CBR600f running on 3 cylinders

[andym]

I figured I'd do a few checks before asking the good people here, but now I'm running out of ideas. I've only noticed a problem at higher speeds, but around town there doesn't seem to be any problems.
I only noticed the problem after getting a bit of oil on the exhaust I noticed it burned off on cylinders 2, 3 and 4, but not 1

So far I've done the following:

The carbs have been stripped and cleaned (twice)

Checked for spark on a spare spark plug with the lead from cylinder 1 and then 4 to check it was the same

Removed the spark plug from cylinder 1 and checked the condition of the plug and the spark (plug looks fairly new, a little bit whiter than I'd have hoped, but not major)

Compression test shows cylinder 1 is at ~155psi

Switched the leads from cylinder 1 and 4

Tried a spare HT lead

Checked temperature on all downpipes: 4 ~250°, 3 ~250°, 2 ~240°, 1 ~25° (just slightly above room temperature)

Checked for vacuum on all carb trumpets (no difference between the 4)

Swapped coils around (obviously with HT leads).



The only things I haven't tried (yet) are checking the voltage going in to the coils (although I'd have thought that since I'm getting the same spark on leads 1 and 4 the voltage is going to be the same).

Balancing the carbs... which if the balance is completely out on cylinder 1 and 2.
1) Would it cause a fuel starvation feeling at higher speeds?
2) Where would the manometer be attached to? (I've balanced the carbs on the zxr and gpz which just had little rubber covers on the carbs, but can't find anything similar on these ones)
3) Where is the screw to balance the carbs?
4) Anyone local (Glasgow) that has a manometer I could borrow for an hour or so (I don't have any hoses to make one)
5) What would be the easiest way to get fuel in to the carbs as the fuel line is only a couple of inches long so I can't suspend the tank (also has a vacuum line)


Any help greatly appreciated

[Bikeless]

The layout is similar to the fireblade I think so balancing ports are under the carb inlet rubbers, balance screws are between the carbs.
Have you checked the diaphragm rubber in the top of carb 1 and the slide is free moving?

[mudcow007]

choke on my bandit caused all sorts of weird an wonderful misfires

maybe be worth looking at?

[andym]

Thanks No Blade, I'll have a look on the carb inlet rubbers to see, although I can't remember anything on them.

I found the screw for balancing and counted the turns until there was resistance then turned them back out the same number of turns, 1 & 2 was around the same as 3 & 4

I've checked and rechecked the diaphragm and slide and both are fine.

Also checked power to the coils and with ignition it was 12.3v on each side.

The only thing I've noticed different, which will mean taking them out AGAIN, was when I blew down the carb vent hoses the petrol would spray out one of the holes in the attached image, whereas cylinder 1 it would push up through the main jet

[andym]

So last night I used a full can of carb cleaner, eyeballed the balance, warned the carbs that if they didn't play nice I'd be setting fire to the bike....

After I got everything back together I fired her up and almost instantly pipes 1, 3 & 4 were turning the spray to steam, but cylinder 2 wasn't doing too well.

A quick blast sorted cylinder 2, so after a quick scrub and motorway blast it sounds like this:

https://www.youtube.com/watch?v=tFpe83d-S4U&feature=youtu.be

[Minty]

You have made sure all the plugs are tight? One of mine worked loose recently and caused a misfire.

Rule out the simple before the complicated.
____________________
My fingers smell of your mum.

[andym]

[Minty]

Oh, soz, cant access the yootoobes at work. Glad is sorted.
____________________
My fingers smell of your mum.