Modern Vespa

Recently picked up a GT200. 2006 with 523 miles and close to mint. Spent the past few weeks changing gear oil, engine oil, coolant, etc. Also did a few cosmetic upgrades. Blacked out the legshield trim, mirrors, brake levers, new grips and weights (thanks ScooterpartsCo).

After all this I actually enjoy riding this bike more than my 2017 GTS300 Super. BUT...the acceleration is WAY mushy in comparison. It starts off really slow, then things get better as it gets up to speed. This agrees with everything I’ve read here. People seem to agree that the GT200 is capable of keeping up on the highway but getting from X speed to X + 1 takes longer. So I want to fix that.

I’ve read every 218 thread on this site. I’m hoping for some input from Motovista, Mike Holland, and caketin. Also the guy whose name starts with a C that has the Kubler cranked bike. Here are the questions I want to ask before I start putting in some orders.

1. I know I’ll get a significant increase in off the line performance if I install the 218 kit along with the Malossi head. How much more grunt will I get if I increase displacement even more with the Kubler crank? I ask this question because some people say the 218 will get me wheelies and others say it will get me up to GTS300 performance. This effort has to be worth the time, effort, and $. I want wheelies.

2. Seems the GT200 is different from the GTS bikes and the same exhausts don’t fit. If I get a Malossi cylinder and head what exhaust fit would I shop for?

3. When I do this I plan to use the Mikuni carb. With this carburetor is it possible to easily attach to the stock air box or will I have to use a pod filter?

4. I weigh 195. What rollers can I change to now that will cure some of my current off-the-line woes and what advantages would I get from moving to a completely different variator?

5. My “book learning” doesn’t extend to all the other springs on the other end of the belt. Should I be looking at different clutch and contra springs?

My priority is acceleration. I’m not as interested in going 100mph. I’d like that too but getting up to speed quickly is my main concern.

1. How's your skills? Changing out the crank is a whole order of magnitude from swapping the head.

2. Might be reading the wrong threads, my understanding is exhausts are essentially interchangeable. Minor difference in stroke length only.

3. With the Mikuni will lose the pet carrier anyway, noise aside pod will work fine and make the most power. That said should be able to make the airbox work with minor mods. See my Mikuni thread.

4. Get a tach. Will want it for tuning. For starting point general consensus is that 10% lighter works well. IMO advantage of aftermarket variator is greater range, you can get a lower "low" with out sacrificing any top end. Can do similar with the factory vario and spacer washers but will lose top end gearing.

5. Clutch only if you want revvy take off, but they're cheap if you want to experiment. Will want the contra, especially if making more power. No belt slip, accelerate up hills, downshifts better.

Thanks for the reply. I’ll go read your Mikuni thread, I’m sure it’ll shed some more light.

I’m quite handy, having built a couple car motors and even an automatic transmission. I’ve tried to tackle some pretty big jobs and like grease and torque wrenches.

Your reply did however make me want to take a more conservative path. I don’t really want to change the crank, it just seems like it would be pretty awesome to stroke the motor. The pet carrier is my only storage option so maybe the Mikuni is not an option either.

218 kit, head, rejetted carb, variator should be more than adequate, and about $1000 cheaper but I will also hope to hear from anyone else with experience and opinions on this.

Following this thread as I have the same scoot and are also interested in adding mods soon.

Just my tuppenceworth
I've got a 125 injection thats out at 218 now.
All the Malossi kit, Forecemaster 2 , clutch, gearbox from a 300 Dr Pulley sliders etc.
Also got a 300 thats pretty standard apart from an Akra on it.
The 300 is definitely slightly quicker and pulls slightly better, but the 218 is definitely more fun.
Think to get into wheelie teritory you'll need to get the Mikuni running spot on

Sorry , hit post before I'd finished
I think Caketins build is the best bang per buck available,
And, he pretty much tried and tested the permutations so anyone with a carbed 200 or 125 (over this side of the pond) has a great chance of success

Great feedback thanks for your input. It’s helpful. This project is on hold and in the meantime I’ve just been riding and enjoying it as is.