Hi Drydreamer,
many thanks for your detailed reply. If you don’t mind my long reply, I re-attach your post and answer one-by-one:
400 system is different to 250.
So I have discovered! I was looking on Dubstep for replacement statues and pickups, but no luck for CB/CM400 twin….and 250 looks simpler….
You have a dmm, good, but get a pair of the red neon plug caps that flash when HT passes thru, but you will have to make an adapter so they will fit/connect. A chore well worth doing as the flashes can be seen ( more easily at night or in shade ) whilst riding the bike.
No flash, no HT, misfire.
I will buy and fit - tho current setup no spark, even weak one …even in total darkness - so it looks like no HT.
A strobe is also good to check ign advance.
Will buy….
A scope would be brilliant but dmm will suffice.
I have numerous analog and digital Tectronix scopes - what would you advise hooking up to, with ground on Green, presumably….?
New HT coil with non detachable leads, but research the GM car coil modification.
No ac voltage at coil.
You are aware that the cam cover is insulated ?
I earth against bottom of block ( shows 0ohm continuity to green wire on stator plug….so a good ground….at least at the green wire.
Using two old serviceable plugs welded ( drill holes and tap if you wish ) to a suitable metal strip, which has a flying earth lead and crochet clip to earth is also a good bit of kit t for these and other applications. Much safer for the fragile ign system and less hassle/more reliable HT test.
New CDI unit, the proper one ?Not new eBay second hand, so could be faulty……but my stator wire resistance checks are all done with plugs disconnected, so ‘open’ connection to CDI, so shouldn’t matter for the suggested maintenance book resistance- checks.
I would have to look up stator resistances, but the stator green wire is a dedicated earth to the stator.
Yes….but it measures 0ohms to chassis, so must be also a common to bike ground.
I assume the starter motor whizzes the engine over well ?
Starter fires well, alternator spins freely, all clean and no inhibitions between brass sender and the pulset pickup ( gap consistent).
As you know, the battery is completely independent of the ign system
Your bike has a kick start also ?
Yes - but new battery and starter/ alternator spin as they should….
Resistance check cold and hot, record the values.
Other than heating outside of alternator with a heat-gun, engine never fires, so won’t get warm. Resistance measured at 17deg C ambient.
Dmm AC volts output check, increase in revs, increase in ac volts.
Max ‘revs’ is the speed of the start motor, I’m afraid - engine doesn’t fire.
But your will not start.
Nope!
Disconnect the cdi black/white wire and try again with good clean plugs and fuel. Black/white wire earthed Via ign switch and handle bar kill switch to kill ignition.
Black/white cable disconnected…..
I’ve tried connecting all connectors, but leaving blue and white wires to chi disconnected and measured ax voltage across the blue-white connectors.
nothing.
Remove oil filter bolt and take it to a nut/bolt supplier, flywheel extracter bolt same thread, the size and pitch of which I cannot remember, 20 X 1.25 ????
Yes - if you’re asking me to remove flywheel cover - I’ll do that.
You need the extracter bolt to get to the stator...
Ok.
Old insulation, flywheel area water drain that doesn't and stater windings covered in epoxy that cracks due to age and heat, taking out windings, make and break and brake and make connections.
Will do, though all the stator winding resistances check out …..apart from white to green ( no 400 ohms).
The dedicated green earth may also be a bad connection.
Green earth buzzes freely at 0ohms to angina block, chassis and to the dedicated ‘free’ terminal below rectifier.
Try cdi kill wire disconnect first and get a flywheel extractor bolt, you are going to need one.
I will extract the flywheel asap ( Saturday) I guess.
I would still love to hear if you know how the white wire connects at 400ohm to Green!
Over....
… but not ‘OUT’ , please - you seem a really great font of knowledge - much appreciated!!!!
cheers,
Manny
