Modern Vespa

Hi. I removed the variator to check the oil pump drive belt. After putting everything back together, the scooter no longer runs properly. It starts and idles fine, but chokes/stalls when I give it throttle.

From what I can see, the belt sits deep near the variator axle (front pulley) and far out at the rear near the clutch. The stalling seems to begin once the belt starts to tighten at the front pulley. It also looks like the belt pulls in at the rear, but maybe not completely in toward the clutch shaft.

For the record, I don't have any leftover parts, so nothing seems to be missing. I'm also confident that the rollers and plastic guides are installed correctly.

Has anyone experienced something similar or have any ideas on how to fix this?

I think that you may have not inserted the belt deep into the clutch pulley on reassembly. That means that the front pulleys are not in the correct position. You may have pinched the belt at the front pulley when tightening it to torque specs. When you tighten that front nut, you need to make sure that you can move the belt around in the front driving pulley.

PS Don't run the engine without the transmission cover.

You really shouldn't run it with the cover off. There's a bearing in the cover that keeps the clutch shaft in place. Does it stall when the cover is in place?

Thanks - Puting on the transisioncover, and also the airfilter with cover, did it
Thank you guys for helping me out
Br Dressing