Does the big bore 300 cause any vibration vs stock? Is bill blue 300 big bore kit the standard kawaski cylinder and piston?

 

With my Bill Blue 351 the vibration is not much different, and it doesn't sound like a sewing machine anymore!
I don't even know if he is making the smaller cylinders anymore.
There are lots of high mileage 351s now.
Go big or go home, ha...

I think Kawi does make the 300 if thats what your after.

 

I have the Kawasaki 300 piston and cylinder on my '06. I went with it because I got a great deal, and I kind of wanted to stay with the 11:1 compression ratio. It appears that the bigger bore kits with 12:1 don't seem to have any issues with regular fuel, but I just wanted the lower compression to insure no issues in some of the locations I travel to ride. I think most all the bigger bore kits are 12:1, and there doesn't appear to be any issue.

I never noticed any vibration difference between the 250 or 300 setup.

 

I did notice a slight difference, I would not go as far as calling it vibration, but you can feel the extra size piston. The engine growls a lot more when you twist that grip with the extra cc. I just imported and delivered a new stock 250 for my buddy. I could hardly beleive the difference between my modded 300 and the stock 250 Efi. Sewing machine smooth and sedate, compared to the 300 that sticks its front wheel up and roars. Bang for buck, go big bore, you will never look back.