Modern Vespa

I'm thinking about removing and blocking the SAS on my 150. I hear others have done it. I'm wishing to get rid of the farting the scooter does when i roll off and on the throttle.


Anyone have some instructions or a guide on removing and blocking it?

Are you talking about the evap system? If so hit up the wiki.

My 07 UK spec ET4 has one fitted , I just blocked off both ends of the vacuum pipes as these are what controls the SAS valve and I have no farting etc

so on this diagram where would I block the pipes? and would I just use vacuum-caps?

No, the SAS is secondary air system.

I blocked off the pipe on part no 7 , and the pipe that comes from the Y pipe on the inlet manifold , will post pics later

I'm anxiously awaiting those pics! I want to do this right! -bt

I'd like to see the pics,I bought the block off plate from ScooterWorks but could not remove one of the nuts to remove the SAS because the steel air intake hose was in the way and it was impossible to get a wrench or a ratchet on one of the nuts for removal.Someones help would be appreciated,thanks.

I plugged the hose 14 that connects to part 7 with a game piece from Battleship and reconnected it and the backfiring and popping was eliminated...looks like my BattleScoot is back in black and bad to the bone..for those about to rock...FIRE!.....no backfire...haha

Hi all! Since I looked everywhere to find out the way to remove the SAS and I couldn't find anything in detail, I figured this would be a good place to post what I've learned. I have an 08 S150 with a sito plus and 38 jet. As with any change of the exhaust, the SAS will Fart and pop upon decel. To correct this annoyance, you will have to completely remove the SAS (Secondary air system).
Step 1. Buy the blockoff plate from Scooter west or fabricate one. ( you can use the original copper gasket that is currently attached or you can buy another from scooter west.(Part 13 on brtoney's diagram)

Step 2. Remove small right side cover (2 screws in the front of the cover) this just makes it a little easier to access the 2 screws that hold the SAS Valve in place.(#2 on diagram).

Step 3. Remove Phillips head screws from fan shroud and pull cover off (#3,4 & 10 on diagram)

Step 4. Remove 2 screws from top of SAS valve (#2 on diagram) leave in place for now. Whole unit will just slide out once you remove the 2 bolts attaching the pipe to the exhaust. You will eventually pull the rubber fitting off the SAS Valve and slide it back into place. It may be easier to go in from the top on the screw that's further back.

Step 5. Remove the little vent cover in the lower front of the seat post (1 Phillips head screw)

Step 6. Using a small 1/4 inch ratchet and 10mm long socket, remove the 2 stud bolts holding the SAS pipe in the bottom of the engine next to the exhaust. ( I slid the socket on the stud and then attached the ratchet for clearance) the whole unit should just come right out at this point.

Step 7. Follow the blue hose (#14) to the top of the motor in front of the carb. Cut the hose leaving 2"-3" . Plug it using a small bolt ( I used a 6mm) and then use the little clamp to secure it.

Step 8. Slide the whole SAS unit out of the groove in the side of the fan unit. Pull rubber grommet off and slide it back into place. You can also leave the 2 screw clips that hold the Valve in place on the fan unit and reinsert and tighten the screws again.

Step 9. Reassemble the fan shroud and screw back into place. ( if you like you can clean the filter now)

Step 10. Apply permaseal to one side of copper gasket. (If using old one, lightly sand down to clean it up.) match up the holes on the blockoff plate and stick the 2 together.

Step 11. Slide one stud bolt thru the gasket and blockoff plate(with the plate to the outside duh lol) and while looking thru the vent opening at the bottom of the seat post, re thread the bolt just a few turns so you know your not mashing the threads. Slide the second stud bolt thru the other hole and do the same. Tighten both studs alternating sides until nice and snug.

There you go! No more popping and farting!