Hi, can somebody advise me as to which piston is used to convert TY175 to 200. And is worthwhile. Is it just a rebore and nothing major like machining piston or whatever. Thanks.

Yes welding and lots of machine shop work are required. Yes it's quite expensive. If you have to pay someone to do the work it would cost probably more than most people would be prepared to pay for a whole TY175 in good condition. The worth of it to you depends on how you value engine performance. They go just like you would expect a TY175 that was made to 205cc ie it has about 17% more torque at the same RPM.

Speak to John Cane at Trail and Trials Uk, he has made a 200 kit and its been fitted to a bike. He will be able to tell you whatyou need to know, and how much. Contact him on 0161 288 8224.

P.S. John has a wealth of knowledge on TY's and is only to happy to share it.

Thanks.