I have just done the following on my 1993 CBR 600 F2:
Oil and filter change
Air filter change
New plugs
New downpipes
Since Ive done all this, the bike did start up (running really rough though) then died after a little while. Now it won't start and pops a lot (backfires) when trying to start it (this comes from both the header pipe area and the end can). What do you think is causing this? I assumed it was something to do with the plugs not sparking so I took them out and refitted them with no joy. They were quite wet so I'm guessing they might not be sparking properly? They are Denso plugs I bought as part of a 'service kit' from eBay and have checked the codes with the old ones and do appera to be the correct ones. - I assume the plug spacing was correct (they look the same as the old plugs - but I have not idea how much difference minute differences make).
Should I buy a guage for the plugs? Do you think it's something else causing it? - It was running ok before I did all this work :? Oh and I just tightened the plugs up as tight as I could with my fingers and then gave them 1/4 turn with a spanner and then pushed the HT leads back on as best I could, although they almost don't seem secure - quite easy(ish) to pull off.

This is the first time I've done any of this so please don't assume anything, I have simply been working from my Haynes manual - I might be missing the most basic things here lol..
Any help would be absolutly great

 

Did you put the plug wires back on in the correct firing order?

 

There's only 1 plug the one side so thats right. As for the other 3, the deepest plug has a lead right near it (a short one so it 'must' be for that plug)...

Ther other two look right, and the leads are each a different length, the the longer going to the further plug, but I can try swapping these around?

 

You need to look in your manual and make sure, for instance, "plug 3 wire is going to plug 3", etc.

 

Also, make sure your battery is fully charged.

And, make sure the headers are fitting right.

 

Try starting it again and if it still runs rough pull the plugs and see if they are wet.