CBR250 Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hey everyone.
My Cbr250RK mc19 is not sparking on cylinder 2 and 3 when the engine is cold. Once the engine starts to warm up, starts running on all 4 cylinders but misfiring on 2 and 3 sometimes. ( I Know this, as I have put the ignition light onto the HT leads.
The ignition on cylinder 1 and 4 is 100%.

I have tested the HT leads, the ignition coil for cylinder 2 and 3, pulse generator, voltage going into the coils and checked for any broken wiring in ignition system.
Readings I got from the pulse generator didn't match the service manual at cold ( below spec ), but once it warms up it goes ( above spec ).
Also the ac voltage coming for once pick up sensor on the pulse generator is 1.3V and the other is 2.0v. ( other pick up sensor is 3.0V all the time )
I haven't tested the C.D.I unit as I don't know a accurate way of testing it.

Does anyone have any ideas on what to test next or is the problem the pulse generator?
 

·
Registered
Joined
·
405 Posts
It sounds like a valve clearance problem to me (valves not closing until cylinder head temp increases due to expansion)
Check your valve clearances.
Tiny
 

·
Registered
Joined
·
541 Posts
Try a different pulse generator, but if it was at fault I'd expect all four plugs to be misfiring. The only thing common between cylinders two and three is the coil, unless you've got two bad spark plugs. Try swapping your coils over and see what happens. Good hunting! :)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Try a different pulse generator, but if it was at fault I'd expect all four plugs to be misfiring. The only thing common between cylinders two and three is the coil, unless you've got two bad spark plugs. Try swapping your coils over and see what happens. Good hunting! :)
Cheers for the reply mate, that was my thought too when i got the reading from the pulse generator. Have tried swapping the coil for one that does work, didn't make a difference, connected timing light to HT leads, so i wouldn't thought a spark plug would affect the light from flashing with the pulse through the HT lead.
Have been thinking it may be the C.D.I unit, but the guys at work don't think so.
Do you know a way of checking a C.D.I unit?
 

·
Registered
Joined
·
541 Posts
I don't know of any way to test the CDI, but from experience they fail VERY rarely. In your case, I'd go back to the pulse generator, if its giving different reading from cold to hot, try find a replacement and see what that does. I see you're in Hamilton, try calling Glenn at Just Fairings, he's Waikato based and a bloody good guy to deal with. I've just checked the parts diagram on CMSNL.com, and it looks like the pulse generator is different on the MC22, so you need to make sure you get one for your MC19. (Otherwise I would've loaned you my spare one!) Good luck!
 

·
Registered
Joined
·
541 Posts
Wait, I just re-read your original post, are you saying there's no spark as in the spark plugs aren't firing or no spark as in the cylinders aren't making combustion? Because that is two totally different problems. No spark, check plugs, work backwards from there. No combustion, could be (as generator said) check valve clearances are correct, check carbs are balanced properly and clean and tuned properly. Let us know. Thanks :)
 

·
Registered
Joined
·
9 Posts
If you need new pickups send me some detailed measurements and I can supply aftermarket ones. No need to replace the stator coil.


Sent from my iPhone using Tapatalk
 
1 - 9 of 9 Posts
Top