I could be wrong but i think you'll find Graham did mention the changing the exhaust & described it as a "but plug".
You are correct to also add 13T sprocket.

 

Oh I thought but plug was referring to the crankcase mod or something similar, no idea why I didn't think it was exhaust haha

 

What I was actually referring to is the Butt Plug in the end of the standard tailpipe, which is super thin and restrictive. One of the questions our new friendly Noob was asking for was for free mods that he could attempt himself. Changing out the Butplug is a cheap and effective way of de ristricting outflow, for free.( Plus a small fee for some tubing and a weld)
As far as exhausts go, you will pay minimum 300 + USD for a tailpipe, which sounds good, with little real benefit. The header is restricting flow.
So now replace header plus tailpipe, and you are into big bore price teritory.
Which would give you more bang for buck? A 331/351 big bore kit with modified But Plug, or a full exhaust system.

 

DG exhaust slip on is only $150. And the header thing could be argued

 

OK RockabillSlapMatt, you got me, did not realise there were real cheapies out there. And I can only speak from my limited experience and disapointments.Only 3 things gave me really noticable gains, Big Bore kit , big fat header with tailpipe and Uni filter. And that cost too much money.
So back tothe topic of a 250, looking for free or relativly cheap mods, I will stand my ground. Marcelino Mod, to rectify in and outflow, airbox and/ filter to get more in, Butplug surgery on standard muffler, to get more out, and a rejet to get you laughing.
This will get a standard 250 as fast as any that has had a couple more grand thrown at it. The most expesive part of that operation will be a 20 to 25 buck air filter, as all the rest is do-able by a fairly competent handy man following step by step posts in this forum, whilst perusing the workshop manual.

 

You are correct. And I agree 100%, my misinformation was the but plug . However, I think a $12 13 tooth front sprocket is more of an improvement over a $25 air filter. Just personal opinion.

 

Sorry I missed you in the new members page......oh wait you did't post in there. BONK!!!!!!!! LOL