Earlier this year I started my Jubilee for the first time in many years. It now starts first or second kick. The problem I have is that if I switch off the ignition and then try and restart the engine soon after it refuses to start. The cause is wet (champion) plugs. Once I dry the plugs it will start.
What will cause wet plugs after I switch off the ignition. Both cylinders run normal and get up to temperature. I cant leaving it running long as its in the shed, I value my old lungs.
At the moment I cant get it out of the shed until I sort out the front wheels and forks.
Suggest you wait until it's properly running under load on the road, letting it idle for extended periods is probably fouling the plugs which with modern petrol happens a lot. Get a spare set of plugs to take with you and tune the idle mixture when the bike has done 10 miles or so and is fully hot, you probably have a rich idle mixture currently.
Plus I now have a hate relationship with champion plugs! Try an NGK B7ES if the problem persists.
Hi Dan, I had exactly this problem with the Navigator after I had rebuilt the carb with one of the new Viton tipped float needles and modern plastic float. The bike started and ran absolutely fine but leave it with the fuel turned on and just wouldn't start. I found exactly the same 'wet plugs' - Champion funnily enough! After much faffing about I found the needle valve wasn't quite sealing. Try as I might I couldn't adjust the modern float to cure the problem. A thinner washer under the needle valve housing to drop it a fraction and a return to the old brass float was the solution. That said I am now in the habit of turning the fuel off if I am leaving it for any time! I've also stopped using Champion plugs having experienced quality issues - I've found NGK are a far better option.
I think other threads confirm this and Nick has just reminded me.
The black plastic floats sold as puncture proof by AMAL have a flash around their centre.
The flash gets caught on the longitudinal re-enforcing strips - visible inside the float chamber when you take the cover off. On a normal LH carb the strip is at 8 o'clock position.
The fix is a bit of rubbing at the flash, or go back to your brass float.
I tried to improve things by closing the pivot hole in the float a very small amount so that the float fractionally moved away from the offending re-enforcement of the carb body.
Removing some of the black plastic seems to be best solution.