I've had the dellortos on the ute for about a month now. I've been trying to get them run right for while now. The problem is the engine(I think the carbs)seems to have a bog/flatspot at about 5500rpm to 6200rpm (valves).The carbs have 190 air correctors and 118 mains. the motors standard apart from flat top pistons. I've changed the plugs,coil. Is there anything else to do before I pull the carbs apart and clean them out?

Thanks
Cameron

Cameron, I have had similar problems with my Dellorto's, mine are 40mm DHLA's off of an Alfa Romeo and I got them off the internet for a really good price. On mine I have an Air/Fuel ratio guage to help me tune, and it seems whenever I rev it up, it pulls awesome then just dies off at the higher rpms (6000 rpm to redline). At the same time the Air/fuel ratio guage goes big time lean. I have tried to get rid of it by changing to an electric fuel pump and regulator and adjusting fuel pressure did nothing. I rebuilt the carbs and cleaned them out really good, with no luck...so I think it's just a matter of getting the right jets (slightly richer) which are hard to get for Dellorto's (at least it is in the US). I also think I could go with larger chokes on mine as well, but that won't help the already lean situation. At one point I had the car running super rich and that high rpm problem went away, however it ran like crap everywhere else. If I were staying with the A series I'd investigate it more, or go to EFI, but SR20 is the only thing on my mind anymore. Good luck!

-Andy

Hey Cameron,
Just a few quickies before you drive yourself nuts with the Dellorto Dilemma. Without telling you to suck eggs, make sure that the ignition system isn't breaking down at the higher revs- you may have a voltage drop that indicates the motor leaning out (not enough fuel), but it is in fact, not burning the mix thoroughly. Do all the normal checks for coil, spark plug(s) and leads and ensure that there is no drop through them as well. Check for air leaks around the inlet side of things too...
Through experience I can say that providing more and more fuel to a problem that doesn't require it, ends in tears...

If you are still running the 32 chokes from the alfa you should be looking at the following settings for the carbs

32 chokes, 7772.6 emulsion tubes with 130 mains an 180 airs. 40 pump jets with 45 7850.2 idles.
This is a good start point for 1560 engines using the Alfa carbs.

Well I've fixed the problem, turned out to be the dizzy.It was an electronic one from a pulsar, what would of caused the dizzy to fail like this?

fail like what, what stuffed up on it

I don