Moto Vespa (GS) Project

[Grooveywordbender]

Not been on here for ages...hello again.

Just getting some bits together and prepping the frame at the moment....plan is to do everything myself. Not had a Vespa in years, always been Lambrettas, but always liked the styling of a GS (type)...it will have a PX engine of some description yet TBD....purists please don't hate me it's not a proper vintage GS.

Would not go back to drum front brakes so researched for ages regarding disc conversions...Conclusion: lot easier and less expensive with a Lambretta, than with this type of Vespa. Regardless: just got a Grimeca kit and PK fork conversion from SIP. Turns out after fitting I still have to trim 2cm off the top of the forks to fit the GS headset properly FFS. Expected to modify the mudguard but not the Forks. Before I go and do the deed, can someone with some knowledge confirm or not whether (cutting) is the case please, as well as repositioning the headset bolt groove.

Also I believe 190mm for the front shock to maintain the mudguard integrity, height wise. It would be a PX square fit 2 bolts at the bottom (as dictated by the disc conversion) rather than a GS type round one on an suspension post....can anyone confirm that this is also the case and perhaps point me in the direction of a where I may get a decent one please.

Oh and any horrors I am likely to face in the future...if you have done this before.

Many thanks,

Shaun.

[GLscoot]

I think the shock you want for this is the short Mallossi or BGM both expensive. There is another type of disc front end for this type of fork, Im sure Saigon scooters sell it. There is these guys,
https://www.scooter-and-service.de/larg ... sion/forks

http://www.saigonscootercentre.com/Prod ... =160&s_id=

I need to add, I bought the saigon one and on first ride it collapsed, the wheel drew out the internal bearings, I don't know if it was faulty, they did reimburse me the full amount and was allowed to keep it, so trying to get it fixed.


Vespa GS

Also had this one, but now sold on. It was the GS forks welded to the PX 20mm pivot pin. I didn't like the look very much, mudguard sits to high in my opinion.
Vespa GS150

[ArmandTanzarian]

I used the ScootRS disc conversion in conjunction with PK disc forks. It was quite a faff to be honest and various bits needed machining to fit properly. Once it was done though it worked very well.

[Grooveywordbender]

Thanks for the responses, very much appreciated.

Have bitten the bullet and ordered the BGM shock from the guys at Scooter Centre. Hope it will nor be too bulky, still in two minds whether to attach the MS for the Grimeca to the lower fork as designed or change to the handlebar mount....will be a lot going on down there?

Played with the GS mudguard last night positioning onto the PK fork conversion bit of a faff. Need to flatten some (squared) sections at the fixing points to allow more flexibility with positioning and need to fill some and drill some holes. Also "pack out" some gaps a little too in order to seat properly on the mudguard side fixing point...good 2cm away at present...ArmandTanzarian: I see what you mean.

All dry build at the moment with no immediate rush. (Famous last words).

I'll probably transfer this over to the "show your scoot" section at some stage and photo/report as I go along. Not going to be a classic rebuild more of a - "what I like". All positive reinforcement/encouragement and/or ideas welcome; only ever built Lambrettas so a learning curve.

GLScoot...scoot is stunning...really; see what you mean about forks sitting a tad high mind; that's what I want to try and alleviate if possible...nice though.

PS. GLScoot: Think we may have met outside McChuills earlier this year.

[GLscoot]

Yeh, that would have been me @ Mcchuils.


Vespa GS master cylinder


Vespa GS master cylinder


Vespa GS

This is the master cylinder I have.

I kinda like the master cylinder attached to the fork, as it fills the gap between the shock & fork.

[GLscoot]

"pack out" some gaps a little too in order to seat properly on the mudguard side fixing point...good 2cm away

No need to get too close, some plastic/rubber spacers may help as Im sure when braking, the mudguard rubbed against the shock.

Where are you 'grooveywordbender'

[Grooveywordbender]

Great phots, tidy setup on the handlebars.

"Packing" is round rubber vibration washers from a Lambretta leg shield/floor kit...ideal.

Live in the mighty metropolis that is Elgin.

[GLscoot]

Probably a long shot, but theres a guy in Aberdeen that has the red & silver GS that I built.

I would look at about 5mm of space between the mudguard and the bracket on the forks, otherwise it may look strange.

This is probably the best front disc set up.

http://scooterotica.org/forum/viewtopic ... 9&start=40

[Grooveywordbender]

Yip very nice set up. Actually bought a set of GS forks from the guy who built that scoot in the link you enclosed...Graham (cartmel808), seen Sean Brady building his Quattriini too, last time I visited Dan and Sean.

Have gone for these just now:



and this



Cut 1.5 cm off the top of the fork stem to seat the headset correctly and took a few sharp edges off the mudguard mounting bracket. Have decided not to mess around with the mudguard too much until I can position shock, brake, wheel and tyre altogether so looking at middle of next week before any further movement. Will put some phots together of the build as I progress in the "show scoots" section Mods can you transfer this thread across by any chance please.

[GLscoot]

When you get the forks in and front disc unit fitted, I would also fit the engine and check for wheel alignment. You may need to use a GS160 rear wheel.