96MM Cylinder and Piston Install, Running real bad after install Options

[DanPMan]

Just installed a 96MM piston and cylinder set into our 75 914-2.0. Fuel injection has been removed and replaced with a 32/26 DFV. Upon restart, there's a lot of backfiring both through the intake and exhaust. Runs like #$$#@%!!! with no power whatsoever. So far we've reset the carb per Weber initial set-up procedures and performed some initial timing. It idles, but hydrocarbons read at well over 8000 and the CO% was at 5 to 7%. So we're probably real rich. Probably should be rejetted...
Question.... when we installed the piston and cylinder sets, we also performed a valve seat rework (with a Neway by hand). All valves were verified to seat. Do you think the backfiring and no power condition is due to any other cause besides the carb and timing set-up?????

[Jake Raby]

Remove that carb

Grab the biggest hammer you can find.....

Beat the carb into a million pieces and throw it in the trash..

(this is to keep another soul from the same BS later)

Install a set of dual carbs, or go back with EFI.

The single Weber with its long runners and piss poor CFM rating will create all sorts of issues- I consider them absolutely untunable and throw them away weekly.

Making the engine larger has further increased the issues- the carb simply can't keep up with the engine.

All your symptoms of backfiring lead to running lean-

Working with that carb is like pissing into the wind, but I think I'd rather piss into the wind as install or work with one!