Hello and thanks for reading, I have recently built a crf450r with a hegar jackshaft. Everything in the motor is new from piston to electronics. Stater, coil, plug, plug wire, cdi box, all brand new. I have not replaced harness due to the fact that every wire has been tested multiple times by me and my father, and every wire has continuity. Also coil is grounded directly to the motor with a 12 awg solid copper wire. And motor mount is grounded to the frame. I have tested two other spark plugs and have also ohmed the stater and coil. I am completely at a loss. I cannot achieve spark. The pictures are of me in a high state of stress so dont mind the mess also I've pulled all the tape off the wires to check for any bad places. View attachment 14429
No spark crf450r
- Thread starter Hoonigan
- Start date
flattop1
Dawg 89
this could be true . I remember seeing something along those lines from One of the UAS guys .
Compu-kart
Member
^^^^ YES ^^^^
Some of the Selectra coils were 'closed loop grounds' and therefore when you put a ground wire on them, they would not fire (because it also grounded the primary side of the coil). A lot of the Jawa engines had this ignition and it was probably the first problem every Jawa owner experienced. All you had to do was float the coil mounting and the problem disappeared. I'm not sure that the motorcycle engines are the same, but it's easy to check. I lean towards Jimbo's response. It sounds more like a weak pickup sensor.
Jimbo
You can fool some of the people some of the time
Although most of the time an ohmmeter works for testing ignition parts it is not the best..
The crank sensors are best tested with a lab scope (if you know how to use one) or at the least with a conventional digital volt meter.
The crank sensors are best tested with a lab scope (if you know how to use one) or at the least with a conventional digital volt meter.
| Part | Specification |
| Spark Plug | |
| – Standard (NGK) | SILMAR9A-9S |
| – Optional (NGK) | SILMAR10A-9S |
| Spark Plug Gap | 0.9-0.9 mm (0.03-0.04 in) |
| Ignition Coil Resistance (@ 68°F/20°C) | 2.6 – 3.2 Ω |
| Ignition Coil Peak Voltage | 100 V minimum |
| CKP Sensor Peak Voltage | 0.7 V minimum |
| Alternator Coil Resistance (@ 68°F/20°C) | 0.1 – 1.0 Ω |
| Ignition Timing (“F” Mark) | 8° BTDC @ idle |
| Alternator Capacity | 0.091 kw/5,000 RPM |
Jimbo
You can fool some of the people some of the time
I found this on https://thumpertalk.com/forums/topic/550295-crf-450-no-spark/
"Okay I have found another solution to the problem. I took in some work on a friends bike with adjusting the valves and carb work. So I disconneted all of the wires around the carb which includes the main wiring harness. Finished it all up connected everything up and then you guessed it NO SPARK!!!! After doing what everyone else on here has done. By taking a donor working 450 I checked the CDI, Coil, and Spark Plug etc, I call my friend which put a aftermarket stator for his lighting kit to find the problem. Electro-Sports Stators are JACKED UP. Throw common sense out the window on this one. Most of us would connect like colors together on the wiring harness. haha. Not these guys aftermarket stator. Blue Wire to White Wire, White Wire to Blue Wire, Blue/Yellow to Blue/Yellow, Green to Green/White. Switch the Blue and White wires and then PROBLEM SOLVED!!!!"
"Okay I have found another solution to the problem. I took in some work on a friends bike with adjusting the valves and carb work. So I disconneted all of the wires around the carb which includes the main wiring harness. Finished it all up connected everything up and then you guessed it NO SPARK!!!! After doing what everyone else on here has done. By taking a donor working 450 I checked the CDI, Coil, and Spark Plug etc, I call my friend which put a aftermarket stator for his lighting kit to find the problem. Electro-Sports Stators are JACKED UP. Throw common sense out the window on this one. Most of us would connect like colors together on the wiring harness. haha. Not these guys aftermarket stator. Blue Wire to White Wire, White Wire to Blue Wire, Blue/Yellow to Blue/Yellow, Green to Green/White. Switch the Blue and White wires and then PROBLEM SOLVED!!!!"
Last night actually yes..we replaced the new stator with the old and it fired...although the new stator was new and checked out ohm wise. The new stators pickup was somehow not close enough to the flywheel...but the problem is solved and now we can get on with building this badass machine. Thank you to all who helped. Good luck to you and yours this racing season!!!
Thanks
DRM Racing
Thanks
DRM Racing
