[jayjay]

can you tell me what size piston will be in my 138cc bbk, is it 60mm as I want to fit a v2 head and have heard this is the size of piston needed to go with this head, any feedback welcome, cheers

 

[BORN2RIDE#56]

60mm is a 143cc piston. a 138cc piston is a 58mm & Im preaty shure TB dont or has ever made a 58mm piston.

 

[twosmoke30]

They made a 134 a while back but that's long gone

 

[jayjay]

Thanks for that fellas!

 

[2wheeltyson]

actually 138cc piston was 59mm. the 134 kits had a 58mm piston and 143's are 60mm. and trailbikes never made a 138 kit.