MP3 250: Removal of the evap canister and roll over valve
The evap system on the MP3 is not part of the original design of the scooter. It is added on all bikes destined for North America to meet a single state's emissions standards. There are various reasons you may want to remove it including:
To make more trunk space.
To fix known issues to engine performance from a clogged system.
To enhance performance. (some claim performance boosts after removal).
To remove negative or positive pressure in the gas tank.
Tools Required
Standard metric socket set with ratchet drive
A medium and large Phillips screw driver
Parts Required
Silicon sealant
A plug for the intake hose (screw or bolt just slightly larger the the inside diameter
A small hose clamp
1. Remove the rear most piece of plastic directly under the trunk lid by removing the 4 screws indicated by the red arrows.

2. Remove the right rear tail light assembly by taking out the rear screw, sliding the unit out and unplugging the wire connector.

3. Remove the two screw indicated by the red arrows on the front and rear of the fender and slide it back slightly to unhook the tabs.

4. Inside the trunk, remove two nuts front and rear (rear one pictured) from the evap canister cover and remove.

5. Either cut the two hoses going to the bottom of the canister or remove the clamps and pull out.

6. Push the hoses out of the two holes in the bottom of the trunk.

7. One of the hoses (green) goes to the roll over valve and then to the gas tank. The other (red) goes to the intake manifold. Remove the one way valve on this hose. (note: if you confuse which hose is which simply start your scooter and the hose with suction is the intake hose).

8. Circled in red is the roll over valve. Unhook the green hose (from last pic) from the valve and also unhook the hose that goes to the gas tank on the other side of the valve.

9. I chose to remove the roll over valve by pulling it under the rubber holder but you can leave it in place if you like.

10. I replaced the roll over valve with a simple large size inline fuel filter to keep dust out of the tank. Some just leave the hose open and others use some type of small air filter.

11. This shows the inline filter connected to the tank hose and then the left over hose that came from the roll over valve. I pushed this hose back through the frame so it vents down in front of the exhaust pipe.

12. The remaining hose. (red from step 7) is the hose that goes to the intake manifold. I plugged it with a screw that was slightly bigger that the inside diameter of the tube, put some silicone sealant on the threads, and put a hose clamp on it.

13. Intake manifold hose plug installed and hose zip tied out of the way

14. Evap canister and roll over valve removed

15. Put all parts back on opposite of removal.

Related Information
Article originally contributed by stickyfrog
Last Updated Sat Jun 05, 2021 5:57 pm

All Content Copyright 2005-2021 by Modern Vespa. All Rights Reserved.

Modern Vespa is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

Shop on Amazon Smile with Modern Vespa

[ Time: 0.4025s ][ Queries: 8 (0.3781s) ][ Debug on ][ 209 ][ Thing One ]