September 28, 2021, 12:12:32 PM

Project scooter

Started by ash, February 03, 2014, 07:43:36 PM

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I'm on a bit of a journey with this one.

I bought this back in the Autumn

Brought it home (forgot to SORN it  :embarrassed: :cry:) and stuck it up on a table to figure out which direction I want to go with it.

Now as it stands, it is an Aprillia Habana Mojito Custom 125 with a Piaggio 125 4T motor in it, and I want to get one of these (Gas Gas 321)

and splice them together...Now I may have to just fabricate a new subframe to hold the engine and fabricate a swingarm to bolt too it with twin shocks and put a 10" back wheel in there to retain as close to original look, or possibly take the front end off the trials bike, shorten the swingarm considerably, and then put in a 10" back wheel if I can retain the wheelbase.
I chose this bike as 1) I can't afford to spend £2k on a Lambretta to canibalise/customise (deadly unreliable as well when tuned), and 2) the Lambretta frames have a single spine tube running from the head stocks to the tail light, and would encourage a lot of flex which would need a lot of bracing. 3) the Aprillia has twin down tubes running under the foot board, and these will cradle the engine very well/allow another bike frame to be anchored in space frame stylee all around the engine for strength.   

I've picked up this mig welder, and have been having a practice with it for a couple of weeks now as both frames are steel, and I can make up jigs to align the two halves. I've got a very cheap source of CO2, but may move to an argon/CO2 mix to keep the temps down on the weld.

I've got an area now in the garage to practice my welding technique in and will be doing loads of this and other various bits on the trailer, and other odd jobs before acquiring the Gas Gas (hopefully later this year) and figuring how to bring them together in a deep meaningful way.

I got delivery of an auto dimming welding mask today from ebay and it really makes welding so much easier...I'd strongly recommend going for one after playing with a basic one as you can't see where you are putting the torch or follow the seam.

I've been in engineering for most of my working life, but always had mates to lean on for welding favours. The down side now is everything is acquiring a grey powdery tinge from the use of the angle grinder when prepping the work pieces.

I'll add bits to this as I progress, but I'm on a mission now to acquire a degree of competence with the welder before moving on to the next bit :)


Keep us informed - when you're done we can have project 'Ninja Scooter and Moped Rideout'!
Rear Admiral Lieutenant General Keller


thats a mental project  :huh: I love it! Looking forward to seeing the results.


I would have liked to have used a YPVS 350 but realistically, you need a whole bike to work from with the electrics, and all ancillaries.

The scoot will be geared for about 95 so it can cruise at 70 al day, and the trials engine is tuned for torque from tickover and also reliability.

If I can get it finished in 3 years I'll be doing well...will possibly go for electronic shift, or cable and grip shift like on the Lambrettas/vespas....need to keep the costs real either way, but being able to weld fabricate will keep a lot of the costs down :)


Sure it will be cool when its done.

Just seems like a waste of a trials bike right now, but I am prejudiced.

Do yourself a favour and ride a couple of trials on it before you destroy it forever, for cheap motorsport laughs I don't think you can beat it.
"Do you think God gets stoned? I think so... Look at the platypus." - Robin Williams RIP


I'll want to ride it as a trials bike to get a feel for the power delivery Dom. I don't think I'm flexible enough to do too much of it though. A 350 powervalve = £3k ish, 321 gagsgas £900 ish...and that is for a younger bike, so no contest. It is a scooter I wanted as a 2nd bike to play with so another bike will have to be chopped.


February 04, 2014, 12:55:08 PM #6 Last Edit: February 04, 2014, 01:00:52 PM by Dom1
Does it have to be a GasGas or will a Sherco 290 do the job?

Plenty of those around from £700-ish upwards.
"Do you think God gets stoned? I think so... Look at the platypus." - Robin Williams RIP


Quote from: Dom1 on February 04, 2014, 12:55:08 PM
Does it have to be a GasGas or will a Sherco 290 do the job?

Plenty of those around from £700-ish upwards.

Could be either, but I was looking for the biggest engine to stick in the scooter...a 321 sticker looks better than 290 on the side...even if they are all detuned for trials ;)

Gasgas has a steel frame as well as in understand it so could possibly use some of that instead of 100%.. may look a bit shit though so will have to play it by ear.


Probably a daft question, but do the trail bike engine charictaristics lend themselves to other bikes, scooters in particular.

The power delivery of the Scorpa 250 that I've ridden a few times is unlike anything else.  I know the gearing has a lot to do with it though.


I'm expecting the front end to be 'light' in every gear, but i can always just gear it up to tame it Hugh.

Not too sure about the rest of the styling yet...I may just make it more 50's retro style, but I do like the steampunk thing...whether it lends itself in that direction, I've no idea TBH.Gonna be a fair amount of time in the dry build stage though.


I take it the scooter is twist and go so will it convert to gear change or will the final output be to the conical drive?

I'm not very mechanically minded so please excuse.

Have one of these for when it is done :moto:


February 04, 2014, 07:01:05 PM #11 Last Edit: February 04, 2014, 07:03:30 PM by ash
All of that will be ditched Hugh.

There are a few people doing 2T twins into Lambrettas, but most are going into Scooters which were built in India by SIL (Scooters India Ltd) so strictly speaking, not Italian tin in any case..The Indian gov bought all the Lambretta tooling from Innocenti back in the late 60's and created SIL. I fancied this bike because whilst being modern, is still Itialian....I said GasGas, but if I can find an Italian trials bike with big enough cc and cheap enough, I'll be chasing that down instead.

This is work in progress from somebody who converted with 250 gamma engine to give you an idea of what I'm likely to have to do. I also chose a trials bike because the engine/frame configuration with them are much more compact.


Ah, I get the picture better now. Good luck!