Cylinder Problem

Little Loris · Post by **Little Loris** » Sun May 13, 2007 8:09 pm

I fired up my track day bike today only to find it firing on 2 cylinders, which is odd as it was running fine a couple of weeks ago. Charged battery and changed 2 middle plugs for new ones (2 & 3) and it misfired into running 3 cylinders. Swapped plugs 3 & 4 and it ran on 2 cylinders again. Swapped them back and changed 1 & 2 only to find it running on 2 cylinders again.

Plugs don't seem damp or covered in oil and I've had a spark from all of them. Anyone know what the problem might be? Coils aren't damp either and all connected properly. It's running a total loss system if makes a difference to any problem solving! Please help!

Little Loris · Post by **Little Loris** » Tue May 15, 2007 8:39 am

Bump - Still suffering! Help!

Post by **masterofinsanity** » Tue May 15, 2007 9:07 am

have you checked the earth straps are in good nick, what about the wiring to the coils?

Post by **Northern ANdy** » Tue May 15, 2007 10:13 am

if the original HT leads are still on then its possibly them.

Little Loris · Post by **Little Loris** » Tue May 15, 2007 12:25 pm

How do I know if the HT leads are knackered? I've got a spark in all 4 plugs but maybe not enough spark? Do I test them with a multi meter?

Post by **Northern ANdy** » Tue May 15, 2007 1:34 pm

oh well if they are all sparking they are ok probably, I was meaning that the lead ends could be badly connected as many originals seem to be after repeated services and etc.

Have you tried all new plugs?

Post by **masterofinsanity** » Tue May 15, 2007 3:07 pm

make yourself a new HT lead up and swap them one by one checking for a GOOD bright spark.

ratbag56 · Post by **ratbag56** » Tue May 15, 2007 10:09 pm

u can check the resistance of each lead it tells u how to do it in the manual! if they are not correct then the bike will miss fire

Little Loris · Post by **Little Loris** » Wed May 16, 2007 9:27 am

Swapped the coils over after it failed to fire on 1 & 4 and it ran on all 4 cylinders

Great news but bloody confusing! Swapped them back to original position and fired again on all 4 with a pop from the exhaust every now and then. Very odd but guess it was a dodgy connection somewhere.

Funny thing is, the tacho had been wired up prior to start of all this and it wasn't working but when I switched the coils over it was going backwards?! After I swapped them back to normal it was working at all. What wires could be wrong?

ratbag56 · Post by **ratbag56** » Wed May 16, 2007 7:19 pm

the wires are colour coded!

Little Loris · Post by **Little Loris** » Fri May 18, 2007 11:00 am

ratbag56 wrote:the wires are colour coded!

Er... Thanks for that!

But what could be wrong?

Little Loris · Post by **Little Loris** » Mon Jun 04, 2007 12:39 pm

Went on a track day to test the ZXR400. Got it firing on all 4 cylinders after the routine swap of the coils and HT leads. As soon as I pulled away and put it into 2nd and the revs picked up it went back onto 2 cylinders.

Pulled into the pits and it fired back into all 4

. Went back out again and back onto 2 cylinders. What the hell is going on?!

Is there any way of testing the coils or HT leads? How do I do it? Is something wrong with the CDi unit? Please help!!

Post by **rene** » Mon Jun 04, 2007 1:22 pm

if you hold it at a constant rev's (say 9,000) dos it go back to 2 then?

if it dosnt do the above you must have a lose conection what only happens as the vibrations pick up!

Little Loris · Post by **Little Loris** » Mon Jun 04, 2007 2:34 pm

It was kicking in and out of 2 & 4 cylinders down the backstraight and all corners, so vibrations would be plausable.

What wires should I check for loose connections?