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 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? Will I have to change carb settings?

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?

Has anyone of you owned or owns a Yamaha SR? Could you describe your driving experiences? Pros and cons of this bike...

Thanks for your help!

godspeed

pics: modified and original Yamaha SR

Going with more airflow in and out is always going to improve the motor. How soon you reach the point of diminishing returns is the question I think that you're getting at. I'm not sure if a port job would be a "low profile modifications", but that would most likely help and allow your other projected mods to shine even brighter. Simply measuring the inside of the opening will give you the size of the carb.

Going with more airflow in and out is always going to improve the motor. How soon you reach the point of diminishing returns is the question I think that you're getting at. I'm not sure if a port job would be a "low profile modifications", but that would most likely help and allow your other projected mods to shine even brighter. Simply measuring the inside of the opening will give you the size of the carb.

Forgive my ignorance, but... what exactly is a 'port job'?

Nothing 'talueng' I hope!?!

Going with more airflow in and out is always going to improve the motor. How soon you reach the point of diminishing returns is the question I think that you're getting at. I'm not sure if a port job would be a "low profile modifications", but that would most likely help and allow your other projected mods to shine even brighter. Simply measuring the inside of the opening will give you the size of the carb.

Forgive my ignorance, but... what exactly is a 'port job'?

Nothing 'talueng' I hope!?!

**snicker**

Nothing like that. It's a time honored tradition of removing material in the intake and exhaust ports. It usually includes a polishing of the exhaust ports also so that the airflow is improved. Attention is paid to the cylinder head area, which is also smoothed and usually increased. Smoothing of that area reduces spots for heat to build, and helps greater circulation of the gases.