Big Bore Options?
 

I have heard everyone talking about the big bore upgrade. What all is needed for this upgrade? Just the (Kit) head, pistons, & cam or do you have to change the carburetor also? I have stripped out spark plug threads on my current head and was thinking of the upgrade if I have to by one anyway. Anyone done this and how much should I expect to gain from this. Thanks.

Hi Tybic,
I did my 58.5 Big bore kit myself. I think it's the biggest you can go without having the crank case machined. I'd never taken an engine apart, so if I can do it anyone can. I did so many upgrades at once that I can't tell you the difference the BBK will make, but more CC's = more HP. If you decide to go big, make sure you have a pro machine your cases for you. EDIT: You'll need to re-jet your carb..

Where did you get your kit from? Do you have a link?

wildbob is correct the biggest bore you can go is 58.5 without machining the case. I wouldn't recommend going past 61mm bore on the stock case because the cylinder walls get way to thin, making the engine very unreliable. A head and cam combo will wake the buggy up. Once you do that then a big bore with a stroker crank it turns into a whole new buggy.

Is there anything I need to know about the different versions of the GY6 (old vs New) or will any 58.5mm head and cam fit when I go to ordering my kit. Bought my carbide used and I am guessing it is around a 2008 ASW carbide 7150 1500cc GY6 (not sure).

you shouldn't have any problems. since you are replacing the head I recommend a camshaft upgrade also.

Nice Thanks.

Plan is to do it.
I am thinking 58.5 with a A12 cam, do I need to rejet the carb or anything else?
I think the previous owner already gutted the exhaust.
Where to buy or not to buy any suggestions on that?

form what ive seen, guys buy an entire kit from ebay that comes with a bigger valve head, which has bigger ports, and upgraded valve springs, a selection of a camshaft, and comes with the 58.5 piston, rings, and jug, and gaskets. So you get the entire kit.

http://www.ebay.com/itm/SCOOTER-125C...701741&vxp=mtr

this is what I would recommend, you get ur choice for the 58.5 and you get your choice of camshaft. Also yes you are going to have to jet the carb, I would buy a pack of different size jets for tuning.