Rear Cylinder Not Firing

So a head gasket went on my 99' sv. Up till that point it had run like clockwork. I replaced the head gaskets over a weekend and it fired up straight away, sounded and ran just fine... for a while. About 20 miles later with no warning the rear cylinder stopped firing. I nursed it home and quickly ran out of ideas.

Its worth pointing out that the front is running fine, starts up straight away and happily sits at idle.

Here's what I've tried...

-compression test showed 190ish on the front and rear cylinder.
-check it was sparking on both cylinders.
-swapped spark plugs and ignition coils.
-cleaned carbs.
-checked timing.

I'm out of ideas, any advice would be greatly appreciated. Have I missed out something obvious?

[yorkie_chris]

Is the plug getting fuelly? If you squirt a drop of fuel down the carb does it fire?

the spark plug was covered in petrol when i took it out after trying to run it and dropping fuel down the carb did make the rear fire up briefly, I never would have thought of that, thanks for the tip. So what does that mean? Its not getting enough fuel?

[yorkie_chris]

If it fires with fuel down the carb it means it's not getting enough.
If it's wet it could be getting loads too much (flooding).


How did you swap coils? Leads are different lengths?? HT leads can rot inside, worth changing for silicon ones.

[fizzwheel]

Moved to SV Talk

So I took the jets out and checked they weren't blocked (just for the rear carb) checked everything that could be blocked. Checked the diaphragm, the choke, it all seemed fine. Put the carbs back on and now the fronts not firing either. Gave it a bit of throttle and it just backfired. its stumbling a bit like it might start, but nothing.

Any ideas...