big bore

wicked6

Member
Nov 3, 2010
39
0
32
se WI
Hi guys, I picked up an 04 blaster with some mods already done to it. The first owner modded it an I am the third owner. I was told it had a big bore kit on it. is there any way to tell from the outside if it really does. This is my first quad so I am learning as I go.
 
Ken O'Connor has a video on youtube somewhere pointing out all of the differences in cylinders from big bore to stock. Check it out and see if you can find it. You will either have a stock cylinder with stock sleeve, stock cylinder with big bore sleeve, Vitos big bore cylinder, or LA big bore cylinder. If you have the stock cylinder, look at the piston to see what size it is and that should tell you if it is a big bore or not.
 
Looks fairly stock to me...

It's possible someone installed a "sleeve" big bore kit or painted a vito's BBK black. It's certainly not one of the other brands...

How's the compression on it? Have you ever taken the cylinder head off and check out the condition of things inside?
 
No I have not. I have only checked over for general maint. I should be able to tell if I took the head off right?
 
If you remove the head, you can measure the bore size with a caliper.

Stock cylinder bore is 66mm but can be bored .25mm per step a maximum of 9 times for a total of 68.25mm.

"stock" big bore size is 72mm and, depending on the brand of piston bought, can be bored 3-4 times in .25mm or .5mm steps up to 73mm.
 
Probably wont get to it for another week yet but at least I have some info to help me out. Thanks.
 
Unless you are going to "do" something about it, don't worry about whether it's a big bore or not until you need a set of rings or a bore job.

As long as it runs good, keep on ROCKIN!