Atlas Header pipes

possm

possm

Joined
Jul 3, 2009
Messages
891
Country flag
Hi Guys I am restoring a 1966 Atlas and I note looking through the Roy Bacon Norton Restoration book that period photo's appear to show the Atlas (and 650SS) with 1-1/2" diameter Header pipes. I note that Andover, Armours Feked etc only offer the 1-3/8" alterative, I am aware that the Commando came out with 1-3/8 pipes std, is there an advantage in either? I think I prefer the look of the 1-1/2 pipes though am unsure who supplies a quality set.

Thanks Al
 
I believe U.K. home market bikes came with 1 3/8 pipes, while U.S. export bikes came with 1 1/2 pipes. Their seems to be a consensus that the bikes run better with the smaller pipes...don't know from personal experience, but I prefer the smaller pipes.
Mike B.
 
Thanks Gilesy, I made the mistake of buying a set off RGM when I restored my 650SS, didn't even look like fitting, had to heat bend and re chrome, I complained to RGM as I am half a world away and of course "they had never had a problem before".
Al
 
Well as they all say “bigger is better” who?
That’s why all tuners go big on exhaust pipes now days and I think that’s why the Atlas came with 11/2 pipes
I ran fat pipes and later Comando pipes on my Atlas, the bigger exhaust pipe gave me better juice
nortonmark
 
Americans like fat pipes. Fat pipes exude the illusion of power. That is likely the reason the Atlas came with 1 1/2" pipes in the US market.

The 1 3/8" pipes may (may means I do not know for sure) provide more torque at some particular rpm .... that is, they are tuned.

Honda solved the problem of skinny, but tuned pipes, and made them attractive to the American market, by putting the skinny pipes inside larger ones. That solved the blueing problem as well.

Slick
 
For the 750 I would be inclined to use stepped pipes, 1.5 at port, tapering down to 1.375 –at silencer it goes up to 1.5 again.
 
You must log in or register to reply here.
Back
Top