Cold starting issue Z1000J

[rickm]

Hi,
Bit of advice appreciated with a cold starting issue with my 1981 Z1000J.
Ever since I’ve had it it’s not liked to start when cold.
It will eventually fire up on choke (no throttle) after several (5-10) attempts, and then immediately runs and idles smoothly. Starts up straight away when warm, and generally runs fine and pulls strongly.
It has standard carbs (Mikuni BS34 CVs), air box and filter. The fuel levels are correct, with no leaks/overflow and carbs are balanced. The battery is good as is the spark. Plugs look a decent colour after a good ride.
The only noticeable oddity is that the starter motor (which is relatively new) can seem to struggle to turn the engine sometimes (less so with the throttle held open). I’d initially though the cranking thing was down to the new pistons and rings fitted just being a bit tight, but that is now several hundred miles ago.

As above, any pointers appreciated.
Ta
Rick

[Kwackman]

Hi,
The only noticeable oddity is that the starter motor (which is relatively new) can seem to struggle to turn the engine

Maybe worth checking the starter motor connections are clean and tight?

[rickm]

They look clean and tight, although I’ve not actually undone them to clean up. Maybe a good call

[Philippe]

Hi rickm

try to set the lever of the fuel tap on " pri " a few minutes before attempting to start the engine.
Perhaps there's not enough fuel in the carbs (evaporated).
GrtZ
Philippe

[rickm]

Hi rickm

try to set the lever of the fuel tap on " pri " a few minutes before attempting to start the engine.
Perhaps there's not enough fuel in the carbs (evaporated).
GrtZ
Philippe

Thanks Philippe, that's what I've taken to doing.
It may still be related to fuel and the enrichment circuit, but my best guess is that it's maybe a weak spark or slow cranking while on the starter motor. It's sparks fine and turns over normal speed with the plugs removed. I'm aware of the Weird George mod, but really don't want to go there if poss.
One "odd" thing, I once removed one plug to check the spark when it wouldn't start... it fired up straight away on 3 while I was testing it ! (with one plug missing, maybe helped it crank a bit quicker) ?