Non Starter Fuel issues???

[Rozabikes Tim]

Actually got round to playing bikes this weekend.

Got a 400/4 about a year ago. Would not start - nasty gummed up carbs. Stripped them and part way thorough cleaning them with ultra sonic cleaner etc. (did this when I first got the bike but not touched it since)

Anyway picked up another bike the other week, again a non runner but nice bits to cannibalise. Thought I would try carbs on existing bike. Didn't want to get into full strip of them, just see if the bike ran. So I have serviced them from float bowl end only. Cleaned  everything up and blew through all orifices / jets. Although I have a full service kit I replaced main jets only for now as I just want to see how bike runs before strip down. Cleaned emulsion tubes and set float heights.

Good spark, timing seems fine but will only fire occasionally on the odd pot when trying to start it. Had it running for a couple of seconds with easy start too. PLUGS ARE DRY!

Fuel in float bowls, no leaks all looks fine really.

The only jets I didn't clean were the air screws. On removing the 2 in situ on the outside carbs, these they are covered in a wet reddy brown mess, not clean fuel. No more time today but before I take carbs off again to look at this, would a blockage here stop it starting with symptoms I describe? 

Over to you experts!  Any help appreciated.


Tim

[Bryanj]

Very much so as if blocked no fuel on idle circuit

[Rozabikes Tim]

Thanks Bryan.

Blew air jets though tonight and it fired up on 3 initially. Plug wet on cold cylinder, so looked at spark again but all ok. Eventually blocked intake of that cylinder when running and it must of cleared some other residue, as it then chimed in on all 4 pots. I had to stop at that before I got grief for waking kids but looks promising.

[Rozabikes Tim]

Got the bike running. Starts dead easy and ticks over very nicely. Not ridden it but seems to rev quite cleanly.

When it is  ticking over it smells like its running very rich.  Would this be the air screws which I set at 2 turns for starters per Haynes manual. Not played with these yet but apreciate comments on the possible cause.

Tim