Modern Vespa

Hi, all new to this. I've a 2005 Vespa LX50 which has been running great until September when it would bog down, engine keeps running but feels like there is too much or too little fuel.

Had the carb off, cleaned, new float and pin, new vacuum pump, new fuel hoses, new air filter, new spark plug.

I did get it kind off running ok'ish, but it would still always bog down at 3/4 throttle or if trying to get up the slightest of inclines.

Now I can't get off the driveway and i'm at a total loss, been tuning (trying to tune) the carb and when it's on the stand it runs smooth but the moment I put it under load it bogs down, yet on the stand you can rev it to your hearts content without issue.

Engine never stalls and if you stop the bike for 10 secs or so you can ride again until it bogs down, again.

If anyone has any ideas what may be wrong, I'd be very happy to hear.
Thanks

Did you change your vacuum lines ?

Hi, yes I changed the Vacuum pipe too, I've even tried Seafoam in the tank and nothing, no change.
Thanks

Deficient variator is among the usual suspects.

Sounds like a clogged main jet or a diaphragm with a hole or not seated correctly. When you cleaned the carb did you pull out the jets and run a thin wire through them then look to be sure they are open all the way?

I had a bike mechanic clean the carb, and then as the issue was still there after he tried to repair it I took it off myself and re-cleaned, to be fair it all looks good.

The mechanic I use mainly deals with Bike not Scooters and said he had no idea what it can be, except to start replacing parts which then get expensive.

It deff feels like a fuel issue and was running fine from Jan to Aug, which is when it sat for two weeks during holidays, back to work in Sept and the issue was there, just really odd, at first I though it was due to all the rain we had and that somehow it had flooded the engine, but i'd been pretty much dry since.

Someone suggested changing the Carb, but as I'm not a mechanic I don't know if I have to get the same carb or if I can just get a cheapo one for testing purposes.

Runs perfectly on the stand and I'm loath to scrap it but it at the same time it's not really worth much and I've already paid out near £200 with no fix, and with my local scoter shops closing I've now nowhere near me to take in.

Did you check that the diaphragm was working properly?

Possible ignition circuit issue . Have you tried changing the plug. Plus do you get a healthy blue spark which you can check without plug in ie a nail or something similar put in plug cap and seeing a spark jump about 4 or 5mm to earth. Had this once on a piaggio 50. Hopefully someone will come along and explain better very tired and off to bed.

Hi
I am having similar issues to this.. I know its yonks ago but did you manage to find a fix in the end?