GeoffreyLebowski

I took the decision to bite the bullet, and have sent the entire ignition system to Steve at Bradford windings for assessment and repair. When I spoke and mentioned the running backwards issue, he suggested that pointed towards the timing sensors. It was going to involve a 20 mile trip to find a suitable pull up resistor, and even if I had tested it, I then have the issue of where to go next regarding fixing it. If it was the hall effect sensors, sourcing them isn't easy and de-potting and replacing with my equipment looks tricky. If they are working fine then I have the issue of a new or refurbished cdi unit. Hopefully I'll have it back and running within a fortnight.

The woodruff key is still intact and undamaged.

Thanks Konrad, It has been 40 years since I did electronics at college or played around with circuits and I've forgotten most of it.. Could you explain how I can test whether the hall sensors are working correctly. I have looked at the data sheet for them, but am not really much wiser as to what I am looking for. I am presuming I could test on the bike and put a timing disc on the flywheel to monitor when the signal swithches. For the "early" trace; Do I put 5v on the black wire and measure the output from the blue wire via a 10k ohm "pull up" resistor? Turning the flywheel to monitor at what degree of rotation the signal switches. Presumably the applied voltage would be ok at about 7v ( a 6v dc battery charger)? What voltage would I expect to see on the output? the datasheet mentions 0.4 Vdc max. would it switch from 0.4 v to 0 v

Thanks Konrad. Some more useful information on understanding how the system operates. You may well be right about the wiring for the red green white plug, except that I think the ground is at one end of the two coils. If under a steady state resistance check, the coils approximate to resistors my deduction would be that the system is wired as my drawn diagram. Within experimental error, the resitances measured between the pins and the measurements from the pins to ground tally. Gn to ground 589 ohms R to ground 79 ohms W to ground 0.2 ohms

Konrad, Thanks for that info. I now know what is inside the pick up for the black, brown and blue wires. Did you use an oscilloscope to check for the early and late signal pulse traces? I checked my stator resistances and diode voltage checks with my stator in situ. I got the following results which I compared to the data on the on the splat shop site as follows. 3 way R W Gn connector: All well within limits R to W 78.5 ohms Spec. 50 - 100 ohms W to Gn 586 ohms Spec. 540 - 640 ohms Gn to R 509 ohms Spec. 450 - 550 ohms 3 way Bk Bn Bl connector: Readings slighly lower than spec. Diode check. Red lead to connector pin, Black lead to earth. Black lead to connector pin, Red lead to earth. Bn 919 mV Spec; 1000 - 1600 mV? 650 mV Spec; no data Bl OL Spec; no reading 648 mV Spec; no data Bk 911 mV Spec; 1050 - 1650 mV? 650 mV Spec; no data I also checked for ac voltages when kicking the bike over. Difficult to get a steady reading but both W to Gn, Gn to R and the single yellow wire were all indicating instantaneously between 3 and 20 V so presume they were suppling unregulated ac.

I'm hoping someone can offer some help on my Sherco 290 which has no spark. Last time out it was troublesome to start and kicked back an ran backwards a number of times which I haven't had before. I then got it running forwards, but when I stopped it to refuel I couldn't get it to restart. Checking the spark plug has shown there is no spark when I kick it. I Have checked over all the wiring and cleaned the contacts and earth points. I disconnected the engine kill switch to confirm it wasn't causing the issue. I have done some basic checks on the stator resistances and voltages and these seem to be within a spec I found on the splat shop website and an earlier topic. My ignition system is the Leonelli one, both the stator and the cdi unit. It is the one with the two 3 pin plugs and the seperate yellow ac wire. Unfortunately I don't know anyone with a similar system which I can interchange parts with. Is there any way of bench testing the leonelli cdi unit. I don't want to spend hundreds of pounds buying a new unit, or stator, only to find the problem is elsewhere.