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> Need help/suggestions/opinions, Carbs
drdriddle
post Sep 14 2024, 09:54 PM
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72 914 with 1.7 that I have been restoring for about a year. Bought it with dual Webers and ran very poorly and made it home 30 miles but with Popping and backfiring the whole time. I recently rebuilt the carbs and installed the jet doctor modification to try to solve any debris clogging issue on the air intakes. Verified dwell at 52, timed to 30 at 3300k. No vacuum advance. Pulling 5’s on the snail airflow meter to all carbs. Made sure to disconnect linkage prior to working on idle. Idle adjustment screw all the way in, then advance to touching the plate plus a half turn. Started with air/fuel needles 1 1/2 out on all four and fired well. Minimal monkying to get the carbs relatively synched. Lowest idle I can consistently get without backfiring is around 930rpm, any lower and I get the occasional pop up through an carb throat and it seems to hunt up and down badly. And I brought it up to temp before doing any changes. Any changes I did, I waited a moment for things to settle before changing anything else.

It runs without popping but big hesitation when advancing throttle for just a moment then she goes well. Runs better off idle circuit, but I’ve read at steady pace some idle circuit is still there? Hesitation from steady pace at slow and mid range rpm…but runs well over 4K without any hesitation when getting on throttle hard. Additionally throttle let off gets me a lot of popping out the tailpipe. I did swap the exhaust for a bursch (sp?) and it sounds awesome btw. No more tinny sounding VW motor

So these are 44’s and everything I’ve read is saying these are too big for the motor size. Strongly considering dropping to 40’s but it’s a chunk of money to do that. I do know that the mains and other jets are the standard sizes, I think 11’s for the mains?(been a couple months since I looked at all the numbers, but at the time I verified they were all the normal ones supplied as if I had bought them new).

If I need to drop down, is 40’s acceptable. The air filters and bases, linkage etc will work with 40’s and I don’t want to have to buy all that as well if I don’t need to, but would 36/38’s be a better choice?

Or

Do I get some different jets, and start going that route? I’m at a higher elevation of 3500 feet and feel like different jets may certainly help. But I don’t want to do that if the entire carb (44’s) are too big for the motor and end up chasing my tail of the starting point isn’t correct

What say you all, and thank you for any input.

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930cabman
post Sep 15 2024, 06:24 AM
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Agreed, 44 carbs are too large. Find a set of used 40 Webers and rebuild them. I would start at 28 venturi with the associated jets. Try Pierce Manifolds, they are very helpful
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