Modern Vespa

Hello all I need a bit of help to point me in the right direction I've got a 2005 GT125L and I've ran into some trouble the bike will not go over 55mph no matter what I do to it it hits a limiter at 55

It's not an engine fault as ive swapped one over and it's still the same thing rollers been changed to heavier ones no difference the only two things I can believe it to be is maybe the ecu/immobiliser unit has went bad and has changed the rev limiter or can this be caused by a Leo vince exhaust with no baffle any help would be much appreciated. Thank you

2008 will be a gts not gt ..gt is carburettor gts is fuel injection, double check what it is

Sorry it's a 2005 not at home atm so it's of the top of my head

Lol no worries..just check throttle cable, spark plug, the usual things 1st..
I don't think the exhaust will affect it ,as they only make more noise lol
I don't think our ecu is as sophisticated as the gts one, anyone locally you could borrow quick just to see if that's the problem m8

I will try have a look but I doubt it and with throttle cable and spark plug it's all good, could it running rich affect it?

What was previous top speed?

O.S.

Somewhere around 65 on clocks

Back from holiday have fitted the new cdi on the first run it ran great got over 60 but ran out of space I then parked up to celebrate went back out 5 mins later pin the throttle it accelerated for about 20-30 seconds and started to engine break I then blipped the throttle couple times and kept it at 1/4 throttle seemed to run fine

Figured out that if I blip the throttle and keep it at 1/4 for a min I can then pin it for about 20-30 seconds before again it starts to bog down

Don't wanna take it to the mechanic yet as I already know their gonna charge a fortune to diagnose and fix it hoping it's something simple as a carb clean spark plug or fuel filter
Any help please

Try a stock exhaust. I used to have the same bike and I put that same exhaust on it and it made the bike worse.
I think the GT125L really needs the back pressure from a stock exhaust to work well.

Did it start when you put in the heavier rollers? Rollers that are too heavy will kill acceleration and top speed.

At what RPM? Just asking.

It's been a few days. Stick it on the centre stand and see how fast it will theoretically go. Don't aim it at the neighbors!

Yes.