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DHLA Tuning
kendo - 15/6/09 at 09:28 AM

A question for the dellorto experts out there. My engine (1600 xflow on twin 40 dhla's) is running way too lean at idle. As a result is spitting back and very hot. The mix screws are wound all the way out but still too lean. The idle jets are .58 so I can only go up one more step to .60's. My question is, is that likely to be enough?

I should add the timing looks good.

cheers

Steve G - 15/6/09 at 09:44 AM

How long is a piece of string.......

You'll only really know using a gas analyser to be honest.

dhutch - 15/6/09 at 10:54 AM

quote:
Originally posted by Steve G
How long is a piece of string.......

You'll only really know using a gas analyser to be honest.

How would that work. Go down to the MOT man and get him to run it thought and give you a print out?

02GF74 - 15/6/09 at 11:22 AM

how is carbed fixed to manifold?


no chance of a carb-manifold air leak?

kendo - 15/6/09 at 11:49 AM

The carbs ar mounted using proper seals and the rubber compression washers all set at the right gaps. I don't think I've got an air leak. That said it is not something I've expressly checked for.

Steve G - 15/6/09 at 12:27 PM

quote:
Originally posted by dhutch
quote:
Originally posted by Steve G
How long is a piece of string.......

You'll only really know using a gas analyser to be honest.

How would that work. Go down to the MOT man and get him to run it thought and give you a print out?


Well that would be better than guessing based on internet forum tuning. A colourtune would get it approximated but the only way to get it spot on is to set it up properly with a gas tester. Rolling road session is always best in my book.

As mentioned though - worth checking for an air leak on the manifold first

PaulBuz - 15/6/09 at 03:34 PM

Hi
1st question, which dhla's?
If they are emmision specials, they are jetted totally different from normal dhla's.
Whats the letter after the DHLA bit?

kendo - 16/6/09 at 08:30 AM

they are dhlA 40h

PaulBuz - 16/6/09 at 04:37 PM

Yep. they are emmission carbs.
This is the place to ask about them.
http://www.sideways-technologies.co.uk/forum/Blah.pl?b-Del1/

MikeRJ - 16/6/09 at 05:11 PM

That's a great forum, thanks for the link!