Engine Bore

not to be a post whore
but a bbk is an actual differemt casting, that gives you the 240cc's
.40 over is just that, 40 thoasandths over the stock 195cc's, and doesnt add up to any cc's worth adding up
 
Like cause when i got my motor done. I told the guy i wanted it to be a 240. I got weico everything, piston, rings, crank, rods. So what does that engine work make it? A real 240 or no?
 
the biggest size piston you can get that will fit the stock head is a 68.25MM...and for a 240 kit the pistons start at 74MM...so if the guy said it "is" a 240 now you got the shaft
 
Not necessarily a whole new jug, there are 240 kits out there which are a sleeve kit and piston to be installed your factory sleeve.

The only way to tell if you have a true 240cc cylinder is to measure the bore size.

Stock bore is 66mm all the way up 68.25mm in .25mm increments.

Big bore kits are 72mm through 73mm in .50mm increments except for the wossner piston has a 72.25 option.
 
^^^^^^ good advise if you have the dough. The stock porting cn be finnesse'd but it won't be as good as the LA sleeve replacement cylinder 240 kit.

If you know someone who can install a sleeve and you don't mind doing a little home brew porting you can install the LA sleeve Sleeve type 240 kit and come out a little cheaper than the replacement cylinder but with the original yamaha port layout.

It's all in how much power you want to put out versus how much money you want to put in.