Hello ApexSpeed community. I'm pulling my hair out with an engine problem on my 88 VD. I'm using it for AutoX currently. The problem is that when it hits 4000-4500 rpm under driving load, the engine sounds as if it's cutting out or bumping the rev limiter. I have an MSD limiting the rpm to 6000, but the engine is giving me fits in that lower range. I've cleaned and rebuilt the carburetor, bumped both carb main jets to 170's, checked the float level (OK @ 1/2 way up or past the "ramp" at the front of the carb base), and increased the idle jet. I've run with the usual air jets of 165/170 and raised both to 195 but there's little or no change.
The engine idles beautifully and spools up to 6000 out of gear at rest with no hiccup whatsoever. Ignition timing seems proper. The cap, rotor, coil, plugs, and wires are new and all the ancillary ignition wiring appears to be in good shape. It has a Pertronix unit.
Any ideas to fix this anomaly? It's killing my times......
Thanks for your help!