raising the exhaust port

[johnnyjarvis]

Mate of mine is having his exhaust port on his std TS1 raised/ported.
What difference is this likely to make through the rev range ?

[Adam_Winstone]

More power at higher revs and less power at low revs, often meaning that you have to fit a lower gear ratio (e.g. change from 4.8 to 5.5 :1) in order to reach the revs and power in 4th... and then stay in it under a reasonable range of conditions. That said, it is a case of the right balance of porting and set-up can really transform a motor, providing it suits the rider's riding style.

Adam

[johnnyjarvis]

Thanks for the reply Adam. As he is getting it done ive been weighing it up.
Run a std TS1, 20X47 with a close ratio box, taffspeed mk 4.
Pulls like a train in every gear and the power kicks in right where I want it.
Gonna leave mine as it is.

[Adam_Winstone]

Provided his exhaust and gearing allow him to use the additional power at higher revs then his bike will feel more powerful as he'll be able to hold it in the power and feel it go

The down side is that he will need to change up and down the box more frequently to keep in the narrower powerband. This will be most obvious when using it around town, on hilly/winding roads, and when trying to use it 2-up

There are pros and cons, with it very much being about riding style and use that will dictate whether it is a good move or not.

Adam