Carb Selection

Don't go to 48 and if it run well, leave it. You can jet up the 40's and they should complement the motor just fine.

Same advice. You've got a well-matched setup right now.

Some 40 IDF's will only accept 32mm venturis while others (that were on European cars originally) will take 34's, so it really depends on what you have. If you bought them new from one of the VW high perf retailers, they're usually the ones that can only take the 32's while the ones guys buy off Ebay from some (I think) Italian dude are take offs from cars and will accept the bigger vents.

So, depending on the porting work, your 40mm Webers may be feeding the engine adequately now, so going to bigger carbs won't do anything except for maybe the last 500 or so rpm, so it really wouldn't be worth doing. Does it rev to 55-5700 rpm with power? If so, it's probably a pretty good combo. If you put 1.25 rockers on it and flycut the heads to up the compression 3/4 point, however, you may find it could benefit from the 44's (or not, you'd really have to try it). If you did take the heads off it would be a good time to have someone knowledgeable look at them and see if they could use a bit more port volume. What size tubing is the exhaust? Oh boy, we're starting to get a little sinceit'sapartitis. Sorry, I'm bad that way...Al

Are you building this engine or is it already together and running? I was under the impression it was the latter. And yes, jets from the 40 IDF's will fit the 44's (and 48's) but you may find that the jetting that works with the 40's doesn't exactly transfer over to the 44's, as the bigger carburetors will draw differently.

Engine is built, just looking at upgrading the carbs.

CRM posted:

Engine is built, just looking at upgrading the carbs.

So, what I said earlier still stands- if the thing already runs to 55-5700rpm with power (3rd gear) then adding 44's probably won't do much. Adding 1.25 rockers, upping the compression a little, and maybe some more porting work will, though. It'll now run to 62 or 6300rpm and it's possible you may need more carburetion at this point. What exhaust do you have on it?

Sidewinder A-1

Tubing size?

I'm running a pair of 40mm Dells on my 2,110 and I think Stan from Stanistan has the same setup.  40's are perfect on a 2,110.  

Thanks Gordon, think I am going to stay with the 40"s.