Modern Vespa

ADVICE NEEDED.
Someone gave me a Vespa VBB2F*1GM13800M. with the hope of restoring it I stripping it down and realized that it had an 8"front wheel and a 10"
rear. Someone had put a 150GL engine VLAM1*078461* in it. It was frozen when I got it but I pulled the head and knocked the piston out, the bore cleaned up nicely ,could use a new piston/rings. The crankcase held kerosene overnight when I filled it up.

Any suggestions?

They're both 2 port engine cases. I think the seals may be different (not 100% sure) and the gearing. While you have it under the knife, you could swap out the gearing and build the rear hub back to an 8inch.

I'd go for 10" on the front instead.

Having done this recently, I'd recommend against it.

I'd just ride it like that for now, there's no harm in it. Except spare wheels are a pain. Handling-wise there is next to no difference.

If you really want to do something then I'm with J, change the rear. Can you take a picture of the rear brake area (without the wheel or hub), not sure how a GL is set up in that respect. I know the VBB and VBC have different backplates etc so a photo would be handy.

OK, three people three different answers! Anybody else? I've never used the forum before and I didn't expect such a quick response.

I don't really want to get into changing out gears and if I could run it as is for now that would be a good solution at least until I get into the rest of the restoration work and find out what I've got. Do you all agree that would work even though It,s a little strange?

To Jsharpe I'm curious to know what your experience was when you changed the front to 10".

Thank you all for the response,

Peter

me too. what happened Jerome?

siatamm, are you using a shorter spacer nut on the rear shock to even the bike out? or does it sit pretty level?

Vader, I never really looked that carefully, the shock mount looked stock. A 2" larger diameter wheel would only raise the body 1" at the rear axle.

Yeah, I was just wondering if it looked tall in the back, but an inch wouldn't be that bad.. personally, with a 10" motor, I'd put a 10 on front.. I just like that kind of thing.. unless it's all stock...

I like the idea of a 10" front too, It's a question of what it takes to do it.

I rode an allstate (8'' front 10'' back) with a P200 motor for 8 years with no issues at all.

Though I did change it to 10" last year only because I had a spare P fork.

Cheers

one inch taller in the rear will make a huge difference in the handling, and not for the better. It may be ok some of the time but it will not have enough rake and when you hit the brakes hard you will loose another inch in front and could get very unstable.

I'd convert the rear to 8in, it's not that hard.

Easy actually. Though it may not be cheap. You can either use a rally, gl, ss180 P series fork link (arm).

Here is a thread from a few years ago. My orange VNA has a rally link.

1957 Vespa VNA engine upgrades conversions? 10" wheels?

Sorry can't find any pictures just now, will look.

Cheers

I don't know the difference between the vbb front and a vbc (Super) but I did my super. all I had to do was change the hub, the axle and the brakes.. used the existing swing arm.

What about the final gear ratio if I use an 8" wheel with the 10" gearbox?

Did not know that, but makes sense if it'll just bolt up. Easy peasy. So why is everybody else switching forks?

As for OP's question, I suppose if it was me and my only scoot, I'd eventually go 10s after I try it as is, if it's that easy and no need to go inside the tranny. But don't throw any of the 8" stuff out, you may want to go back later, especially if you aquire a proper 8" motor or another scoot with native 10s for your main ride.

Obviously this would depend on your riding style and how good your suspension is. I seldom use my front brake, when I do, it's typically in tandem with the rear. I would always received lots of enquires about how my scooter handled/set up, it worked well for me.

It's worth mentioning that I rode the scooter around SF for years, never had an issue with the front end and we know how shitty allstate suspension is.....

There are a few members on here that rock 8", that's cool I just prefer 10"

Logically what Patrick mentioned above makes perfect sense. The reality for my scooter and how it was set up, was different.

Cheers

I'm leaning towards trying it as is. At this point I can't see getting into changing forks. I'm going to sleep on it, thank you all for your help.

Peter

Look the vbb was designed with the knowledge that it would have 8 inch . From the fender to the taillight . It just looks odd to me like when someone gets plastic surgery , for example fake breast never match the buttocks . It just has that something's not correct look .

Ok Here's the run-down on converting 8 inch front wheels to 10 inch.

If you're on a super, the swap is easy, as mentioned above. Swap the hub and axle and brakes, and you're there. This is fine because the super fork is essentially the same as a sprint/rally fork (10 inch), but set up for an 8 inch front wheel.

If you're on a vbb, there are three ways to do it.

1. Just do the same conversion as if it were a super fork, bolt on the 10 inch parts and call it down. This is pretty shitty. The VBB/Allstate fork isn't made to handle the 10 inch wheel, under heavy braking, there won't be enough travel and the wheel has a good chance of making contact with the inside of the fender, and then the fender slamming against the legshield. Don't do this. This is some back alley shit.

2. Use a PKXL2 fork, and do a disk brake conversion. Depending on what part of the world you're in, this can be very very expensive/impossible. Both the fork and the disk brake system are becoming scarce, and if you can find all of the parts you'll need to make the system work safely, you'll spend at LEAST $1000 USD, and you'll still have to rebuild the front fender to mount up to the new, larger fork.

3. Use a PKXL2 fork, and the original PK 20mm drum brakes. These are widely accepted as the best drum brake system Vespa ever made. DO NOT PROCEED WITH THIS CONVERSION UNLESS YOU HAVE A COMPLETE, FUNCTIONING PK FORK WITH BRAKES to use a donor. If you buy the bare PK fork from germany, you may think you can assemble the rest of the parts. This is incorrect. There are two small components in the system that haven't been reproduced, and can't be purchased. This is the problem I had. I spent the better part of 6 months collecting bits and pieces to have a fantastic front suspension, only to find out that I can't actually actuate my front brakes. I've had to spend a lot of wasted time and money translating german scooter forums to figure out how to modify parts from other models and attach very ghetto-looking hardware store parts just to make it halfway usable. The whole reason I opted not to do the disk brake conversion which while would have been more expensive, would have been easier, is because I wanted to preserve the classic front end of the scooter. That failed when I had to stack a half inch of fender washers on the outside of my hub.

Any of these swaps will force you to strip your fender down to bare metal and fill wholes, reshape the opening and drill new mounting points. I would avoid doing any of that unless you're doing a total frame restoration.

I can almost smell the frustration through the passion.
Good write up J.

A thing that might be an option is a GS 10" wheel for the front, it's the same style of wheel but someone else might have some knowledge here.

The rake angle changes by approx 1 degree. This is no Ducati, more like a tractor.
I went 10" on the rear of my Super and apart from the apparent change in gearing, I really couldn't say it felt different. Jimh has done the testing for you here, you can trust his experience.

Just ride it.

For all that money and effort sell your scoot buy a P series with disc and call it a day .

If you shop around you can find a vbb motor for about $300.

I've decided to go ahead and try it as is and in the future look for someone to trade my VLAM1 with the 10" wheel for a Vbb or similar 8" wheel motor.

Thanks to all esp jsharp for taking the time to respond.

Peter
Middlebury Vermont