what size do big bore sleeves start for yamaha engines? and tell me about this engine

[oxnard111]

the reason I ask is I bought a ski with a supposed "big bore" engine. Cylinder is stamped 62T on the side. bore measures 83.5mm. I specifically asked him if the cylinder had been resleeved.

If they are stock sleeves that means it is on its last bore correct?

besides that, the porting appears to be all mid-top if I am not mistaken. Port height measures 36.6mm. he said it was more low-mid porting.

tell me about what type of power you think this engine can make.

 

[MTRHEAD]

You can bore them to 84mm. The bottom lip gets too thin it has a groove in it I found this out after buying some 62T cylinders

You can make 140 hp with the best race parts available in 84mm setup with the right parts. 120ish is probably more realistic with normal parts.

 

[#ZERO]

They look like stock 62T 701 sleeves and you'll be on your last bore at 84mm.

Good for mid range power but not great for bottom end.

Big bore sleeves are the same size all the way down to the bottom skirt and start at 83.20mm ID

 

[restosud]

i have one at 85mm with wiseco .bottom end porting with 185 psi and it pulls like a tractor.

 

[yamanube]

Did you buy that ski from 24/7-760superjet?:dunno:

 

[SuperJETT]

If it's a true 62t cylinder, then it's a Raider 701 cylinder that started at 81mm which is more mid/top.