Motorcycle Repair: Hardtail......., seamless tubing, frame tubing

Question
I have a 1981 cm400c,and i'm wanting to hardtail the frame,any suggestions on what type of frame tubing i could use?  Thanx,Rudy

Answer
Rudy,

generally the tubing to use is called "DOM"
or drawn-over-mandrel cold drawn steel.
The cold process creates a high tensile
strength seamless tubing.
Most hardtails are either 1" or 1-1/8" outside diameter.
The tubing uses .075" -.120" (about 1/8") wall thickness.
Tig welding is used to join pieces and gussets
made to strengthen any weak areas.
It is important to keep the frame straight
so a jig or angle finders may be helpful.
http://photo.tcworks.net/Bobber?page=1
http://www.sense.net/~blaine/hardtail.html