I have recently installed a triple set of Dellortos on a recently installed L28. The carbs are over a header, not factory exhaust. The carbs functioned poory upon proper engine temp. I have since comletely rebuilt all carbs and the setup runs better. However, I am considering constructing a heat shield that will bolt under the air horns and provide separation for the carbs and header. Or, last case go back to factory iron header. I don't see any shields on road cars. Is this not usually an issue (for people outside of Arizona)? Thanks for any light on the subject.

 

It's not typical for a header on a street car to cause fuel percolation in triple carbs, so you may want to make sure you don't have too much advance or that you aren't too lean at common rpm/throttle positions for your driving. When I fist put my Webers on, I found that at 3000-3500 rpm at about 15-20% throttle (normal cruise), that I had a lean miss, even though the car idled well and ran great at WOT. Had to richen the idle jets and readjust from there.

That said, a heat shield is never a bad idea. My race car has one under the triple Webs to keep some of the header heat off of them. A simple rectangular piece of aluminum with commonly available reflective heat barrier material on the bottom should do a good job. You can get the heat barrier in sheets from Summit Racing or anywhere else that sells speed parts.

I'm not experienced on Delorto's, so there may be someone else who knows a little more about your specific carbs and if they have any known issues like you are describing.

Mike