1 3/8 Headers (35mm Approx) Any Good?

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Hi Everyone,

Wanted to get your opinion on my headers.

They are originally from a crappy MOTAD system, they are only 1 3/8". But I want to keep them because they end in the right place to make a really nice tracker style system.

I was told by a guy whose opinion I trust (because he makes a living tuning 4 stroke motorcycles) that the 1 3/8" pipe was used by the manufacturer to increase gas velocity and improve performance rather than restrict it, and that the lengths are right.

Having never had a standard bike I dont know what the large pipes were like?

The headers will exit into two shorties (12")

xs1961

I used one of those Motads a few years ago ,i junked the bloody great silencer & replaced it with 2 shorty silencers on the right side,ran great,no restriction & helluva rasp!
Seemed to give the bike a lot of bottom-end/middrange,in my experiance thats what the smaller diameter pipes(1 3/8") tend to do - larger 1 1/2"-1 5/8" seem best for mid to upper end...

xs1961

I used one of those Motads a few years ago ,i junked the bloody great silencer & replaced it with 2 shorty silencers on the right side,ran great,no restriction & helluva rasp!
Seemed to give the bike a lot of bottom-end/middrange,in my experiance thats what the smaller diameter pipes(1 3/8") tend to do - larger 1 1/2"-1 5/8" seem best for mid to upper end...

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

The pipes should work as xs1961 described. The smaller diameter pipes will build torque with the mufflers. Open pipes/no mufflers will build horse power in the upper RPM's. With the small displacement of these motors, torque is critical unless you gear it down like tt does.

ttmaniac · Full Member Joined: Dec 22, 2006 Posts: 468

I usually run a 1 5/8th's header pipe. 1 3/4 is to big for anything less than 750cc I think. I'm sure your 1 3/8ths pipes will work out fine. What's the worst thing that can happen?

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Exactly what I was thinking TT.

Actually, to be honest, the worst thing that can happen is that it wont look butch enough Smile

Thanks for your replies guys Smile

Seems like you did exactly what I am trying to acheive Lee, where did you get the shorties from ?

xs1961 · Last edited by xs1961 on June 8, 2007, 4:59 pm; edited 1 time in total

I used a couple of short reverse-cone megas mate, got em new from Banbury auto jumble at £40 a pair made by Brituro..Lots of companys here in the UK stock them cheap...make sure you go for the short ones though with the removeable alloy end cap..

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Man,

Got any web addresses.

I cant find any online addresses for people offering this stuff.
One place offers for twice the US prices Sad

xs1961

Ooops...that was meant to read £40 not $$'s

What Happened to 650rider.com?

Yamaha xs650