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MillarsCB400SF
New Member
United Kingdom
47 Posts |
 Posted - 26/09/2007 : 19:17:00
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My CB400SF (93) has developed a problem. Starts fine, runs fine, get about three miles and then she dies, still have electrics but no spark, it then won't start.
Leave it ten minutes, it starts and runs fine for a further mile or two and then dies again, this continues.
Had a mechanic look at it and they decided it was the CDI. Changed it for one that I know works and it still does it, however this time you can go that little bit further before it does it.
When it dies there is no spark at all.
The leads have been tested and are fine.
I'm lost with this one, can anyone help please.
Ian. |
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Yorkie
Settled In Member
United Kingdom
62 Posts |
Posted - 26/09/2007 : 20:34:12
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| is this on a morning ? if it is it could be carb icing although im not to sure if the S4 suffers from this someone else will have to shed some more light onto this if it is |
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rich_miller86
Senior Member
United Kingdom
1453 Posts |
Posted - 26/09/2007 : 21:01:22
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| have you had a look at the air filter recently? |
Suzuki GSXR750 SRAD - North Wales |
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houdini
Familiar Member
Ireland
236 Posts |
Posted - 27/09/2007 : 09:14:58
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| that happened me before it turns out i pinched the airline off the tank and stopped the air flow into the petrol tank |
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TektroG
Senior Member
United Kingdom
1009 Posts |
Posted - 27/09/2007 : 09:43:05
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| Alternator not charging bty? Check voltage across bty when off and running. Off 12.5V ish, running 13.5 - 14V More than 14.5V? Dead reg/rect. No increase when running? No feed from alternator. |
I've got 4 words for you sonny: ... |
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AlanH
Senior Member
United Kingdom
1040 Posts |
Posted - 27/09/2007 : 13:54:36
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A pickup coil fault can do this, Test the resistance when it has conked out as they tend to fail when the motor is hot and cure themselves when the motor has cooled down again. Test it when it's cold and all will appear normal.
I can't see how carb icing, air filter, fuel problems etc would stop it sparking. |
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Eddie v twin
Regular Member
United Kingdom
878 Posts |
Posted - 27/09/2007 : 18:44:30
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sounds to me like the coils which are breaking down when hot, then reset them selves when they cool, check them out for resistance and output
eddie |
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AlanH
Senior Member
United Kingdom
1040 Posts |
Posted - 28/09/2007 : 01:32:48
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It would be very unlucky for both coils to fail at exactly the same time. From the symptoms it doesn't sound like it's running on two cylinders then cutting out completely after a while longer. It sounds like it dies immediately on all cylinders.
In my experience, an inline 4 with carbs dying on all cylinders at once is usually due to CDI, pickup coil, killswitch, ignition switch, sidestand switch or another wiring problem causing power failure to the ignition or false cut-out. Of all these, the one that most often affected by heat is the pickup as it is mounted in the engine.
So come on Ian - get testing and stop keeping us all in suspense ;) |
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MillarsCB400SF
New Member
United Kingdom
47 Posts |
Posted - 11/10/2007 : 18:31:50
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Hi all,
Thanks for your replies.
I looked at all the above and eventually got an auto electrician in (£15 per hr).
He found the problem and sorted it in three hrs.
It turned out to be the crank sensor connection, after a new bit of wire and some soldering it runs better than it ever has.
I did unfortunately purchase a CDI unit-which is now redundant.
Thanks again for all your help.
Ian
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Swann
New Member
Philippines
3 Posts |
Posted - 09/11/2007 : 15:06:23
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I had similar problem with my PB1 2 years ago and It's symptom was:
-- Fuel starvation at high speed (110 kph or higher)
The bike would slow down till the engine died, then start up again after 5-10 mins.
I traced the problem to the diaphram in the fuel pet*Censored*. It had recently been replaced and the mechanic who installed it, allowed the diaphram to get pinched when the valve was reassembled. It wouldn't allow enough fuel through to fill the float bowls on high speed runs. I took the valve apart, reassembled the valve and it was fine asfter that.
Hope this helps.  |
The more you know, the better it gets. |
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