Gentlemen, please don't weld on the slide throttle.
Welding on thin aluminum always causes it to warp.
Use hose and hose clamps to connect it to the other tubes.
We check it for flatness before we ship it.
If it is hard to move after it is assembled take it
apart and lightly sand the the slide.

http://www.rotaryeng.net/slide-throttle.html


You can also build a throttle quadrant that doubles the
travel of the throttle lever. That will reduce the force from the
slide by half. The total travel of the lever will be 4 inches
while the slide moves two inches.


Paul Lamar