I'm a bike lover and curently ride a Tiger ST200 for everyday use and a Suzuki Bandit 400 for the weekends. I'm very happy with both bikes but lately started wondering if I could get out something more from the Tiger. I did some small modifications on the estetical side and removed the air filter (just the polyester, not the entire box), which gave me slightly more torque in the lower and mid range.

I'm now thinking about about the carburator and the exhaust.
My questions are:
1) what size is the carb on the ST? How can I find out? How much more power can I expect with a bigger carb?
2) If I partially free up the silencer (I suppose there is some metal wool inside), besides getting a more powerful sound, how will that influence the overall performance of the bike?
3) What other low profile modifications could I do on my bike to get more power?

I'm not interested in top speed but in torque...

My dream would be to get an old Yamaha SR 400 or 500 and make a unique cafe racer out of it.
I would sell my two other bikes and just keep the SR. Sadly I haven't yet come across an SR with green book so far.
What are the dangers in driving without green book?
To the moderator of this website: are you going to test this bike? There is a big fanbase of the SR in Japan AND here in Thailand!

Thanks for your help!
godspeed
Mr. Mankut

One of the best things to start with, when thinking about tuning your bike for more performance, is to start with making sure that engine is correctly adjusted.

Not all engines, even if they come from an assembly line, are the same. It is therefore important, that the carburetor is correctly tuned. Carburetors on factory bikes are set to perform well on all circumstances and within the measurement tolerance to what the engine is manufactured. (Which is fine for most of the time, but it is not the best it can offer)

You need to understand that carburetor tuning is a time consuming job, but it, if don right, is most satisfying. In the section Modify & Maintenance you will find some useful articles about carburetor tuning.