I checked the voltage on what I assumend was the main power carrieing signal going from the CDI unit to the servo (white cable with red stripe connected via single spear connector separate from the other 4 cables going to the servo geatherd in the separate connector) the voltage on the calbe measured about 2.4 volts when connected to the servo and about 4.2 volts when servo is disconnected (all DC). No changes to the voltage were noteced as I reved the motor up and down the votage staid constant about 2.4 volts. Is this normal?
SRX7
New member
You know what I would do my friend ( I know you sent me a PM ) but go and see if 800 will let you used his used one from his sled and test it. Even Bruce from CB performance said he wouldn't mind.
Check you thread about buying a CDI........
It's worth a shot, this is going to drive you nuts.....
Check you thread about buying a CDI........
It's worth a shot, this is going to drive you nuts.....
I spoke with 800 today he said he doesn't have any other computers laing around but this one, unfortenatelly.
SRX7
New member
Hey you tried......
you need to check the voltage cold ,then warm up the sled till it acts up as you describe and check the voltage drop, this will tell you if its the cdi box, if the signal is lower its the box breaking down.
Thank You
Firs of all I would like to thank everyone who was helping me work on this sled by sharing the knowledge. I wouldn’t be able to do it without you, THANK YOU. In the schematics diagram it shows that the wires on the test lead both end up in the CDI box (not counting the ground wire). From my knowledge of electronics I assume that one will carry the power to the CDI box and another wire will carry the control signal that will tell the CDI to open the PV. Since the servo motor gets its input from the CDI which in tern monitors the RPMs I followed (on the diagram) the test lead and sure enough it was connected to the DC rectifier. The tachometer signal was connected to the same wire as the test lead (DC rectifier). My RPM gage works fine that means that the DC rectifier works fine and so does the coil. I checked all connecters for continuity and they all checked out fine. Since the servo was kind of working I bet on the servo being fine as well. Another thing that kind of made me lean more towards the faulty CDI is that the temperature light was working time to time or not working at all (I check out the continuity between all connectors they were fine). Well I got the new CDI today (thanks “800”) connected it, servo and temp light are working the way they supposed to. Now the fun part “the way I broke my CDI” by connecting both test leads to 12V I powered the CDI with one lead (which is fine) but the second lead supposed to simulate the control voltage from DC rectifier (magneto eventually) into the CDI was carrying way to much voltage (12V). When the RPM’s go above 6500 (PV fully open) the input voltage to the CDI from the rectifier is below 12V!! The real test lead that supposed to be used has a big resistor on the wire that connects to the CDI control signal. The resistor drops the 12V to appropriate reading accepted by the CDI (I wish I knew this before or at least the schematics would show that). The reason that my “homemade test leads” didn’t smoke the DC rectifier or the coil is because of the rectifier design (rectifiers have a special circuit which is called a diode bridge that prevents the voltage leak to the AC side of the circuit). As far as my explanation for the servo acting fine when the sled is cold and stop working as soon as the sled heated up (with old CDI) here is what I think might have happened. When I connected the “homemade test leads” to the control signal input to the CDI unlimited 12V damaged the CDI box (possibly a short) BUT the voltage didn’t damage it all the way. When the CDI box was cold there was enough insulation to keep the servo working (possibly on the CDI circuit board). As soon as the sled warmed up (CDI unit carrying electrical signals warmed up as well, just from carrying the signals like your TV at home or computer). The damaged insulation within the CDI stopped insulating and servo stopped working. HANGING RPMs were fixed by adjusting the fuel screw on the carbs to 2.5 turns. Now all I need is SNOW!!!!
Firs of all I would like to thank everyone who was helping me work on this sled by sharing the knowledge. I wouldn’t be able to do it without you, THANK YOU. In the schematics diagram it shows that the wires on the test lead both end up in the CDI box (not counting the ground wire). From my knowledge of electronics I assume that one will carry the power to the CDI box and another wire will carry the control signal that will tell the CDI to open the PV. Since the servo motor gets its input from the CDI which in tern monitors the RPMs I followed (on the diagram) the test lead and sure enough it was connected to the DC rectifier. The tachometer signal was connected to the same wire as the test lead (DC rectifier). My RPM gage works fine that means that the DC rectifier works fine and so does the coil. I checked all connecters for continuity and they all checked out fine. Since the servo was kind of working I bet on the servo being fine as well. Another thing that kind of made me lean more towards the faulty CDI is that the temperature light was working time to time or not working at all (I check out the continuity between all connectors they were fine). Well I got the new CDI today (thanks “800”) connected it, servo and temp light are working the way they supposed to. Now the fun part “the way I broke my CDI” by connecting both test leads to 12V I powered the CDI with one lead (which is fine) but the second lead supposed to simulate the control voltage from DC rectifier (magneto eventually) into the CDI was carrying way to much voltage (12V). When the RPM’s go above 6500 (PV fully open) the input voltage to the CDI from the rectifier is below 12V!! The real test lead that supposed to be used has a big resistor on the wire that connects to the CDI control signal. The resistor drops the 12V to appropriate reading accepted by the CDI (I wish I knew this before or at least the schematics would show that). The reason that my “homemade test leads” didn’t smoke the DC rectifier or the coil is because of the rectifier design (rectifiers have a special circuit which is called a diode bridge that prevents the voltage leak to the AC side of the circuit). As far as my explanation for the servo acting fine when the sled is cold and stop working as soon as the sled heated up (with old CDI) here is what I think might have happened. When I connected the “homemade test leads” to the control signal input to the CDI unlimited 12V damaged the CDI box (possibly a short) BUT the voltage didn’t damage it all the way. When the CDI box was cold there was enough insulation to keep the servo working (possibly on the CDI circuit board). As soon as the sled warmed up (CDI unit carrying electrical signals warmed up as well, just from carrying the signals like your TV at home or computer). The damaged insulation within the CDI stopped insulating and servo stopped working. HANGING RPMs were fixed by adjusting the fuel screw on the carbs to 2.5 turns. Now all I need is SNOW!!!!
9801srx
Member
good to hear you figered it out, thats what i thought happenen ,the resistor is very important part of the coupler .
SRX7
New member
Note to self. Lower rpm's instead of test leads. LOL
Now that I know it's defeatelly will be my chose. Just got back from riding (after the valves got fixed and screw adjusted to 2.5) I almost SH..T myself this thing is a BEAST I don't think I can rid it around Wauconda anymore, THERE IS JUST NOT ENOUGH ROOM. I think I will readjust the screw setting to 1.75-2 the exhaust smelss like unburned gas to much and the smoke is a bit white.