When the engine is cold 5-10°C / 41-50°F, then for the first kilometer or two it feels like it skips an ignition or two here and there... Almost feels like when you are about to run out of gas and the engine starts skipping a beat here and there.

It starts on first try within 2-3 rotations, so that is fine and I can run it for hours and have no issues whatsoever, except for the first minutes of running. If it's a bit warmer outside (+15°C / +60°F) when starting the engine from cold there is no or very little issue.


I use full choker when starting and for the first few minutes, which helps compared to if I push it in right after start...


Any ideas on what may be going on... Could running too lean result in symptoms like this?

All four bikes I have had, has been with carburetor so I am familiar with that.
However, this feels more like if there was no spark at all from the spark plug on some strokes while cold, but not sure if I somehow can check the power  of the spark myself.
Prior to the renovation of the engine I cannot recall it doing this.

This last winter, I had similar issues.  Adjusting the idle mixture just a tad richer helped a little.  I also found myself pulling the choke out at idle, and pushing it in above about a quarter throttle.  This was an old technique I learned when cars still had choke knobs before the "automatic" choke.  Your results may vary.

If you're not old enough to remember tires being flat on one side on cold mornings, you are excused for not understanding how a carbureted engine acts.

justin_o_guy2 wrote on 05/16/17 at 19:06:55:


We used to have a van for the survey crew when I worked for the City of Fort Thomas - a work van with no interior or paneling in the back....just metal bodywork.  The back tires were snow tires with nylon cords, and the van would sometimes sit for weeks and not be driven.  When it did sit for a while - the next time we drove it the ride sure was a loud and bumpy for a while!