And the winner for the most complicated solution is...

[Jonny69]

...PIAGGIO

Damn their eyeballs! It's a 125cc moped, how complicated could they make it? I've got engine running problems which I'd normally be able to fix with a bit of fettling with idle speed, timing and mixture but oh no, not on a simple little 125. I have never seen such a mishmash of random tubes, return pipes, wires, sensors, pipes, breathers, air boxes and springs in my entire life. It's a 125 FFS, what could it need that my car engine doesn't?

The carb has one fuel feed in but another two odd pipes that go off to the engine and into the air box. Then there are three seperate wires that go in to unknown stuff, one of which has a long spike on the end of it that I stabbed my finger on. What is all this crap? It's only got to make a moped work.

Anyway I'm really annoyed with it as none of this stuff bears any resemblance with anything in the manual and basically means that I've got to put it al back together, still not working properly and take it to a shop to get it fixed. TO GET AN ENGINE THAT IS SMALLER THAN A WINE BOX THAT OUGHT TO HAVE A JUST SIMPLE CARB AND NOTHING MORE, fixed!!!

To get to the spark plug I had to drop the engine out the bike. How stupid is that setup? Well done Piaggio you stupid Italian idiots

 

[DreXeL]

Must all be emissions control crap.

 

[Jonny69]

Slowly finding out what some of this stuff does. One of the wires that goes to the carb is an electronic choke assembly and one of the pipes that goes from the tank to the inlet manifold is a vacuum operated tap for the fuel feed. I.e. when the engine isn't spinning there is no vacuum so the tap is shut. Pointless as there is a check valve in the carb for this and er, what happens on wide open throttle when there is no vacuum there? Maybe it's just really inefficient and keeps vacuum in the manifold at all times because the carb is too small.

Shame I haven't got much spare cash and time or I'd strip all that crap off the engine and replace it with a simple little Malossi carb or something.

The big fat pipe from the head to the airbox is a block breather by the looks of it but I really can't work out why the engine doesn't run any revs if you disconnect it. It idles ok but if you open the throttle it stumbles and stalls. Makes no sense to me and I have an overwhelming urge to SIMPLIFY it.

 

[Puzzled]

Any chance of cramming a V8 in there?

 

[Jonny69]

One of those model V8's would be ace. Like this one: click

 

[Jonny69]

So looks like one of the wires going in there is a carb heater. I'm really thinking about ditching this lot for a simple straight through carburettor. All this complicatory just leads to stuff going wrong and then not being able to diagnose it.

 

[Dr Who]

Slowly finding out what some of this stuff does. One of the wires that goes to the carb is an electronic choke assembly and one of the pipes that goes from the tank to the inlet manifold is a vacuum operated tap for the fuel feed. I.e. when the engine isn't spinning there is no vacuum so the tap is shut. Pointless as there is a check valve in the carb for this and er, what happens on wide open throttle when there is no vacuum there? Maybe it's just really inefficient and keeps vacuum in the manifold at all times because the carb is too small.

Shame I haven't got much spare cash and time or I'd strip all that crap off the engine and replace it with a simple little Malossi carb or something.

The big fat pipe from the head to the airbox is a block breather by the looks of it but I really can't work out why the engine doesn't run any revs if you disconnect it. It idles ok but if you open the throttle it stumbles and stalls. Makes no sense to me and I have an overwhelming urge to SIMPLIFY it.

The vacuum fuel shut of is required so as to prevent excessive evaporation in the carb opening the fuel flow amongst other reasons..

All bike engines have a fuel tap/shutoff of some description, be thankful yours is automatic



Why are you so worried about changing it?

 

[Jonny69]

Not so much I'm worried about changing it. I'm sick of it not starting, stalling and idling badly basically because what they have put on there is way over the top for such a small engine and for me an older bike would be more reliable as I'd be able to get it going on the roadside, not get stranded somewhere.

It's almost like a car engine in the late 80's. The manufacturers were trying to be too clever with complicated fuelling and ignition systems but all it did was result in engines that would never start in the morning and were impossible to tune at home. This is a 1960's/70's engine with loads of extra stuff stuck on it and it's just made it unreliable. At least on the older engines you could get it running again when it died. This one just does what it feels like which is really irritating