Hi, my harley 45 with a M51 carb has a head scratching problem. The front plug is normal and looks fine while the rear plug is very dark, dry and running rich. I changed the plugs around with the same problem and checked the connections from the coil to the plugs. Does anyone have a solution, Thanks in advance !!!!!

 

enfield racing in CT sells a set of plastic type seals that fixes most issues like yours - - install them do nothing else and report back

 

I was told years ago, do nothing with tuning a Linkert until you have completed a successful bubble test of the manifold. Leaking manifolds will cause you endless grief. bubble test first (which will likely show the seals need replacing) then replace and test again. not until she can hold with making bubbles can you tune them Good luck, I hope the nipples are not leaking.