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Z1000 No longer starting after carbs replaced.

Posted: Mon May 27, 2013 2:38 pm
Author: JohnC
Hi All. I recently replaced my Z1000's GSXR1100K carbs (it ran great with these why did I bother with bloody 30 year old carbs!! :) with 'more period' VM29 MM smoothbores, bought from the adverts in here. I rebuilt the smoothbores with over £200 of new parts from Allens Performance (on their advice with all parts that might cause problems), float valve assemblies, needle jets, drain screws, main jets, venturi Blocks, gaskets etc etc.

I started the bike up yesterday and it seemed to run OK (if a bit rough as I'd only statically balanced the carbs, but it idled ok and seemed pretty much fit for a first run). No fuel leaks, just a bit of backfiring which tightening up the inlet rubbers etc and a bit of tweaking of the pilot jets etc seemed to cure. Started and stopped it loads of times yesterday and all seemed OK, this was obviously prior to fully balancing the carbs.

After fully charging the battery last night with an Optimate I went out and tried to start the bike again today and it was like a completely different bike, just wouldn't start, chugging and backfiring like hell, and when it did start it only ran on cylinders one and two, three and four stone cold.

Checked spark (Dyna ignition) and all plugs were sparking OK so not a coil or ignition problem (so I thought).

Checked the fuel, checked tank tap and removed drain plugs and fuel was reaching each carb.

One drain plug had dodgy threads and will now no longer seat tightly so this will need to be replaced, but wasn't leaking previously.

It turns over fine, just wont fire worth a damn.

Have I a shim / valve problem?

I did replace some shims a while back and as said the bike was running fine yesterday after numerous start / stop sessions?

I'm at a loss unless something is preventing the fuel reaching number one and two cylinders.

Help!!!

John

Posted: Mon May 27, 2013 3:12 pm
Author: JohnC
Update: Just had another look. I took the tank off earlier but I never noticed this. Both coils are red hot when touched, and this is with the ignition switched off!!!. The coil on the right hand side of the bike is cracked (Dyna) around the middle, so I'm guessing this is NOT GOOD!!! Even though the spark plugs seemed to be firing OK.

Is this some sort of major shorting problem elsewhere? Or just the result of a duff coil. Dyna coils seem to hate me as I've had a couple of failed Dyna coils in the past.....

I also noticed the rectifier / regulator was a bit loose, if this makes any difference. Or, could my regulator have failed and my bike is over charging?

John

Posted: Mon May 27, 2013 3:25 pm
Author: JohnC
Does this make sense to anyone? I did disconnect each plug to check for a spark grounding each one against the engine :(

http://www.kzrider.com/forum/4-electric ... e-question

Or:

http://www.kzrider.com/forum/4-electric ... 0&start=20

Posted: Mon May 27, 2013 3:46 pm
Author: ZedHead
If the coils are cooking even when the ignition is off you definitely have a problem elsewhere. Since the bike was running ok before your replaced the carbs, I would suspect you have accidentally caught the wiring under the tank somewhere introducing a short.

Posted: Mon May 27, 2013 3:49 pm
Author: JohnC
Checked all the wiring, no change since tank was put on m8 and all was well then, so I cant see any probs caused since OK last night and foobar today :/

Posted: Mon May 27, 2013 3:57 pm
Author: z1bman
with the ignition turned of check for any voltage a the low tension side of the coils you should not have any voltage with ignition in the of position.

Posted: Mon May 27, 2013 5:35 pm
Author: PaulMceleney
could be your condensers this happen to me ,on one of my bikes had a spark fuel compression no bang why not faulty condensers

Posted: Mon May 27, 2013 6:57 pm
Author: z1bman
have you done a compression test?

Posted: Tue May 28, 2013 6:36 am
Author: JohnC
I've not carried out a compression test z1bman, seems to have tons of compression going by just kicking it over. Do you suspect something other than the coils being buggered?

Posted: Tue May 28, 2013 6:38 am
Author: JohnC
paulmceleney, I've Dyna ignition so no condensers.

If I had accidentally left the ignition on I'm guessing this would fry the coils wouldn't it.

Posted: Tue May 28, 2013 6:55 am
Author: z1bman
is fuel reaching the cylinders / are the plugs getting wet?

Posted: Tue May 28, 2013 7:00 am
Author: z1bman
yes you should not leave the ignition on for more than a few minutes this is what has caused the coil to overheat + crack + you need to check your charging system

Posted: Tue May 28, 2013 9:11 am
Author: JohnC
Yes the plugs are wet. They were all sparking but obviously not as they should be. When you say check the charging system what do I need to do? I'm hopeless with electrics and only today bought a mulit meter!! :)

Posted: Tue May 28, 2013 9:44 am
Author: z1bman
if the plugs are wet it is obvious the spark is not good enough to ignite the fuel. once you have it running put your meter test leads across the battery terminals + rev the engine to about 4/5 thousand revs you should have about 14 volts at the battery any more than 14.6 volts indicates a faulty regulator / rectifier

Posted: Tue May 28, 2013 11:02 am
Author: JohnC
Cheers m8, I've ordered up up some new coils so hopefully (possibly the wrong term!) all I've done is -palm face moment - left the ignition on and nothing else is amiss. A bloody expensive mistake at £130 for new ones :/

I've checked the coils again today with no ignition on and they are not heating up plus the meter isn't showing anything amiss as far as I can tell.

Oh well :)