Twin 40's help urgently required

[paulrobo]

I am experiencing a few problems with my Twin 40's. I am running a GTE engine on webber 40's, blydenstien b= (big valve) head and a mild road cam (shrick 280 degree)

The carbs are set up at the moment in the following way.

CHOKE = 30MM
MAIN JET = 115
AIR TUBES = F34
AIR JETS = 160
IDLE = 50F18

Now i have no idea where to start with the jets.... from my understanding the Sport is set up in the following way.

CHOKE = 28
MAIN JET = 100 TO 125
AIR TUBES = F47 OR F16
AIR JETS = 160 OR 170
IDLE = 59F21

The part number of my carbs is 40DCOE 90 and the other is 91, i dont know if that is relevant to anything.

Where do i start with the jets shoiuld they be based around the spec of the sport, and i take it that the OR's are for when the zorst and cam are fitted???

My choke bleeds are 45 F9's and i apparenty have a leak of fuel around these, would a webber service kit provide everything i need to sort this?

Its really starting to bug me now.

With the set up i have at the moment it runs o.k ish but when warm the emmisions are way to high and we cant seem to get them down.

Please help!!! lol :-/

[paulrobo]

lmao... Noce one Micky! lol lol

[james austin]

.......or take it to a RR?!

[paulrobo]

Been there done that.... Dont feckin ask!! lol

[CP]

OK Paul. Your spec sounds sort of in between wot Marks and mine were. I will cross check with him and post direct. From memory the mains want to be 120 + and I think my idles were 45F8's which got the emissions down enough to get thru' a friendly MOT. 30 mm Chokes are fine, we were considering putting 32's but that wouldn't have helped emissions. I think the others sound about right but you will always have probs with emissions I'm afraid.

[MC]

Sounds like your way off actually. The 30mm chokes will be good, you'll get very good torque, if you go up to 32mm you'll loose a little low down torque, but increase peak power. Your choice.

Mains need to be 120 at least. Higher number = more fuel.

I doubt you will be able to get an f47 emulsion tube anymore, thats what I had, and they are well suited to thrashing, not 5mph traffic jams. Try an f8 of f11, this isn't critical.

For the Air jets, you need to be looking at 180-190, the lower the number, the richer you'll be at full throttle. The jets you have are far too small.

I'd recomend trying an F45 for idle, its what I had and it worked.

[paulrobo]

Chhers for the help. It is booked in at Velos for tuesday afternoon. Hopefully that should sort it al!

Seen CP's car up there and Chris Tunnicliffe's (Sp)

Both looking very nice indeed.