The 139QMB scooter engine is a popular small engine used in many scooters and mopeds. In this detailed video, we break down ...

There are a number of different valve-guide seals, both from the factory and the aftermarket. Numbered from left to right: (1) a Fel-Pro Viton rubber seal, (2) a rubber Sealed Power positive seal ...

For the purposes of this article, we'll be focusing on valvetrain stability rather than valve-guide wear, which is another story entirely. See All 15 Photos. Implications of a Valve Change.

The guide is also machined at the top to mount a positive-style, 0.560-inch-diameter valve-guide seal. All of this conspires to limit total valve lift to a safe figure between 0.420 and 0.430 inch.

A Comprehensive Guide to Ball Valve Maintenance. Despite their durability and long service life, ball valves are not immune to wear and tear. Aug. 1, 2023. 7 min read . ... Established in 1974, Gemini ...

Special reamers like these are just the ticket to clean up the valve guides. Slowly slipping the reamer into the number 6 exhaust guide, the tool moved smoothly for approximately one-half inch ...

The F355’s 40-valve V-8 produces 375 horsepower and 268 pound-feet of torque. Bronze valve guides in some 1995 models wore out early enough to tarnish the F355’s reputation, and even though ...

A ball valve is a quarter-turn valve that uses a ball with a hole drilled through it to control the flow of media. The hole is referred to as the port or orifice, and when opened, it aligns with ...