Title: Tuning issues with 42 DCNF's Post by: nlvtinman on October 22, 2015, 01:41:32 am I am finding the tuning expertise of the 'ole dawg I am now, not as sharp as 35 years ago. Working on tuning the 42dcnf's on my new 1776, I have both a slight low end bog at acceleration, as well as a stumble when say making a "U'-turn.
Air correction 180 Emulsion tubes f-25 Main 135 Idle 55 Float set at 48-58.5 mm heights, 10.5 range Heads are ported, 40 X 37.5 valves, port matched manifolds. I can't find any information in the numerous Weber online forums which notes correction to such problem, and I'm seeking advice on what I can do to make things right. Anyone with the knowledge at the Lounge that can give me guidance? I thank you all in advance, Steve Title: Re: Tuning issues with 42 DCNF's Post by: nlvtinman on October 22, 2015, 12:59:29 pm 58 viewers yet not one shared idea?
Title: Re: Tuning issues with 42 DCNF's Post by: dive!dive! on October 22, 2015, 13:28:53 pm Did you check the pump jet squirt is ok and measure the volume delivered ? This can have a huge impact on driveability.
Title: Re: Tuning issues with 42 DCNF's Post by: Pedalpusher on October 22, 2015, 16:57:15 pm When making a U-turn, I suppose it is flooding the carbs a little due to the breathing hole of the fuel chamber locating right next and a little above to the main jet stack?
I soldered small copper tubes as an extension for the breathing holes, like snorkels. So I have never had any cornering issues. ANd you should check what pump jets they have on now, that would give a little information as well. Title: Re: Tuning issues with 42 DCNF's Post by: nicolas on October 23, 2015, 04:26:53 am check for a plugged idle jet. on my DCNFs i never had issues when making U-turns, but the extensions like posted above can make a difference. i don't have them but i have considered them as well.
from memory i had the exact same jetting on my 42's in my 1776. hope it helps. Title: Re: Tuning issues with 42 DCNF's Post by: MC Dyno Don on October 25, 2015, 03:58:32 am I have had similar experiences Steve and would suggest you check the fuel for any water contamination. I recommend you to use some marvel mystery oil in your tank and drive for a day and determine if it solves the problem for you. Good luck !!
Title: Re: Tuning issues with 42 DCNF's Post by: Joel Mohr on October 27, 2015, 00:07:35 am What vents, and what cam? you could have a low vacuum signal...That will do both...
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