1st Stage Jetting complete on the 906

[higgy]

So I got my idle jets where they need to be. Ordered 70,75 and 80 but after tinkering with it while waiting for the jets,I decided to go straight for the 80's.
Idles nice and even now,idle screw is at 3/4 and air bleeds are at 1.5 nice and steady at 950rpm. Absolutely no sign of the hesistation now in the transition from idle. Nice blue flame.( colortuned)
I still am getting an occasional spit from the vertical cylinder but I believe I have a slightly tight intake valve which I will deal with tomorrow along with the mains and ac's.. So here is where I am currently.
44 Dcnf
37 mm main venturi
4.0 auxiliary venturi( was 3.5)
Main 160
AC 175
ET F44( was F27)
Idle 80 ( was 65)
Pump 40
K&N filter
Open air box
Rennsport exhaust
I might try out the F1's but I don't think they will have the same sound appeal as the
Rennsports
Almost forgot, I did replace the standard coils with dc3-1's from dynatek http://www.dynaonline.com/skins/product ... yna_Coils/
I expect I won't have to do much with the main,it always ran strong on the top end,but we shall see,the Ac's will most likely be another story with the new Et's. I have 3 sizes smaller on hand if needed.
by the way, I recorded the initial startup and as soon as I figure out how to convert it to an mp3 I will post a link here
Link to video http://s520.photobucket.com/albums/w326 ... tartup.flv

[JWilliam]

I'm on the edge of my seat Higgy!

[Tamburinifan]

Slight threadjack, just courious, have not searched:
Anyone has Mikuni CV 38mm on a 906?
Better-worse?

[Finnpaso]

Not just to topic, but one of my Pasofriends here(906 and 907IE) have had very good expenrience with just normal 906 Weber and he have been satisfied to it. I have heard many times, that Weber fits much better to 906 than to 750 Paso. He have also quite good consumption ratio with Weber, something very close 5L/100km.

[higgy]

I totally agree,The 44 dcnf works very well on the 906, but there still mainly due to fuel issues these days is room for improvement, after all the carb jetting is 19 years old and fuel has changed radically since then and I intend to go there , does not mean anyone needs to follow
I am also beginning to suspect there is more here than airbox exhaust and coil modifications,While it would not be the first time I have run across such a large change in jetting from such changes I am beginning to suspect the cams have been changed as well. Guess I'll have to break out the old degree wheel and dial gauge blow off the dust and investigate.

[higgy]

Took it out for a trial yesterday. Seems the 80 idles are a bit too much in the warmer weather,mid 60's(15c),
While it runs great from idle through the entire range on acceleration,Response is amazing, steady throttle gives it a lot of surge
and the idle tends to load up and conk out after a few minutes. It reminds me a lot of a formula bike I had many years back,Raring to go and bucking at the bit when you hold it back. So today i'll drop the idles down a bit
along with the Ac's and try it again,more later...............
Yesterdays status,

44 Dcnf
37 mm main venturi
4.0 auxiliary venturi( was 3.5)
Main 160
AC 165(was175)
ET F44( was F27)
Idle 80 ( was 65)
Pump 40

[higgy]

BOOYAH! have the tall 4.5 auxilliary venturi's in my hand. Came from an old ferrari with 40dcnf's and I must say they are gorgeous. Can't wait to try them out.

[Tamburinifan]

Weber porn!

[higgy]

lets hope it's weber on viagra,might as well get something otta all those damn commercials

[ducapaso]

BOOYAH! have the tall 4.5 auxilliary venturi's in my hand. Came from an old ferrari with 40dcnf's and I must say they are gorgeous. Can't wait to try them out.

Is that what they mean with "improve your inner lenght" in my bulk mail?

[higgy]

Took it out today with the 4.5 decided improvement, Think the next step will be to go back to the stock et's. What I would really like to try is an f7 or f8 et but seems to do that I will have to make my own. I think Mr goose was onto the right setup regardless of your displacement when it come to weber carb.

The arsenal to date

[higgy]

Put the stock ET's and Ac's back in.Left the idles at 75.The answer seems to be the tall 4.5 auxiliary venturi's. Acceleration is now even,smooth and easy to regulate. Still there is a hint of surging under 3000rpm on deceleration which I might address down the line with a different emulsion tube/float level adjustment or maybe just one more step down to 70 idle jet,but overall I am happy with the results.
Here is where I ended up.
44 Dcnf Weber
36 mm main venturi
4.5 tall auxiliary venturi( tried 3.5 tall and 4.0 normal)
Main 160
AC 175
ET F27( tried f44)
Idle 75 ( was 65)
Pump 40
K&N filter
Open air box(modified cover)
Rennsport exhaust
3 Ohm Dyna coils and wires
If any one wants to try this,to get the 4.5 tall auxiliary venturi you must look for Ferrari part number 31966.008 which came fitted to a 40DCNF Weber. I found my set at Fast Road Cars out of the UK for 14L plus postaage, about $50 to the US total for 2 venturi's. Anthony also has some good prices on other jets as well and has an ebay store.
Seems to Me I read on another thread here that someone was going to try soldering up the top holes on their ET"S. I think they are quite correct that this would fix the last little bit of surge on decceleration. All in all I think this is a much cheaper route to go than swapping out the weber for anything else. Certainly for a fraction of the price of a set of FCR's

[higgy]

Ordered an Innovative LM-1 today to further my efforts at getting the weber spot on. Had an lc-1 at work and a dyno but decided in the end the lm-1 will suit the purpose better especially with an rpm input adapter............stay tuned when I get the et dialed in I will make them available to all who desire them for as cheap as possible.

[higgy]

For all looking for theory of operation check out this link,Its not written specifically for the DCNF but the principles are the same
http://www.webercarburatori.com/?p=handbook

Has all the same info in any current publication you can buy for free

[higgy]

Lm-1 is installed.RPM lead goes in today. Will be working on a TPS for throttle position trace to correlate afr,rpm and tp. Should all be ready to go very shortly.
For anyone interested
Homework assignment is here
http://www.webercarburatori.com/?p=handbook

The experiment begins soon

Want to know what an LM-1 is all about?
http://www.innovatemotorsports.com/