Modern Vespa

Looking to convert the new 3v 125cc to a 150cc. It looks a simple job and the parts are avaliable.

However one thing I need to get answered is will I need to change the ECU so it runs a 150cc ?


My local vespa dealer can't answer it. Anyone here done the conversion ?

I have not done the conversion - but surely you will have to either remap the ECU or replace it. Should not be difficult to find out whether the part number for the ECU for the 125 3V is the same as for the 150 3V or different.

They may well have different part numbers just because of the different mapping - even if otherwise identical.

Before buying or doing the head mechanicals, I'd get it to a friendly dealer and ask if they could try uploading the 150 mapping. What bits you order might then be dependent on the answer.

Have you got an A2 or full A licence?

If not, then that's what you need to be spending your money on first.

I have a full licence held for over 20 years.


Thanks for asking.


Do you have a licence for your high horse ?

Hi, i would be very suprised if the ecu was different, the change in displacement is so small, a gts big bore kit and new head does not require any different maps, if your looking for a bit more "pep" on that 3v engine, do the 150 cc or rebore larger if you can and add a malossi lambda emulator it will richen thing up.
Don't expect to much bang, the torque will be increased a little, you can play with the head gas flow port etc change cam profile, which will yeild more power from stock125cc.
I have not had experience in tuning this engine but i do know it leaves the factory tuned for mpg economy and not max power, so it will be set up to run very lean.
Or you can do what i do
Rebuild with tungsten carbide bearings and nos it
Cheers
Atb.

Lol Andy ... Won't be going the NOS option.

Just wanted to add a little something to the bike but keeping it as standard as possible.

From friends i have talked to in the scooter drag scene, i have not met one that has taken on a 3vie project, i think (well can pretty much guarantee) the restriction is all in the head, i know that when the 3vie was introduced it was over 1 hp down on the 2 v it replaced, but smoother in delivery.
I would find a good tuning shop (and there are plenty near you in kent) take the head in ask for oversized valves to be cut in and seated, then polish the inlet ports and gas flow the exhaust port. Forget going bigger in cc if there is only another 23cc to be had as what you will pay will not be cost effective for the gain .8hp ish. I realistically feel you could gain another 3.5 hp just by letting it breath better.
Not arm wrenching but still very useful.
Cheers
Atb

Dude was that really needed?

I've never seen you post before and so wouldn't know about your licence.

To clarify, The reason I asked about your licence was because I knew someone who modded a 125 to 190 a while ago. Cutting the story short, he had only done CBT, never informed insurance and so the police crushed the scoot as he was considered uninsured.

Maybe it's your ego which needs a crush.



Meh, don't see why I bothered.

What about all the 50cc owners that put 70 kits on them and dont tell any one,
50cc is classed as moped 70 is a motor bike
so different class,no one seems to care

If you're involved in an incident, especially where you may have caused injury to someone, you can bet they'll be interested - 'they' being the Police and the insurance company (if there is one...). Could wind up being jail time instead of peace all round.

Personally I'd be waiting to see if something bigger comes along. A 190 or 200 would rock.
But not if I lived where you do.

Hi all,
When i have made any mods to my scoots or the odd motorcycle that i have owned i ALWAYS inform the insurance company. The difference in insurance premiums is never more than a few pounds, infact its the admin fee of £30·00 to add the changes that is always the dearest!. I did fit a 125 cc engine in a et2 50cc i re registered the et2 as a 125 then insured it as a 125 cc et2, the premium was over £60·00 cheaper than the 50cc so go figure insurance premium priceing.
Any head, cam or ecu work would be neigh on impossible for the insurance or police to detect, it would take a very experienced engineer many hours to check tolerences, angles etc and that is assuming the engineer has the stock parts to hand with all the relevant data specs.
The major thing most people get caught out with is change of engine displacement, which can be detected very easily.
Common sense comes to mind
Cheers
Atb.

Another forum member has just confirmed that there is no need for a new ECU.
He has done the conversion.