146cc (57mm) Bore Kit for Chinese, GPX, & YX 124/140cc Engines with Big Valve Cylinder Heads (Lifan, V2, etc):

– 57x78mm Aluminum cylinder with steel liner
– High compression large dome 57mm piston with rings, 13mm pin, & clips
– Head gasket kit

This will make a very nice difference in performance over your stock setup. Additionally, it is a very quick and easy upgrade as it does not require case boring. We found the right level of compression for increased performance while also keeping reliability in mind.  The 146cc bore kit includes an an aluminum 57mm bore cylinder, light weight high revving piston and a head gasket kit. Bolt on power!

Important Note: This kit will only work on Chinese 124 and 140cc engines with a 78mm tall cylinder  57mm stroke, and 13mm piston wrist pin. Common models are Pitster/GPX and Thumpstar but there are so many Chinese brands/models that you absolutely need to know your stroke and piston wrist pin size. Many vendors also call 120cc engines “124” so its important you get the actual specifications from your engine vendor or measure yourself.  Unfortunately, we are unable to tell you what you have based on a brand name as there are so many unknown Chinese brands.  This kit is also recommended for use only with big valve heads such as the common Lifan head with 27/23mm valves or our V2 Race Head for Chinese engines.

Installation Notes: Its very important that you use Hondabond (or similar quality) sealer on the head gasket.  Also, don’t use the original o-rings between the head and cylinder (not needed) but do use the large o-ring at the bottom of the cylinder between the cylinder and the engine case at the oil return.

OD of cylinder skirt is 59mm

For use with Lifan 27/23mm Head , Piranha YX 140 27/23mm head or Other Big Valve heads

Kit Includes:

• TBW0601 – Cylinder
• TBW0424 – Gasket set
• TBW0823 – Piston