too cool

ok guys, after a gooooood carb cleaning, bench sync & a vacuum gauge sync,plus perfect start up first time after a rebuild so why o why is my #4 exhaust downpipe not as hot as the rest????? valve clearance is with in spec also! new plugs & a good spark to all 4. can any one shed light on this pleeeeeese :roll: thanks in advance, Sean.

 

No or vastly reduced fuel to that cylinder. Incorrect setting of the butterfly valve or the pilot circuit is clogged on the body. Run it on choke and see if the cylinder warms up.....that draws fuel via a different internal passage. If it warms up then, well, you know the problem. (I am assuming that #4 has good compression, valve clearance checked, etc.)

 

sounds crazy but I had that problem on random cylinders and it ended up being just a little extra air going in the airbox.

But I definitely agree with chacal, see if you can narrow it down to one carb first.

when I was troubleshooting this I learned that the vacume nipple on top of the cylinder intake boots could be used as a port to spray starting fluid :wink:

 

i ran it on the choke and the cylinder warmed up perfectly,thanks alot len your a genius,sean