Howto: Honda Ruckus Big Bore Kit

Honda Ruckus Big Bore

An alternative to GY6 swapping a Honda Ruckus is doing a big bore kit on the stock Ruckus motor. Though very hard to obtain parts unless you know the right people, there have been 1 or 2 kits that have popped up over the years. Be warned, a Honda Ruckus Big Bore is a very DIY mod and will require modification to your cylinder head and associated parts.

What are the benefits to big boring a Stock Ruckus GET motor as opposed to just swapping it out for a 150cc? For one, you retain all of the bulletproof mechanics of the Ruckus motor (water-cooled, magnetic starter, magnetic water pump, simple valve train, etc) that makes the GET motor so reliable and efficient. From a legal standpoint, it would still technically be marked as a 50cc motor. This may prove beneficial to some places where there are more strictly laws on engine displacement sizes and emissions testing that would classify a 150cc swapped Ruckus as a motorcycle and cause increased insurance, licensing, etc.

So how do you do it and what do you need. Well first, you need to get your hands on a Honda Ruckus Big Bore Kit....No it is not one of those $50 kits you see on eBay, it is an oversized piston and associated parts made specifically to fit the Honda Ruckus. The 58.1cc Piston Kit has since been discounted, so there is very very limited supply and availability, so good luck getting your hands on one! The piston kit only includes the oversized piston, wrist pin, clips, head gasket, and piston rings. The part that requires the work is sending your disassembled cylinder head away to get bored to fit the oversized piston. This is the part that requires specialized equipment and measuring tools to properly bore out the Honda Ruckus cylinder head. Because of this, it is not simply a bolt on kit. If time and work is put in to correctly install and build a Honda Ruckus Big Bore, it will pay itself back in terms of acceleration, top speed, and longevity.

Here is a photo of the Honda Ruckuc 58.1cc Piston Kit:

Honda Ruckus Big Bore Kit

Once you get your hands on a Honda Ruckus Big Bore kit. You will need to completely disassemble your Honda Ruckus GET motor. It will be handy to get yourself a shop repair manual for the Honda Ruckus if you are unfamiliar with the layout and inter-workings of the motor. This will also be a good time to replace all seals and gaskets. It is always good to rebuild with fresh parts, oil leaks are your biggest nightmare and can cause damage to the motor and what better way to prevent this than will new sealing components. We also opted to get a brand new stock crankshaft to aid in longevity of the motor. We didn't want to be breaking down this motor every month for repair so, now is the time to spend the time and money in rebuilding the motor properly. When you have your bare cylinder head apart, it is time to find someone who can do the bore work. A machine shop should have all the necessary equipment but we recommend U.S. Chrome for engine bore work. The stock Ruckus bore size is 37.8mm, we bored our cylinder to 41mm for the 58.1cc kit. You will need to send the new piston with your cylinder head so the machinist can accurately measure in there conditions and have the work done to spec. Once you get your bored cylinder and piston back, It is time to assemble!

Some other things to consider before installing your big bor