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Post by spannerman0785 on Nov 3, 2017 6:38:29 GMT
I have recently bought 2 honda 250 n bikes with a view to restoring them. 1 runs ok but i cant get a spark from the other despite borrowing the ignition coil and cdi unit from the runner. Any ideas guys ?
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Post by stevie on Nov 3, 2017 6:51:36 GMT
Check your ignition kill switch.
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Post by kickstart on Nov 3, 2017 12:54:27 GMT
Could be the stator ....
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Post by spannerman0785 on Nov 4, 2017 7:56:10 GMT
thanks. will check it out today  |
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Post by spannerman0785 on Nov 4, 2017 8:04:02 GMT
Check your ignition kill switch. its obviously set to the run position. do these switches give problems ? |
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Post by na44superdream on Nov 4, 2017 8:20:04 GMT
When the switch is in run, the circuit is open, when not it earths the CDI and the ignition does not function.You can disconnect the lead at the CDI bullet connector, think it is a black with white stripe maybe. That would eliminate the switch function perhaps?? But the switch could be needing cleaned out if it's going to earth when set at run.
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Post by na44superdream on Nov 4, 2017 8:29:18 GMT
Normal place I would start, is the red connector, lower edge aft end of the left side electrical panel, All the connectors in that are should be sparkling condition, with good connectivity.
With the indication of a neon spark plug cap, my son diagnosed my no spark situation by disconnecting & reconnecting one of the little multi-connectors. Check your main earth on the right side upper engine mount is nice and shiny, with low resistance..(simple things first).
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Post by spannerman0785 on Nov 5, 2017 8:03:40 GMT
ok thanks for that. will be next weekend before i get back on it now. it had a faint spark when i collected it but none at all now
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ian
Member Of The Year 2019 
Isle of Man
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Post by ian on Nov 5, 2017 21:23:07 GMT
Yes, the cdi wire John refers to is black with white strip. It's the single wire going to the cdi, the others going to a multi connector. I'd always disconnect this when troubleshooting no spark, just to rule it out.
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Post by churchman on Jan 15, 2018 9:16:10 GMT
CB250N NO SPARK
SUGGESTED METHOD FOR CHECKING THE SPARK
Connect a Spare Plug to one of the Plug Caps.
Connect this Plug to the Chassis using an Earth Lead.
(This is important)
Make sure the Battery is Fully Charged.
Carry out this Test in a Garage or at Dusk.
Turn Off the Garage lights.
Press the Starter Button.
Is there a Weak Spark or No Spark at the Plug?
A Weak Spark indicates Alternator Failure.
'No Spark' means the Following need to be checked:-
Rectifier Unit
CDI Unit
Isolator Switch (on RHS Switchgear)
(Plug in a Spare to Check these)
Regards
Wilf
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boo
New Member
Posts: 5
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Post by boo on Mar 25, 2018 0:06:19 GMT
ok thanks for that. will be next weekend before i get back on it now. it had a faint spark when i collected it but none at all now HI, OLD BIKES ARE LIKE OLD CARS, 12V TO COIL VIA POINTS AND A CONDENSER, WHEN THE POINTS OPEN AND THE CONDENSER DISCHARGES THROUGH THE COIL IT EXCITES THE HT SIDE OF THE COIL AND YOU GET A SPARK OF APPROX 11000V. SO CHECK AND CLEAN YOUR CONNECTIONS ON YOUR COIL AND CHECK YOUR PLUGS ARE OK IN FACT FIT NEW ONES FOR WHAT THEY COST, I HAD THE SAME PROBLEM WITH MINE WHEN I FIRST GOT IT, I ALSO WAS TOLD THAT THE TWIN COIL CAN BE SUSPECT ON THESE I PICKED A SPARE UP ANYWAY SO I HAVE ONE READY. AS I SAID CHECK AND CLEAN YOUR CONNECTIONS TO THE COIL AND YOUR SUPPRESSION CAPS AND INVEST IN A PAIR OF PLUGS AND GO FROM THERE. YOU SHOULD HAVE 12V TO ONE SIDE OF YOUR COIL WHEN YOUR IGNITION IS ON IF YOU HAVENT CHECH BACK FROM YOUR COIL TO YOUR IGNITION SWITCH, GOOD LUCK DAVID AUTO SPARX  |
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Post by roger64racing on Apr 21, 2018 11:37:18 GMT
The Superdreams have CDI (Capacitor Discharge Ignition), they do not rely on 12 Volts from the battery, in fact you can bump start it (or use the kick starter if it has one) and it will run even without a battery fitted, you do not have a constant 12 volts at one side of the coil. In all my 40 years of being around these bikes I have never known of the CDI box (Under the fuel tank) to fail on the 250s, 400s do sometimes, HT coils never fail on either 250s or 400s. 95% of the time when you have no spark it's the stator that has failed, usually the low speed source coil. I rewind motorcycle stators for a living, I'll be posting a video up on You tube soon on how you can test stators for these bikes. The 400T/N models use Hitachi electronics and the 250t/n and 400 automatic models use Denso electronics. As mentioned in a previous members posting, always disconnect the single Black/White wire at the CDI box, this will isolate kill and ignition switch.
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rod
Junior Member
Posts: 20
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Post by rod on Aug 19, 2021 18:53:07 GMT
Thanks I'm learning i will get my cb 250 running
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