I was wondering about doing that bellmouthing mod to. Like you say there isnt much contact area anyhow.

When you say bent the reed valve how did you do this. I found when the reed stop was bent to where it clamps out on the end like you did it held it to the plate pefectly without having to put a bend in it anyhow. Pressure will also help it seal.

All of my tests have been with a 12.7 mm carb. i really would like to find a 11.11 mm carb to do a comparision. I am temperarily out of money so it may ba a while on this test.

When i did the experiment on modifying the backplate i used a common polyureathane resin that i got at autozone. there was some left at the end of the pour and it set up in the mixing cup. I really like those plasit cups for mixing this stuff when it hardens it pops right out and you can mix another batch in it again. anyhow i poped out what was left and i had this nice little plug. Wondering if it was gas proof i placed it back into the cup and covered it with gas and let it set overnight. It was totally unaffected by the gas. i think this resin is gona work wonderfull for backplate experimentation. I was gona try and do my final backplate modification this week. I may take a small break from posting for a while so dont get impatient. my wife is getting a little peeved how much time im spending on this post and on the computer as we only can get dial up out here. Besides i want to post my backplate modification procedures and testing all in one shot so it makes more sense anyhow.

Here is a pic of the resin puck after a nights bath in gas