650/X-2 how much of an overbore is too much?

[an82mustang]

I need the cylenders bored on my 650 TS and have found top end kits that are for up to 1.5mm overbore.. is that too much?? Just because you can do it sometimes does not mean that you should... also... can you get oversize rings? (.5 rings for a stock piston??) I'm going to take the cylenders in to the machine shop this week and tell them to keep it as small as possable..

 

[Matt_E]

Go with an overbore just big enough to get the cylinder smooth again

 

[kevbo]

I have used 78mm but only because I had to.