Hi All,
I want to build a underslung exhaust for my CT3, which will be primarily twisty road use, tarmac and dirt.
I've got the Yamaha Racing Tips book and it shows plans for a motocross pipe.  Does anyone have plans or dimensions for a pipe that would be better suite for my use?  Doesn't have to be anything fancy, just a rough guide on where to start for a broader range of power.

Much appreciated

 

I'd guess a motocross pipe would be as good as it gets for the riding your planning on doing. The pipe i guess would be in conjunction with porting as well, but on its own i'd think it would wake it up some.

Thanks mate.  I do plan on trying out the porting from the Yamaha book at some point.
I just wasn't sure if their motocross pipe dimensions would give a wider or narrower power band.

Hi Commando,
  I’m no help as to what is optimal for your situation, but am now in the middle of building a CT 175 with an underslung exhaust & port work both done to the original Yamaha racing tech specs. When done  - - and that’s hopefully by end of summer - - will report back if it’s successful 

from what i know "which is mostly trial & error" from making about 10 chambers for my bucket racers over the years--the shorter you make it the higher up in the revs the power will be made. So i guess their pipe you show is more for midrange & good top end. Hard to get a 175 to grunt off the bottom & still turn on up top. There's knowledgeable people on here up with the play on making pipes i'm sure, so just kicking it along.
My old RT something 360 with modded porting has a 250 race pipe that's too short & the power is like a light switch & terrible to ride with a wide ratio box.
Thinking back 40-45 years on my CT1 ride to work bike i got a new MX175 pipe through redundant stock from the importer "we used to fight over the list every few months when it arrived haha". I modded it to fit & the thing just turbo'd on right from low revs to over rev really, was crazy & recon it doubled the horses. Funny what works sometimes. Think the MX175 was a through the frame under the tank pipe but must've totally altered for my CT1.

Excellent.  Report any possible failures as well, please.