zx-7r running rough sputtery and underpowered

[Gman]

this morning when i went to ride my 1996 ZX-7R was very sputtery, underpowered, running rough and had low idle. i just had it serviced 2 months ago. it was also fine last night when i turned it off. Any suggestions? can it be a plug fouling even if i just had a service?.....and yes the fuel was turned on

[binther]

could be a clog in eather your air of fuel mix.. if a bike is starved of fuel or air it will have flat spots where to jumps and jitters. also all round power will be alot lower.

[Rossi]

More info please.........
Bike garaged or left out in the rain ??

[Gman]

the bike is always garaged. i had it running last night and felt all the header pipes. one is cold which tells me the cylinder is not firing

[Nanna10r]

could be a clog in eather your air of fuel mix.. if a bike is starved of fuel or air it will have flat spots where to jumps and jitters. also all round power will be alot lower.

I'm so proud

I'm tinkin' Helectrics. But Yound Padawon could be right with a carbie playing up.
Either way sounds like your on to it.

[Rossi]

Swap your plugs first - if you ain't got a spare set, shuffle the ones you have fitted and see if the cold zorst follows the dodgy plug
Could also be a coil breaking down but hopefully just a bad spark plug

[Rusty]

Could also be a coil breaking down but hopefully just a bad spark plug

Or a dodgy lead.

[Nanna10r]

These only have 2 coils don't they, so wouldn't that make 2 pots play up ?. If so I'm leaning plug then lead.
Any news "Geeeeman" ?.

[Tack]

There are two coils on the 96 ZX7R. I have run extra wires from the base of the coils to the frame because they are rubber mounted and sometimes don't earth very well through the mounting bolts. Don't a bad mod to do regardless of actual cause.

[mike-s]

ram air and all hosing correctly secured & not got any breaks?

[Gman]

i flogged it and ran high revs and it eventualy corrected. ran good on the way to work monday and then stopped working when i started it to make my way home. Ran on only one 3 cylinders the whole way hom no matter how much i reveds it.

[Rusty]

1. Spark plugs in good nick?
2. Plug leads/boots in good nick?
3. Carbs nice and clean?

I'd be checking the spark on the dead cylinder first. If the plug's clean and dry, clean the carburetor out. If it's wet with fuel, replace plug. If it's still not firing, check the lead.

After that, you get into more expensive territory (assuming ALL earths are good).

[IsleofNinja]

i flogged it and ran high revs and it eventualy corrected. ran good on the way to work monday and then stopped working when i started it to make my way home. Ran on only one 3 cylinders the whole way hom no matter how much i reveds it.

Sounds like a kactus plug there 'Gman'

Iridium plugs seem to have a really bad habit of doing this at very low milage FYI .

Also.
Prob a good idea to check the plug drain holes are clear also (allow oil / water that accumulates in plug wells to drain)
If you pull the lead off on the cyl with the cold header and find the lead end is covered in oil / moisture is a fair indication.A damaged / missing / oil affected rubber boot on the bottom of the lead socket don't help here either.

Which one in cold?

[Gman]

thanks all for the help....i replaced the plugs and now everything is fine