There seems to be plenty of knowledgeable people kicking about this section so here goes the techi question. I am looking to have a bespoke exhaust made for my ST2 (2 into 1) Its currently fitted with a chip from previously running Termi's and k&n, I will changing to Ramair filters. I need to know what diameter headers people would advise or have used with good results ? I have read quite a bit on the web and through personal experience know that 'big is not always best' I am also looking for more torque and mid range rather than alright top speed. I would appreciate any comments and feedback.........
I would think 45mm would be a good header size. Try contacting Mark at MADASL (he's on here) he may have something suitable and could certainly advise...
M55russ - from what you say I would say you should take the standard system, cut out the cruciform and weld in some link pipes. We have done this with SS, SSie, ST2 and ST4. If I was on the correct computer I would put up pictures of previous examples. I would not go larger than 45mm if you are after a complete new system. Something you can do yourself, local engineer or bike shop. Happy to help if I can. Dukedesmo - thanks.
Thanks for the info @Dukedesmo @MADASL Mark, I am needing a 2 into 1 system exiting on the right as I have fitted a S2R swing arm, so chopping out the cruciform and welding in link pipes is not a option. Its basically a Radical Ducati type system I am having made. Just before I go ahead I wanted to check on peoples thoughts on pipe diameter. From reading up on things 45mm seemed to be about right, but before investing I wanted to double check. In the future I intend to go down the hi comp piston route and worked heads, but I need to get it all up and running first. Will 45mm still be up for the job, your thoughts ?
To date about 50% of the 2 in to 1 conversions we've done are for S2R or S4R converted rear ends. All have been based on standard header sections (to save costs) The picture is a part built item for an ST4 engine which needed more adjusting than most for the rear section. If you start with an S2R standard header system it is even easier. Most fabricators will build a system based on imperial sizes (metric is more expencive) the closest is 44.5mm (1 3/4 inch) also the wall thichness is usually 1.5mm so the internal diameter is 41.5mm in round numbers. You can go thinner guage but avoid riding over a kerb or sleeping policeman. 41.5mm internal diameter is enough for your engine especially if you want to maintain low to mid range. Hope this helps a little.
