Hi I have been given a 150 kit for my wee 125 four stroke. Are there any instructions or videos to show how it's done.  The kit comprises off barrel and piston,  new Cam and all gaskets ans seals and new jets for the carb. My bike is a 2015.  Any info would be appreciated. Cheers 

Hi if it's the yamaha tyz 125 four-stroke engine you have. then it's pretty much the same engine as the yamaha ybr125  Air cooled engine. There is loads of videos on YouTube of people fitting 150 kits to the Ybr125 engines. 

Did you fit the 150 kit rodmac? I'm curious as to how much better it is. I have a 2016 125 model that's only done 255kms, so it's not even run in yet. 

You have a Yamaha TTR clone,  Jianshe engine. (Chinese, part owned by Yamaha).  Videos on Youtube for fitting a big bore kit.

Replace the 130 main jet in the Mikuni carb, with a 150.

Edited September 19, 20223 yr by stpauls