best header length

markee · Full Member Joined: May 23, 2008 Posts: 57

various postings mention optimal exhaust length of around 31-35 ".
This is measured from where joins motor to where??
If is to where muffler joins on (length of plain header pipe as in drag pipes to end of plain pipe) different muffler designs have different baffle starting point inside muffler. If say a small taper muffler with welded in baffle, length to start of baffle will be different to baffle placement in a long megaphone style muffler. So what i am asking is do different mufflers require different header pipe lengths???

nudude53 · Posted: May 29, 2009, 9:33 am Post subject: Re: best header length

In '74 the factory shortened them up by 5 inches, but it's unclear to me why.

Snap · Posted: June 13, 2009, 12:00 am Post subject: Re: best header length

I read that 32-33 inch from exhaust valve to end of header and 1.5 inch diameter was most favourable . I think it is explained in Building a better twin . Bub Pipes did the experimenting , I have been through a heap of sites lately I can not remember exactly. Confused

dpmphoto · Posted: July 3, 2009, 11:36 am Post subject: Re: best header length

go to www 650performance.com and scroll down to the link on free exhaust specs

What Happened to 650rider.com?

Yamaha xs650