Modern Vespa

This just happened, it freaked me out! Driving along steadily on a straight-away at about 40 mph on my LX150, nice 'n' steady, and suddenly I feel that I am slowing down, and pulling on the throttle seems to have the *reverse* effect. The engine was still running (idling really), however it was not enough to keep the wheels accelerating. I immediately pulled over. I sat on the berm and would gently pull the throttle and it was like it wouldn't shift out of first. Pull the throttle...gently begin to roll forward, lose power (engine still running but revolutions decreasing despite the throttle pull)....over and over. If I *really* pulled the throttle, the engine would actually konk out. Restart it...same thing again and again. Finally after about 5 minutes of this, it was perfectly normal and I rode home without incident.

I had just filled up less than 5 miles before, with 91 octane and no spill-over. The engine was nice and warm. My bike has 120 miles on it.

If this happened while going around a turn, or while trying to shoot out of a dangerous situation, it could be deadly. I'm nervous now and appreciate any insights into what may be causing this and what can stop this from happening again.

Remember, as other posters on the "Evap Hose" threads have said...

you don't have to fill the tanke with an actual "spill over" to possibly induce this.

Gas expands in the tank..so if you fill it up very close to the top, even without overfilling....a hot day, hot ride, etc can cause enough gas expansion to push gas up the spout, and into the vent hole and then into the rest of the evap emissions system. Then that starts the evap hose related problems.

You can check the tech library for Jess's post and pics of how to make it not do this.

Wow I guess that must be it, huh? I'm so new that this gas issue that I've seen mentioned is still somewhat fuzzy to me. I had put 1.6 gallons into the tank, this with the gas light on solid, and yes I could see the gas when I looked into the opening. The gas had clicked off on its own so I figured all was well ('cause the first time I filled up there was gas all over the damn place). Thanks for this insight...from now on I'll just put 1.5 gallons in max no matter what.

just pull the evap hose


[url]www.modernvespa.com/forum/topic83[/url]

A split vacuum hose will do that as well,
I had a vacuum hose that would intermittently suck gas from the tank.

The scooter would lose power when I got up to speed on bumpy roads,
The bumps would make the hose open slightly, Just enough to lose power.

I wouldn't have found it if I didn't carefully inspect my hoses.

Dave

You guys it has gone from bad to worse....the Vespa won't even go now, engine runs but no response on throttle, just dies and won't go forward, throttle pull makes it die...I looked under the hood and the evap hose had already been disconnected...the dealer must have done it 'cause it sure weren't me. I can't ride it at all now, we've probably walked along side it for about 2 miles, pulling the throttle, feeling the engine bog down, we're getting nowhere with it. Halp!!!

email sent

let us know what the outcome was. hOw'd you resolve the issue?

best of luck...

My Vespa is completely unrideable. Won't go forward at all! It sat overnight, now the same problem... Could it be the gas/evap hose thing even?

The pattern was: filled up (just fine), drove 5 miles, then it did the bogging down thing, then it got over it, drove 5 more miles, and ever since it won't go at all. Good thing we broke down close to home. It will idle, but give it any gas and the wheel won't spin and it just bogs down. I have 120 miles on it...and it's dead in the water!

The good new: fellow poster napacoach is coming by today to look it over. If it's not something simple, then I have to get on the horn to my dealer, VespaSF, and then we'll see what happens. Fingers crossed it's something simple and obvious!!

Anybody else ever have this happen??

A long shot but could the immobilizer antenna have come loose and it is not reading the key? That would prevent the engine from revving much past 1000RPM, I believe.

That's an interesting theory! That might explain its intermittent nature (although at this point it's 100% of the time). Although...when we have it on the center stand, we can rev the engine very high, however the wheel won't spin...it's so weird.

Well napacoach comes this afternoon, I'll give a full report after that. Thank heavens for Modern Vespa...isn't it neat how Vespa riders also happen to be really nice people? Maybe that's not a hard and fast rule but it sure seems that way.

Sigh, me again.....poster napacoach graciously came by our home this afternoon and took a look...my Vespa is officially dead in the water! After only 120 miles. Have had VespaSF on the horn and they say they're going to send a mechanic up, or come get the scoot....I'll let you all know how it turns out, I could not be more bummed.

Sorry about the LX that really blows. Thanks for the heads up and will be interested in what the final outcome will be. Hang in there.

I filled up my LX 150 yesterday and spilled gas all over the place. Today it started very rough and stalled repeatedly. At least I hadn't left the house yet. I disconnected the evap hose and it started right up. I guess I was the lucky one. So sorry to hear of your problem. Nothing could be worse than having all that fun come to a screeching halt so soon. I hope the problem is minor and your back on the road soon!

I filled up my LX 150 yesterday and spilled gas all over the place. Today it started very rough and stalled repeatedly. At least I hadn't left the house yet. I disconnected the evap hose and it started right up. I guess I was the lucky one. So sorry to hear of your problem. Nothing could be worse than having all that fun come to a screeching halt so soon. I hope the problem is minor and your back on the road soon!

the evap hose was my first thought
but sure enough it was unhooked

Amy's LX150 only bogs out when under load

maybe junk in the jets
maybe petcock ?
tip over valve ?

i'm sure Tom will have it fixed in no time

Yeah, I was thinking junk in the carb too.

is this something I have to watch for on my (first scooter) 73 50 special?