Improve your Fox 19BB model engine

Project #11- Improve your Fox .19BB

Fox .19BB Specifications

Bore: .650
Stroke: .600
Disp: .199
Weight: 8oz
RPM: 17,000 w 8-4

User Manual

The .19BB was introduced in the early 1980's and represented a significant departure from the previous .19 bushing design. Besides being schnuerle ported, it incorporated a separate cylinder casting that could be rotated to locate the exhaust in any direction. In the late 80's a .25 version was also introduced and, for a few years, both were available. The .19BB was eventually discontinued but the .25BB remains in the Fox lineup.

The 19BB was powerful, but also a bit over-compressed, and tended to run hot. It was common for varnish to quickly form on the piston. A .01" shim between the head button and cylinder should help. There were also some mid-range carburetor problems caused by the design of the low speed needle. We recommend installing the low speed needle from the later .25BB engine, which seems to have a more suitable taper design. The .19BB is no longer produced, but "some" parts are still available.