Hi there, yes it is possible, I should know I have been doing the research and am currently going through the process myself!

One Yamaha dealer I spoke to said they would fit the official Yamaha part, which consists of some kind of washer arrangements. They wanted �63 for the kit (part number: kit-xt660-25-kw), and around �55 for an hours labour. However they did not have the part in stock, and said the distributors said it would take around 3 weeks to get it........I was certainly NOT prepared to wait that long till I can ride this beast lol.


Other independent bike garages said that they would fit the fiinternational kit (part number 05-DM01-K25) as seen on the website: http://www.fiinternational.com
/ShowDetails.asp?name=XT660X&type=

The actual prices for the kit varied from garage to garage, from �150 through to the full price as shown on the website of �172.99, and each garage would charge an hours labour, so around �50.

The fiinternational kit is a metal bracket on the throttle slide on the gear selector side of your bike, preventing the throttle from being opened all the way up (or so I have been told by fiinternational themselves when I rang them up).

So yes it is possible, and will cost you around �200-�250.

Hope this has helped!

Harry


p.s. you may have had more responses by using a topic title like 33bhp restriction, as 'dyno help' doesn't really describe what the question is about