I now have about 250 miles on the complete engine rebuild on my '53 Sq 4. I have already gone through 3 oil/filter changes/head re-torque/valve adjustment procedures to be on the overkill side. The bike is performing like a champ.. minimal oil leakage, smooth and consistent power throughout the range.
My only problem is with cold start. Most of the time, it just refuses to start via kickstart when cold. It seems a full kick is only good for a single revolution of the crank, more or less, and that may be part of the issue. I have had to resort to a push start down a short incline on our driveway, which always gets results. Once the beast starts from cold, even if running for less than a minute, then it is quite happy to respond to a single kick for subsequent starts. today I push-started the bike and then rode it 20 miles out to my shop to complete the turn signal installation. I had to start it a couple of times due to stops enroute.. every time, a single, leisurely kick did the trick.
However, after the bike sat in 50F degree temperature most of the day, it refused, once again, to revive itself via kick start, and I had to leave the bike and drive my pickup truck home. .
This is getting frustrating. The bike performs beautifully once started and warmed up, and the 3-position Solex "bi-starter" seems to be doing its job (start with knob full out, reduce to half position after 30-45 seconds), then full off in a few minutes.
But, from cold, that one-revolution kick just doesn't get it.
I've completely disassembled and cleaned the Solex carburetor, including the "bi-starter" (simple at best, with minimal gaskets), and have used new gaskets every time I've removed the carb-to-head manifold and carb-to-manifold. As near as I can tell, I do have the 'bi-starter" knob adjusted so that full out does give full control deflection at the device.
it just runs so beautifully throughout the range from idle to 70-75 mph after a 2-3 minute warmup, but so frustrating from a cold start.
I hope someone can give me a clue as to how to avoid asking for a push start at my next biker gathering!
As an additional input, yes, I just replaced all my HT ignition leads, have new spark plugs and points, and have very carefully checked timing for TDC at static. Also, because when hot, the carburetor drips a bit of fuel if left on the side stand, I have taken to always storing her on the center stand, and running the fuel bowl dry at idle upon shutdown.
Again, the bike performs almost perfectly once started and warmed up.. no missing, no hesitation, pulls right off from a dead stop like a freight train!