Does anyone know a secret or hack to an easier 
way to put the air box boots on these bikes. I can rebuild 
a carburetor in less time than it takes to get the carburetor to air box boot back on. It’s always a pain. Maybe one of
you have found a less time consuming way. I’ve tried
loosening the air box, lubeing the ends of the boot.
I dread putting that thing back on whenever I have to
take a carburetor off one of these bikes. Thanks for
any advice.

is yours all hardened?
short of replacing it, I have found that putting it into hot water immediately before trying to install made it 10X easier. I have a tap on kitchen sink that puts out nearly boiling water from a little electric tank for making tea that's probably 200F. Silicon spray has also helped

I have just replaced the one on my Dt 360, took the carb off and pushed that end on then pushed the rear on the best I could. The part that did not seal I took a small flat head screw driver and used it to finish putting it on. I hope this makes sense.

Makes since. Thanks for your help

Bought a new reproduction. Thought it might be more flexible that old one but it wasn’t. I will definitely try your advice 
by putting it in some hot water. That sounds like a
good idea. Thanks for your help.

I had similar issues especially with the spring keeper used. Saw a recent video where the boot was installed on the air cleaner outside of the airbox then slid into the box and onto the carb afterwards. I've not tried it myself but it seemed to work for the person who made the video.

A gentle heat gun or a broken hairdryer will also soften the rubber - I use Gr8auntiepat's old hairdryer  (it's many years since I've needed a hairdryer )! 

Thank you for your help 

Thanks, I’ll borrow my wife’s hairdryer and try it.
I don’t have enough hair left to need my own .

 

There is a crease where the spring goes. I don’t use that as a position. Remove the air filter from the air box and turn it upside down on the bench.

Connect the air boot to the air box. Firmly press the boot all the way down on the air filter. No gap whatsoever. Then mash the spring to the lip of the air filter. Now it is flush and set. 

Install the connected air filter and boot to the air box. It’s set. Gently attach it to the rear of the carburetor using your thumb to crease the boot. Make certain the rear carburetor clamp screw is facing to the left at the bottom for ease of compression.

Yes, the oil tank needs to be removed out of your way.

A new boot does not need hot water or a heat gun to soften it, that’s why you bought a new boot.

a