# blaster boring



## xkarter (Apr 13, 2012)

Good morning, I was just wondering if anyone could tell me what the max bore is for a yamaha blaster is. The manual says 66.50mm. But I bought one and went to rebuild it due to low compression and the piston is a 66.92mm. Is this possible on the stock sleeve? Any help would be greatly appreciated.


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## NMKawierider (Apr 11, 2009)

Just my opinion but it sounds like someone has already punched it out over the factory recomendations. No, as far as I know the piston can not be larger then the bore and fit so the bore is larger then the piston already...which if it was the stock cylinder, is over its limit. Air cooled sleeves crack when they are too thin so.. I would get a new stock cylinder and piston/ring set. The Blaster is a great little machine stock. It was a Blaster that started me on this ATV Binge so many years ago.


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## ThreeSixtyCICJ (Dec 8, 2010)

I could have swore the stock bore was 68mm, because a banshee is 64 and I thought blasters were 4mm bigger...and a lot of guys use blaster pistons in their cub cylinders


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