Carb tune -up

[Vindicator]

Hi Guys, I mentioned in another post that I'm going to balance the Dellortos with a Carbtune. It's the first time I've touched carbs for years and the last one I touched was a twin SU. I have clear instruction for the Carbtune and it looks pretty straightforwards but I have a couple of questions I'm hoping to clarify.

The instructions make no mention of the air filter and I was wondering whether the carbs should be balanced with the air filter on or off? I don't want to melt the filter if it blows back 

I also have seen no mention of setting the 'mixture' (air fuel ratio). I can't see from the instructions that balancing will affect whether the engine is running rich or lean over all (mine is grossly rich at the moment). Is there another adjustment process I need to go through after balancing the carbs to adjust the 'mixture'? Or is this more the dark art of re-jetting? If it's not part of the balancing, I can't see how you would adjust the 'mixture' on 4 carbs in unison.

Hope I haven't embarassed myself with a couple of naïve questions    I think I know what I'm talking about...honest!

Cheers, Ian

[benchmark51]

I've never used a 'carbtune' , I used a Crypton syncrocheck. To be honest it has always been a 'Fly by the seat of my pants' affair when tuning 40's. Would take all night to explain it all so here's a start that will help.  Click the linky below

http://www.lotuselan.net/forums/lotus-carbs-f40/help-tuning-the-dellortos-40s-t13545.html

[Vindicator]

Cheers Dave, I'll take a look, Ian

[Vindicator]

An update....had a small issue with one of the plugs which appeared to have a weak spark. It turned out to be oil contamination. Cleaned up and then concentrated on the carbs. Gave them a check to ensure floats ok and then tuned them with a CarbTune. Nice piece of kit and easy to use. It shows the vacuum on all cylinders at the same time and sets the mixture as well as the balance. Car now running clean with no petrol from the exhaust. Pulling smoothly. Very happy with the result. Put car in for it's MOT......passed with no advisories

[Facial Hair Optional]

Do you have a link to that CarbTune item pls? I can only seem to find ones for bikes.

[Vindicator]

Hi Steve, this is it.....ignore the first bit about setting up the carbtune...

www.mlmparts.com/media/pdf/carbtune/using-carbtune-ii.pdf

I've seen another similar set of instructions which are not as carbtunecentric. I'll let you have a link when I find it.

Ian

[Facial Hair Optional]

Much obliged!

[Vindicator]

Here's the other one, Steve...

http://espritfactfile.com/carbbalancing.html

Ian

[Facial Hair Optional]

Aha! Brilliant, thank you Ian!