So the engine has been in for a while now, and I've spent a lot of time (and money!) getting the jetting sorted, and I think I'm nearly there. I had it on a rolling road but that was a complete waste of money, I think they weren't familiar with the engine and/or carbs and weren't prepared to do the research.
I got a zeitronix ZT-2 wideband to help me dial the jettng in myself. This has been a lengthy process, partly because a couple of things caused me to chase my tail for quite a while - the first was the 123Ignition distributor. This was just not working with the motor, and I tried to fix it with the jetting but it really needed a vacuum advance to help on progression. I eventually admitted the 123 was an expensive mistake and got a pertronix, immediately much better.
The second issue I had was the idle jets that came with the carbs. With the stock 50 idles it was way rich, switching to 47 made it undriveably lean, and 49 was a bit better but still lean. After swapping them out several times and trying different things, I finally realised that the 50s must have been reamed to a larger size. I tried 52 and things instantly started looking better. Still slightly rich, but I have (real) 50s to try next. There's a wideband thread on the samba where john from ac.net repeatedly tells people not to assume jets are labelled correctly. He's right.
The mains started at 115 and lean, so I've gradually been increasing them until I'm now on 135 and still a tad lean, 140s next!
This is the place to discuss, or get help with any of your Type 4 questions.
Moderator: Type 4 Unleashed