Modern Vespa

Has anyone had this problem? Sometimes when im just slowly turning the throttle the engine sort of lags a little, before it kicks in..as if needing more gas..similar to a car. A kind of chug a lug lug...usually as im taking off. But if i were to turn the throttle more generously it would just take off like a whippet! You know what i mean? probably not much of a problem as the dealer assured me today that its normal with 4 stroke engines..apparently something to go with the belt, or drive belt turning, he said its normal to get a little drag as it kicks in...any feedback on this? I was thinking it was maybe a spark plug or something, but just had my second service at 3000km and all of that stuff has been checked..

there has been a few post on here about maybe lowering the idle speed on the LX.
Some people say that if engine idles to hight there is a lapse between throttle and acceleration..

Hmmm that could be a thought! I say that because when the bike is in idle lately it sounds a bit more meatier than usual somewhat of a deeper vibration...maybe adjusting the idle may change this.

on my fly 125 ( same engine ) there is a slight lag till the engine winds up to speed
It's not as quick off the mark as my 2-stroke typhoon 125

Yes I think the bloke above may be correct in adjusting or lowering the idle speed...as i think this would rectify the slight lapse between throttle and acceleration

This is normal behaviour on the ET4 and LX leader 125. Twist and go tested the LX a couple of years ago and commented about the lag. If you read Wonder Machine's last post comparing the performance with the Honda Dylan you will get the idea.

The LX is really quite a slow machine.... fun but slow.

How many miles are on the bike?

It might be that the belt is stretching a little with use. It could be other things. How many miles on it right now?

Harv

3000km

Hi doug, I'm not sayin the lx is slow by no means. Because if i go WAT from the traffic lights i leave most scooters standing and trying their best to keep up I notice a lag only if im pulling away slowly from a parked position and just turning the throttle slowly gradually. I think its idling a little high, I noticed when stationary on idle the engine sounds higher than normal, a deeper vibration which wasnt there before..Im gonna have a look at adjusting it myself.

>EDIT< Thanks to both of you for pointing out my missing the mileage quited first of all. Sorry I missed that. <edit>

Idle is bone simple. Its the screw head you see when you take the pet carrier out. From the left side of the bike, its the screw coming up toward you on the right frontish side of the carb. Turn it either way and see if the bike spins sooner or not.

But with the weather change and use it could also be that your carb needs a little fine tuning. That particular screw is on the same left side of the carb but hidden below some emissions lines.

You'll see and elbow line coming out of about the middle left side of the carb. Just below that and and damn near impossible to spot will be the carb adjustment screw. You'll need the D shaped adjuster to get in there because dem bastiches use a D screw instead of an ordinary flat head screw. In other words, without the right tool, you're pretty much screwed (couldn't resist).

You can richen up the bike and it'll run cooler but burn more fuel. If you lean it out it'll run a little hotter but consume less. You want to find the balance of fuel consumption without running the bike overly hot. I ended up backing my carb adjustment out to increase fuel economy. At least that's what's been working on my own LX150.

I could be wrong, but I still think that once the belts wear a little they may also stretch. If that's the case then top end would also drop by a few miles per hour. But I ain't that guy. That guy's name is Greasy and he alsohas some knowedgeable friends here too. My point is my shade tree opinion is a little tuning might improve it but not to the point of eliminating it.

If I turn out to be wrong, and someone replies with better knowege then I will have learnt something too.

Hoping this gets settled by either confirmation or the right answer.

Harv

Ive lowered my idle screw...and now there is no lag The scoot seems a little more responsive and the engine ticks over more quietly than before, acceleration has been improved as there is no lag....this is how it should run as it feels like when i bought it 3000km ago.....engine is running in nicely ive also serviced it twice in this period....

NOT on a 125. We don't have the D shaped mixture screw, just a plain old slot head one. Phew!

Well that's good! Glad it turned out to be just an idle adjustment and thanks Dougl65, you guys are lucky that way too haha.

Seems I need to do more shutting up and listening lately... yeesh

Harv