CMI Hot Spot
 

My CMI headers on a 525EFI have a hot spot on the #5 port. The other 7 ports are just fine. The hot spot is up near the collector. The hot spot is warm to the touch, but when you try and hold on to the tube for a period of time it get's so hot to the touch you have to let go. ( no more than 10-15 secounds before too hot too hold ).

The lower half of the tube is cold as can be. What can be going on?

Sounds like that tube is not getting enough water, or that clyd. is very lean.

Tube is cold coming out of head, gets hot only at the BEND up by the collector. If the cylinder was running lean would not the entire tube be HOT?

Yes it probley would.

are you doing this off idle????
repeat your test like @ 1500-2000 rpm and report results..

Sometimes when the pipes are manuf. the inner and outer pipes touch each other directly and @ a bend this can produce a hot spot area !

The pipe just has a spot where there is an air pocket and as soon as you raise the rpm it will get enough water flow that the problem goes away. Also if you are conducting this test while using a garden hose water supply you might not have enough volume from the hose to fill all of the pipes. Lots of pipes do the same thing and as soon as you come off idle the problem is gone. Hope this helps
Matt