I have got a pair of 40’s to replace my old worn ones. My plan is to swap over the jets, as it ran ok. But then I wondered if I have the optimum jetting? Sadly no rolling roads near me and I know the PO of my bus spent a fortune on rolling road sessions and couldn’t get it running right, (which was fixed by changing the ropey distributor). Here’s a list of the jetting on both - what are you guys running?
If they're comparable to Dells, i'd say the original jetting was fine. You can obsess about these things. What was "worn out" on the old ones? There's nothing really to wear.
The spindles were worn and believe it or not by the time I’d priced them and new gaskets etc it worked out not much more to replace them with new carbs. Ok, they are Webber copies, but my friend who builds engines has had 20 sets of these in different sizes and they are exact replicas and fully interchangeable.
I've got the same as your old ones but 190 Air and 140 mains. I know my mains seem bigger than everyone else's but it runs well. 2056cc, webcam 86 ( I think), 1800 big valve heads, flat top pistons, no idea on CR.
I keep switching mine between the bus and my buggy. 140s and 150s. Tbh I can't remember which is in which at he moment.
I think the mains are too small and the air corrections too big, try 28 Vents 50 Idles 125 Mains 180 Air Correction F11 Emulsion Or leave it as they come and see what happens. For what it’s worth I have: 32 vents 55 Idles 125 Mains 180 Air Correction F11 Emulsion 2316cc, C25 cam, 9.0:1 CR, 1800 heads with 41mm inlet and 34mm exhaust valves. Incidentally, IDF spindles run in bearings, they don’t wear and I’d put new bearings in the original carbs - if that’s what they need. Some copies are good, some not so good, QA is definitely sketchy or non existant. Completely strip and clean the carbs to remove the construction debris and check the float height.
I don’t know anyone running 145mains in IDF 40’s but your Weber copies might work like that. Try it and report back.
So ignore what I said on mains I'll be getting some 125s and 130s to play with too. 77 Westy and Zed are the one's to listen to.
Thanks, I am amazed by the quality of the repro, I’ve set the floats, and will give them a good clean, but they look spotless. I’ll post some pics up. I will rebuild the webers, there was definitely wear in the spindle bearing, but this way I can do it in my own time while getting the bus back on the road.
What carbs are they? Dells IME seem to like a bigger main, mine like 135 with a 30 choke, I tried smaller but it just doesn't like it, the head temps soared before I even got above 50mph. With a 32 they are ok-ish with a 140 but it gets a bit lean WOT at the top of the rev range. So Dells and a 30 vent, I'd stay at 135 seems perfect, IDFs seem to cope better with a smaller jet.
Italian IDF40s with 28 vents. I'm going to get a few more smaller sizes to play with. I've tried 150s and 140s and it runs fine. Thing is I've know real way of measuring what's good.
I think you'd find you are way to rich if you could measure it. 'appen you could go safely down to 135 or 130 as Mr Westy suggests, particularly with those smaller vents.
I'll get both I think. The buggy has identical carbs so it'll be good to have a full set between the two.
