Hi Steven,

there's not too many (read that as I know of only maybe one guy), who uses a single carb manifold and overall the tendency on this forum is more towards going for two smootbore carbs in order to gain some extra performance.

That said, can you swap the coils between front and back to see, whether the problem goes the same way (it would be the first thing, I would try to have a look at, as it is the only thing left that is individual to one cylinder.
What do your plugs look like, if they are very dark it could simply be, that you're killing them with a too rich mixture ?
Which manifold are you using ? I saw some pictures of manifolds, which were quite appaling realy, when it came to craftsmanship. If so, there's shouldn't be any gaps, weld beads or the like on the inside of the manifold.
Lastly did you overhaul your carb before install and no matter what, unscrew the choke plunger and clean out the seat ?
Do you run a fuel filter and which kind of petcock - if your engine stops of fuel starvation, it wouldn't surprise me.

As you see quite a lot to try out and find out. My best bet is on the electrical side, because that is becoming more and more of an issue nowadays.

Cheers,
Greg

ok I swopped the coils and found that a wire was actually touching the body. fixed and ran it again.
I forgot to mention that I have to bump-start it every time for now.
When it takes it runs perfect for a while and its as if when I let off throttle it starts to backfire and eventually dies.
what should I check for first.
I haven't overhauled my carb so I guess it could be too lean at this stage.

Quote from nanno on 16.12.13 at 10:12:27:

How do you mount them????

Quote from Manfred on 23.12.13 at 13:52:08:

Please expand on the amount of type I am permitted ???

Sorry.... How do you mount different carbs... Do you have them independant  and  use a cable  1 int 2 ????