L20b exhaust port inserts?

[nathan_454]

Hey guys I picked up a 1980 720 with an l20b a couple weeks ago and have had lots of fun tinkering with it... Ive got it apart waiting for a header and Weber carb, and noticed that there is round sheet metal like inserts in the exhaust ports? what is the purpose of these and can they be removed. I have never seen anything like this before... thanks in advance!

[Jester]

They are a pain in the butt to take out. Not worth the effort when there are heads out there without them.

You might try the search feature. You will find plenty of reading on the subject.

 

Welcome to Ratusn.

[nathan_454]

i searched and didnt come up with much. are they like exhaust restricters or what?

 

 

They are a pain in the butt to take out. Not worth the effort when there are heads out there without them.

You might try the search feature. You will find plenty of reading on the subject.

 

Welcome to Ratusn.

[datzenmike]

The metal liners are held away from the port walls and will get glowing hot from the exhaust. Any unburnt gasses will be ignited by this. They really don't affect performance on a street motor but if you want them out you will have to remove the valves first. I did a W58 head before. I used a 6" chisel and split lengthwise in 2-3 places and rolled them into the middle of the port and pulled them out. Yeah, sounds real easy. First one took 45 min. last one about 15.

[nathan_454]

thanks doesnt sound like i will gain anything from removing them.

[motavated]

HAHAHAHAH! I was thinking of removing them on this head i have. Glad I didn't!