Rally 200 Mix and Idle
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Enthusiast
'61 Cushman GS150, '62 GS160, '74 Rally 200
Joined: 20 Sep 2017
Posts: 74
Location: Seattle, WA
Thu Jun 20, 2019 5:55 pm quote
Hi, MV.

I seem to be struggling to get the idle right on my Rally 200. I had a gas tank leak at the fuel tap (flooded the floor board). Since I had the tank out, and disconnected the line from the carb, I cleaned the carb. Ever since then Iím just not confident itís right. The jets and carb are stock. Electronic ignition, no mods. I've done several mix adjustments, and right now it's at the standard Mix screw 1.5 turns out, and Idle screw at 2 turns out. Recently I put in a brand new plug (B7ES), and with minimal riding itís showing a dark grey on the electrode, and light fawn on the ceramic insulator tip. The scooter starts fine (2 or 3 kicks), and runs okay, but hereís whatís troubling me:

- It accelerates and reaches high rpms really quickly. Iíve barely shifted gears and I have to shift again, and Iím never ďriding like I stole itĒ and WOT. I typically only have the throttle open about 1/2 way (city riding).
- In neutral it idles at a steady rate, but not as steady as my GS. Instead of ďput-put-put-putĒ itís more like ďput-put-put-putily-put-put-putily-putily-putĒ.
-When I shift down into 1st from neutral the idle drops way down, like by half, but itís never stalled. My GS doesnít do that. Shifting into 1st doesnít change the idle at all.

Normal for a 200? Too lean? Gremlin? Overthinking it?
Addicted
'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 552
Location: Melbourne
Thu Jun 20, 2019 11:12 pm quote
"It accelerates and reaches high rpms really quickly." This sounds like a problem.

"In neutral it idles at a steady rate, but not as steady as my GS."

Probably fine?

"When I shift down into 1st from neutral the idle drops way down, like by half, but itís never stalled."

You mean when you shift to first but the clutch is still in? Or when you actually start moving in first?

Consider recording and posting a short video if you can, at least of the stationary idle issues. It would help others to tell if it sounds normal.

You've had the carb out - any chance you didn't hook the throttle cable up right, or adjust it right, after? You want to make sure the cable setup and adjustment isn't artificially holding the throttle open. I had that happen once just from messing with the routing of my cable housing. The throttle wasn't closing all the way, and suddenly the bike seemed really revvy
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