Gilera Runner 70cc

I want to buy a Gilera Runner SP, but almost every Runner has more than 15k km. Is 15k too much if I want to put a 70cc sport kit (DR EVO, Stage 6 Streetrace,...) on my bike?

 

No not really. if it’s been run on good 2stroke oil

I’m in the middle of doing a midrace 70 on a runner with 22000 miles on the clock when I took it apart the old barrel and piston looked fine

 

Is the crankshaft still good for a 70cc?

 

If you don’t push it too hard yes, depends on what 70cc kit it is though

 

Mine is midrace kit so the old crank Won’t be strong enough

 

How much does a good crank for a 70cc sport kit cost? Will I be able to replace it myself?

 

I Haven’t got a clue! my crank was £140

 

Most of the standard cranks will be ok with a mid-race 70 kit, as Sam said above, it depends on how it's been treated in the past.
With the top end off you can check the play in the conrod sideways movement, if it's too excessive then replace it before you fit the new kit.