, and one note, it looks like there may be a mis print on the wire diagram!! At the CDI Green and Black/Yellow I believe are mixed up! Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 29, 2009 Report Share Posted March 29, 2009 CDI testing is very hard with a multimeter check the stator resistances and check if you've got voltage to the HT coil check the ignition coils and the pulser coil If these check out then CDI is suspect Best method is to swap with a known good one Link to comment Share on other sites More sharing options...
Crofty Posted March 29, 2009 Author Report Share Posted March 29, 2009 No Volts to the coil..... Black/Yellow is deader than a dead thing. Link to comment Share on other sites More sharing options...
spacemonkey Posted March 29, 2009 Report Share Posted March 29, 2009 No Volts to the coil..... Black/Yellow is deader than a dead thing. If I remember correctly the RG workshop manual has a load of info on testing the CDI..... Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 30, 2009 Report Share Posted March 30, 2009 No Volts to the coil..... Black/Yellow is deader than a dead thing. Do you have correct Stator resistances? Also check if the stator is producing voltage when you kick it over, from both the source coil and the pulser coil If so, then assuming you've not got it switched of, then it is looking very likely to be the CDI Link to comment Share on other sites More sharing options...
Crofty Posted March 30, 2009 Author Report Share Posted March 30, 2009 At the CDI, I can detect voltage at both the Green and the Red/Black when its kicked. The manual has masses of info re testing the Generator, the Power Valve Servo and Control Module, but nothing for the CDI. Resistances I will check tonight and make use of the extra hour of daylight!! Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 30, 2009 Report Share Posted March 30, 2009 Green and Black/Red look like low and high speed source coils what about voltage from the R/W wire (pulser coil)? Link to comment Share on other sites More sharing options...
Crofty Posted March 30, 2009 Author Report Share Posted March 30, 2009 The Suzuki gives values for checking the ignition coils, but goes on to say that using a none Suzuki meter will give different results!! But THIS different?? R/W > B/W Spec = 4000 to 7000 Ohms Reading is 100 Ohms G > B/W Spec = 19 to 29 kOhms Reading is 9 Ohms B/R > G Spec = 500 to 1500 Ohms Reading is 9 Ohms Now, the Red/White wire is dead,even when kicking the engine over, however, if I unplug the 3 wire plug to the Genny, the R/W now shows about 4 Volts (and the Neutral Light Dims) and if I also unplug the CDI I have full battery voltage here. That I don't understand. Your time is really appreciated here. Checked out the resistance readings on the regulator, coz of the above mentioned difference, and they were miles off Suzukis specs, too....kind of renders manual figures redundant!! Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 31, 2009 Report Share Posted March 31, 2009 Unplug the stator completely to test it (if you havent in the above post), then re-post resistance values for the source (both high and low speed) and the pulser coil Also confirm if they produce AC voltage when kicking it over Link to comment Share on other sites More sharing options...
Crofty Posted March 31, 2009 Author Report Share Posted March 31, 2009 The above values are with the stator unplugged. You know I mentioned I had volts out of the Red/White wire if I unplugged the stator? Well the cause is the Temp Sensor. If I unplug ALL of the engine wiring, leaving just the temp gauge, the WHOLE BIKE IS LIVE, to the tune of 8 Volts!!! Now I know the votage from the temp gauge has no earth if the engine loom if unplugged, but is it really normal for the temp sensor to do this?? The gauge works OK, if I ground the Sender wire, the gauge reads HOT, as per normal. I,m guessing the sensor is FUBAR'd? If I kick the engine over, no signal is detected out the Red/White wire. Isn't this the trigger for the CDI? G > B/W is now 200 Ohms with the Temp Sensor un plugged!! Thank you again. Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 31, 2009 Report Share Posted March 31, 2009 very strange about the temp sender - all it is, is a variable resistor that changes value with heat dunno what to say about that, at the moment Lets just do the ignition first, as it is a totally seperate circuit Yes - the r/w wire is the pulser coil, and it triggers the CDI to fire every engine revolution So you are saying the manual says R/W to earth should be 4 - 7K ohms but you've got 100ohms, and you've got not no AC voltage out of it when you kick it over - correct sounds like you got a short - check the wiring all the way back to the pulser coil Also check the gap between the pulser coil and the rotor - it has to be pretty close to 'see' the magnet Normally they burn out when they fail and show open circuit ie infinity Link to comment Share on other sites More sharing options...
Crofty Posted March 31, 2009 Author Report Share Posted March 31, 2009 Hmmmm, I've unplugged the Red/White and have no resistance between the red/white wire from the pick up and earth. I've unscrewed the pick up from the crank case, and its open circuit again, so there's no short in the wire. The pick-up is as close to the rotor as its screw slots will allow, and still generates no signal to the CDI. Could the engine becoming live off the temp sensor have killed the pick up or CDI? Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted March 31, 2009 Report Share Posted March 31, 2009 Hmmmm, I've unplugged the Red/White and have no resistance between the red/white wire from the pick up and earth. I've unscrewed the pick up from the crank case, and its open circuit again, so there's no short in the wire. The pick-up is as close to the rotor as its screw slots will allow, and still generates no signal to the CDI. Could the engine becoming live off the temp sensor have killed the pick up or CDI? Is it open circuit (infinity resistance) or shorted (zero resistance/ continuity) ? Link to comment Share on other sites More sharing options...
Crofty Posted March 31, 2009 Author Report Share Posted March 31, 2009 I connected the Ohm meter between the battery NEG and the unplugged connector to the pick up, there was no resistance what so ever. Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted April 1, 2009 Report Share Posted April 1, 2009 You have a short then, hence no trigger to the CDI to fire Link to comment Share on other sites More sharing options...
Crofty Posted April 1, 2009 Author Report Share Posted April 1, 2009 Thanks....maybe getting somewhere now? By short, do you reckon its a faulty pick up?? The wire itself is not grounding, I've checked that. £50.00 quid to get the pick up replaced..... Thanks for taking the time to help, ur a top man. Gary Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted April 1, 2009 Report Share Posted April 1, 2009 Yeah sounds like an internal short the resistance readings should be in the ball park of the figures quoted in the manual, so if its supposed to be 4K to 7K ohms and you've got 0 ohms then its knackered if you're sure it ain't a grounded wire from the insulation worn through etc They normally go open circuit due to burning out If that still don't sort it out, then PM me if your struggling I knew all those years of messing with two strokes would prove useful someday Link to comment Share on other sites More sharing options...
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