90cc Monster Big Bore Kit (QMB139) - Rolling Wrench

 This is our more affordable (vs ProBld) monster big bore kit! If you are looking for the largest kit on the market, this is it! It's a true 90cc. Don't let the $30 Ebay and Amazon 100cc kits fool you.

This kit will convert your 49cc Chinese scooter, Kymco Agility or anything with the QMB139 engine in it to 90cc's. The 90cc is as large as you can go with this engine. This kit is great quality (made in Taiwan) you won't find a nicer big bore kit. Remember you pay for what you get! The stock cylinder head will not fit. The cylinder head supplied in this kit is complete with larger valves and bigger ports making it a performance head. The ports are as large as a 150cc scooter.

This kit includes:

Piston

Piston Rings (not pre installed)

Cylinder

Performance Cylinder Head (Complete with big valves)

complete rocker box assembly

performance cam shaft (if you choose)

 BECAUSE THIS IS A DOMED STYLE PISTON, BE SURE YOU HAVE A HEALTHY BATTERY. THIS IS A HIGH COMPRESSION KIT.

ADD THIS CARBURETOR TO REALLY BRING IT TO LIFE! CLICK HERE

GY6 torque settings click here

Want a complete install video? Click Here