Reply To: No spark – GT250 Carby
Hey,
I am very happy for you that the bike finally ran, i did think the CDI was sort of the last resort item for sparking woes, now if anyone has similar woes, i will make sure to make them digest this topic. Very informative! Hell, you even laid out you tested some electrical components and what the specs are.
Usually some folk can’t or won’t want to read the manuals if it is too confusing for them , but not always!
I’m quite jealous you won a cheap auction backup bike but that will come in handy as parts donor for your racing days, you won’t have to wait to replace anything or just have an extra girl ready to go! A little switcheroo won’t hurt haha.
As for the harness, if the ignition system has to pulse 10,000v to spark the plugs, i would not be surprised if the koreans added one way diodes or some other mystery sensors embedded in the harness so that things don’t retrograde back if something doesn’t go to plan.
The horn does draw some power to be fair and it’s always live (as long as engine is running) , so all the rider does is press the horn button to complete the circuit. You don’t have to be a full electrician right now to know sometimes bad coils will arc the sparks or zap signals out of their HT leads , the harness must not get fried back or the cdi. It isn’t fool proof since the stator unit can still blow the cdi or blow ignition system system.
Just make sure it produces 70v around 5k revs and never exceeds 90v in any revs , it is almost the hottest thing on the left side of the lower crank.
When starting the bike -> magneto tells cdi how fast the rotor is spinning -> the CDI then tells the dash board (rpm signal bouncing around 600 rpm) , now the cdi next has to communicate with the rest of the ignition system to spark the plugs (as long the clutch switch & kick stand doesn’t prevent the CDI from doing so – – ie. safety cut out — (ie to avoid setting off with the stand down or starting the bike without holding clutch)
Neutral sensor isn’t foolproof , it may say N but gearbox may still be “slightly engaged” , alas when bike starts , it rolls 3 seconds later and falls , oh yes , i’ve witnessed it haha. I always make sure to roll the bike forward and back anyways to make sure its really neutral , keep gear linkages greased up and sparing no expensive on quality oils. That will keep the valve train silky smooth (oh yeah, the engine doesn’t have a camshaft under the gearbox too)
// Meditation doesn't mean you have to sit still....
