Hi all. Newbie here.

I am restoring my 1974 TY250 (I bought it new)

I would like to swap out the standard 428H chain and sprockets for a 520 size.

Is this a common modification? How do I go about this?

If I don't do this mod is there a source for standard sprockets?

I am thinking of close to original gearing of 14/52.

Thanks for any advice.

I am located in Melbourne Australia.

Hello Roger and welcome

I think you may be in luck with that one, TYtrials sell a kit if it fits yours, good people to deal with from all accounts, why not email them and have a mooch round their website.

http://www.tytrials.co.uk/trailandtrialsuk/prod_501953-Full-Chain-amp-Sprocket-Kit-TY250-Twinshock.html

Welcome Roger " no need to up chain to a 520 , its more weight, keep it light for trials