Modern Vespa

Hello, I have a 250cc It's to slow to keep up and maneuver in north Jersey traffic. I have a 400 complete parts bike. I've just about stripped it. I also have the engine, harness parts from a Fuoco sans frame. I have the swing-arms and mounts. I only have the master for the 250 but have keys for the 400. a service key and a uncut master key. Has anyone done it? Any help would be extremely helpful

What's the reason to swap the engine instead of swapping the license plate? Both are kinda illegal I guess.

There are a few threads on here of folks doing engine swaps with varying
degrees of success. Its going to be a very significant project where you'll probably end up spending more money on supplies and parts than either bike or engine is monetarily worth.

As a project for fun and challenge thats fine; otherwise it might be better to look for a used Mp3 500 or wait for Kymco Cv3 to arrive in your market area. Alternatively outside the three wheel zone there is Kymco AK550, T-Max and other maxi-scooters that would give you great highway performance.

for this swap a 250 in to a 4/500 you need to change:
- a 400 /500 engine and not one of an older Beverly, X9, SR500, Nexus or Aprillia Atlantic the mounting point are different, the eyes that are on top of the engine show'n in the pic need to be on the bottom as well
since you got a parts bike you need to change see below

- a cable harness from a 400 mp3 in this case with opening sadle and trunk ecm
- a Throttlebody 400/500 with the masterkey chip you can change out the chip form the 250 in to the 400/500 so you can keep using the old keys and ignationswitch
- the swing arm of a 4/500
- the swingarm mounting brackets from a 4/500 these will bolt on to the frame
- exhaust pipe and muffler for a 4/500
- exhaust mounting bracket for a 4/500
- tacho unit for 4/500 RPM's are different
- the underseat compartment needs to be changed the 4/500 engine sits higher then a 250 it is possible to re-mold it with a heatgun. but better way is to go for the 400 underseat compartment
- a rearwheel 14" from a 400/500 with 140 or 150/70/14 tyre a 250/300 won't fit
- rear brakeline of a mp3 400/500 and caliper and caliper bracket the parking brake will fit you need only an other cable from a 4/500 it is longer

For other that don't have a parts bike and want to do this !!
When your going to use the newer throttlebody from a 400/500 ABS/ASR you need to program out the ABS/ASR part out or re fit the whole ABS/ASR system and you need to use a cableharness from a 500 ABS/ASR mp3

An other tip change the 400 cylinder and piston for the 500 one that will give you about 40 hp on the crank and 32 on the rear wheel the throttlebody will learn to give more gas and air to the engine after time

you can also buy a immitation Kess on Aliesxpres for 80,- and upload a mapping from a 500 to the 400 throttlebody i got 500 mapping added to this post as a zip

Thank you for the fast replies. I really appreciate it. I thought about just switching plate tbh. I just prefer the peace of mind of swapping . I also happened upon two part bikes for dirt cheap. I have the next two weeks off from work. It's like the stars aligned. I'm 6'4 210lbs the 250 is just to slow. I got the chance to ride a 400 and it's everything I need. I have almost 2,000 in all three. What's intimidating to me, is the front end of a the wire harness specifically. I should have it out this morning. Taking lots of crappy pictures. I think I understand what I have to do now. Thanks Maksor I'll keep you guys posted...

forgot the coolend hosese

Welp, I ran into my first snag. "rear brake line of a mp3 400/500 and caliper and caliper bracket the parking brake will fit you need only an other cable from a 4/500 it is longer.
I have to remove the rear brake cable? Is there a easy way to remove it? The 250 mounts on the right. The 400 mounts on the left. I'll cross that bridge tomorrow when I come to it.
Figured out how to remove rear brake line. Man, it had me stumped that's a good time to call it quits for the day. With a W still not sure about the left vs right mounting, or do I need both? Best to not get ahead of myself

Plugging away at it slowly but steadily. I should have and extra set of hands this weekend.Today, or for the rest of the day switch mounts. Strip the 250 wire harness.

On the right side a hole for the mount needs to be made. It also needs a washer between the mount in frame.

Well after 2 weeks wrenching, this is my progress . Today after torquing down a few things and wrestling with the throttle cables. I should be ready to try starting her. I did find out my parking brake cable is rusted solid, left handlebar switch is so brittle it needs to be replaced.

She's a runner so far everything thing works. Still have a few things to do. Should be back on the road this weekend. so in a couple days i'll post a short vid of it running.

What a journey! Thank you for bringing us along to see how it worked out and keeping notes.

thanks everyone for their imput. I'm a happy man

Incredible work! Have nice trips!

In a shockingly sad turn of events.... My bike was in a hit and run collision yesterday. While parked in my driveway, uphill and far from the road. Front end has seen better days. Talk about feeling defeated/ deflated It did start again. though it idles high and runs rough i'll post pics if a can remember to. Best I start another thread

NNNOOOOO!!!! thats just tragic, so sorry this happened.

If it was at the end of a driveway could it have been a delivery or someone going to the wrong address? Anything insurance can do for compensation.

If the frame is overall okay then perhaps the Mp3 community can help to source some parts from older parts bikes to revive it. Or you can change plans and run a naked Mp3 with minimal plastic and hack some brackets where needed.

Left front leg is bend

wow. that was exhausting just thinking about that. I would have just swapped plastics. glad you had success. terrible news of hit and run.