We recommend a professional technician install the big bore kit for you if you are not familiar with your engine and working on it. Having it installed professionally will bring peace of mind it was done properly while saving you a lot of time and headaches if you aren’t familiar with jetting a carburetor. The cost will vary greatly depending on the type of bike the big bore kit is being installed on and local shop labor rates. We recommend calling your local shops for quote. If you are doing just a big bore kit, all you have to ask them is for a quote on installing a new piston and cylinder and dialing in the carburetor. If you purchased a kit with a big carburetor kit and a cylinder head, it shouldn’t be much more expensive to install than just the bore kit (as they would have to re-install the stock OEM carburetor and cylinder head anyway).
Note: For fuel injected bikes, you will have to also ask for a quote on installing an aftermarket fuel controller and tuning it.
Installing the BBK yourself
If you are familiar with working on engines (or interested in learning) and want to install a big bore kit yourself, it’s typically not a difficult or time consuming procedure. All the TBparts.com big bore kits are installed exactly like the stock OEM parts. So, if you are familiar with changing out a piston, installing a big bore kit will be the exact same procedure only you are putting on a larger bore cylinder and piston. Once installed, then you will have dial in your jetting to make sure it’s not running lean. If you are not familiar with replacing your piston and want to learn, all you have to do is pick up a Clymer or Haynes repair manual for your model bike. They will instruct novice mechanics on how to remove and replace your cylinder and piston, tune your engine/carburetor, as well as many other repairs and general maintenance procedures. They also provide many important specifications and are “must have” manuals if you plan to work on your bike. If Clymer or Haynes doesn’t offer a repair manual for your model, you can always purchase a shop manual from the manufacturer. They will do the same thing but are typically geared more towards the professional mechanic.
Use a professional mechanic with experience
There is one important exception on big bore kits that makes installing them more complicated. Some kits will require engine case boring so the larger cylinder skirt will fit into the engine case. With these kits, complete engine disassembly is required and then the engine cases will need to be bored (recommend a professional motorcycle shop or machine shop for this procedure). If you have to disassemble your engine for other reasons, it’s a great time to install one of these types of big bore kits. One good reason would be the installation of a stroker crank since it also requires engine disassembly. Installing the crank and the bore kit at the same time will save a lot of time and expense. You also most likely will reach the maximum engine displacement for your model (and more power, of course). We only have a few of these kits that require engine case boring and they are:
- Honda 50/70cc Big bore kits that use a 54mm cylinder – 95cc and 117cc
- Kawasaki KLX110 and Z125 Big bore kits over 143cc
- YX150/160 & ZS155 Chinese Engines – Big bore kits that use a 67mm cylinder
Additionally, if the kit requires engine case boring, the product listing in our shop will mention that.