Big End Bearing?

Alright all!
Can anyone point me in the direction of a big end bearing, for my pk. 50 s?

Cranks are not too expensive for pks so I would buy a new one and have a go at fitting it yourself. If you are inexperienced at engine work my advice is be methodical and use a digital camera at each stage.When you come to put it back together you can refer to it. Also keep components that relate to each other in bags ie all the top end, all the clutch components etc. The haynes manual is shite for small frames so when you get stuck, stop and ask on the forum!

Sorry if there was any confusion, i couldn’t find it on the webshop.
I read my haynes manual last night an it suggests not replacing it DIY, what do you folks reckon?

a. leaving it it’s got 15,000 miles on it. The pistons scored to F***. putting the 75 kit on, with a new top end bearing

b. DIY. Which means getting flywheel an clutch puller (although i’ll need these for the 130 kit)

c. Getting it done at a reputable dealer. (as above)

d. stuff the old one an get a new crank, an going for the full 130cc upgrade £££, thus retiring my brand spanking new 75cc kit, which isn’t fitted yet.