Hi CBF250 owners. Does anyone technical know what the ignition coil primary & secondary resistances are please for the CBF250 as the only manual doesn’t give us any idea of specs? The barn find CBF250 2008 I bought only shows a primary resistance of 0.5 ohms and secondary resistance of 13,500. The spark test shows a very tiny orange spark, which is a weak ignition system. The reason the bike won’t fire up. In the UK finding a compatable coil for the CBF250 is virtually impossible. Has any CBF250 owner exchanged their coil with success for another type, if so what works? Fitting the wrong coil could ruin the also rare CDI. Any advice is greatly appreciated riders & wrenchers. Many thanks Hog
Is the alternator hv winding generating the high voltage required to charge the CDI unit These windings can go open circuit you should take out the plug ( to make life easier connect an ac voltmeter to the CDI hv input and then kick/ crank it up see if you get the voltage The ignition coil for a CDI unit normally has a very low primary resistance Trev
Hi Trev! Thanks for your reply buddy. The bike cranks with gusto but doesn’t fire up. I can’t test the alternator as it won’t run mate! I bought the little bike for my lassie and she’s really disappointed that someone sold us a defective bike. Best Gog
As ignition coils are a very simple part, it is extremely rare for them to be faulty. On the other hand, you can expect the TCI unit to be your problem.
the engine does not need to run !Do you have a multie meter ? you need to connect to the high voltage coil that goes to the CDI unit then set the meter to ac volts ! Crank the bike up and the meter should indicate a voltage If it does the Cd1 is possibly faulty if not you may have a faulty hv winding I mention this as I had the same thing on my Honda Trev
Thanks for your advice buddy. How do you thorough tests on these cdi’s please? One came with the bike and the other was an Ebay purchase ‘off a running bike!’ it maybe be true. Many thanks Hog
Hi Trev Thanks for your advice buddy. To do a leakdown test the bike needs to run. This is what another member advised. I will certainly try this. I also bought a genuine Honda coil and it didn’t do very much. Another member advised the ignitor circuit on the stator could be the none spark problem. If the ignitor circuit doesn’t boost the spark, then it will never fire up! In the UK a new Honda stator would cost £260 Brit Pounds. Has any CBF250 owner bought a cheaper new pattened one off Ebay? Thank you everyone for brain storming this good cranking, but not firing CBF250. Best Hog
You do not have to have the engine running to do a leak test. Put a fitting in the plug hole, add 30psi from air line and listen at carb, exhaust and gearbox filler hole to hear where air is going.