Interesting Weber jetting

[ENTDOC]

let me know how it all works out as I am about to finish the CAV upgrade with Ians shifter, IDA's and sound deadening.

[Eljaro]

And it's confirmed! I just installed a set of 40mm chokes and the motor feels like a totally new machine. It was a fairly easy swap except now I know to be very careful when pulling the squirters out not to lose the O rings The set I got from Vee Dub Parts were beautifully machined pieces, a far cry from the original 37mm cast ones originally in there. They slipped right in, nice 'n shiny.
I just drove a mile home from the shop; not even far enough to warm up the oil but without touching anything else, the idle is smoother, no spitting, sneezing or coughing coming off idle, and a quick blip of the throttle and she just jumped without any hesitation or transitional hiccups. Yey! I gotta give her a workout tomorrow!

Well, glad to hear that the 40mm Venturis work well on a 302 also.
Dont know how come the word spread that the 37mm were the chokes to use for everyday driving.
Maybe for the layman in anything mechanic it is best to leave the webers as they come, but for anyone wanting to tinker around it is fun and definitely brings driving improvement. Doesn't it ?
I bet once you try larger chokes you get the real Weber feeling.

[dlampe]

I have 2 sets 45mm chokes. I wonder if that is just to much? I think I might give them a try this winter. It really isn't that hard to switch them out. My mill is a 380 with Yates heads that really breath well. Any idea how this could effect my jetting? I am currently running 40's.

[Jac Mac]

Originally Posted by Eljaro

Well, glad to hear that the 40mm Venturis work well on a 302 also.
Dont know how come the word spread that the 37mm were the chokes to use for everyday driving.
Maybe for the layman in anything mechanic it is best to leave the webers as they come, but for anyone wanting to tinker around it is fun and definitely brings driving improvement. Doesn't it ?
I bet once you try larger chokes you get the real Weber feeling.

600cc(292ci) per cyl----38mm for Hi Perf Road---41mm for competition
650cc(318ci)-----------40mm-------------------42mm
700cc(342ci)-----------40mm-------------------43mm
750cc(366ci)-----------42mm-------------------44mm
800cc(390ci)-----------42mm-------------------45mm
850cc(415ci)-----------42mm-------------------45mm

Starter main jet size is approx choke size x 4 ( eg 45mm choke = 180 main)
On IDA Air Corr should be about 40/50 less than jet for comp- perhaps 30/40 less for road. Use Air & Emulsion to tune for each individual engines characteristics- Once you get more than 10 away from that starter size of the main jet you are chasing Fairies!

Jac Mac