fat kiwi

Hopefully you’re all sorted now. Just a quick update on the Leonelli stator repair. The twin trigger circuit is really basic. To completely rebuild it like new you need 2 SS543AT Hall effect sensors (eBay/Amazon), two 22uF capacitors, some epoxy glue and a small soldering iron. Dig out the old epoxy with a knife, replace faulty item(s), test using Splatshop’s ohm/diode values guide on their website. If ok - reseal with epoxy and enjoy. Took me about an hour to do- cost a tenner. Bike started first kick and learnt a fair bit about ignition timing in the process. Hope this helps if it happens again.

Hi. That’s a strange problem. I would suggest measuring the protruding end of the crank shaft that the magneto flywheel attaches to. I can measure mine tomorrow and see if it’s the same. If not, I’d crack the cases open and have a look at what’s going on. I’ve completely rebuilt 2 of these engines without any problems apart from removing the seized in swing arm bolt (I’m an electrician and not particularly mechanical minded). Parts from Splatshop and the rebuild guide from Ryan Young. I’ve only heard excellent reviews about Bradford Ignitions so whatever advice they suggest I’d go with.

Hi. If it’s the twin map leonelli stator (two plugs with 3 wires two each and a yellow wire then the hall sensors are the SS543AT unipolar ones with what I believe to be 6.3Mohm pull up resistors.

Thanks Tony - Its for he twin map Leonelli system. Checked readings of pulse triggers as you suggested - one reading dodgy. Would make sense that it would be causing the problem of inability to Rev beyond start up rpm as it needs both triggers to operate the CDI system. I’ll try changing the Hall effect chips and there associated pull up resistors next week once I receive them (ebay). Hopefully a cheap fix. If it solves the issue I’ll put the trigger circuit diagram and parts required on the post.

Thank you for your insights and suggestions. Stripped carb again. Ultrasonic clean - all appears as it should. Float hight ok etc. All electrics in good condition with low impedance earth connections. Timing is correct when strobed when kicking over but as soon as it starts running the timing is all over the place, maybe firing every 3 - 4 revolutions and no response to throttle. Upon closer inspection it looks like someone has had a crack at replacing the Hall effect sensors for the stator trigger. I’m convinced that the problem lies with the ignition. Hoping that someone can say they had the same symptoms and that it was the stator. Thanks Tony - Its for he twin map Leonelli system. Checked readings of pulse triggers as you suggested - one reading dodgy. Would make sense that it would be causing the problem of inability to Rev beyond start up rpm as it needs both triggers to operate the CDI system. I’ll try changing the Hall effect chips and there associated pull up resistors next week once I receive them (ebay). Hopefully a cheap fix. If it solves the issue I’ll put the trigger circuit diagram and parts required on the post.

Thank you for your insights and suggestions. Stripped carb again. Ultrasonic clean - all appears as it should. Float hight ok etc. All electrics in good condition with low impedance earth connections. Timing is correct when strobed when kicking over but as soon as it starts running the timing is all over the place, maybe firing every 3 - 4 revolutions and no response to throttle. Upon closer inspection it looks like someone has had a crack at replacing the Hall effect sensors for the stator trigger. I’m convinced that the problem lies with the ignition. Hoping that someone can say they had the same symptoms and that it was the stator.

Hi. I’ve completed a full rebuild of a 01 250 sherco. Bike was a not running when brought. Tried starting it yesterday and found that it would start but only tick over at idle rpm. Throttle position and mixture screw adjustments made no difference. Spark plug very black. Timing light shows around 5 degrees advanced and the stator plate is in the fully retarded position and firing also seems intermittent. I’m guessing that stator trigger circuit or CDI is the issue - anyone seen this before and can suggest anything to try before sending the stator out for repair? Many thanks.