Replacing The Floating Valve Seal

Here's a step-by-step how to on replacing the Floating Valve Seal. This seal contributes to a steady idle and crisp throttle response. Over time it can flatten and needs to be replaced. Also, carb cleaners will damage this seal. You can replace this seal with the carb on the bike. In the case of this how-to the carb was removed from the bike. Before removing the carb from the bike make sure the petcock is in the off position and all fuel in the carb has been properly drained. Perform all work in a well ventilated area away from any source of ignition.

Remove the throttle slide cover bolts

With the slide cover removed, remove the screw on the throttle linkage. CAUTION: This screw is installed with Blue Loc-Tite. The head of the screw is very soft. Make sure you use a correct sized Philips screwdriver.

With the throttle linkage screw removed you can now remove the slide. Note the orientation of the slide when removing it. There is a front and a back to the slide and you'll need to install it in the correct orientation. Also, be careful as you remove the slide as the floating valve plate will fall off.

With the slide removed note the orientation of the floating valve plate. You'll notice the hole in the plate is facing the bottom of the slide. It is a common mistake to install the plate upside down. If installed upside down it will cause a hanging idle and bogging.

Remove the floating valve plate from the slide.

Before removing the floating valve seal, note the orientation of the seal. You'll need to install the new seal in the correct orientation.

Remove the floating valve seal.

Complete the installation by installing the new floating valve seal in the correct orientation. Install the floating valve cover in the correct orientation (hole on the bottom of the slide). Install the slide in the correct orientation. Finish by installing the slide cover. When installing the slide cover apply a very thin coating of waterproof grease to the o-ring.

When replacing the floating valve seal it's a good opportunity to clean the slide and the slide runners in the carb.

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CRF's Only "How-To" By CRF's Only Staff


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