SS180 tuning options?

[Fux]

My ss engine has a gs160 crankshaft, converted with ss180 rod so 12v conversion was possible. Runs really nice btw.

I got an extra SS180 barrel with the scoot and I am trying to work out what my options for more power are.

It looks to me that I could proberbly rebore my spare barrel and use a more modern piston. I`m not too smart when it comes to the nitty gritty of port timings and not quite sure how far I can take the barrel, or what the bore to piston clearence should be.

To me it seems that I could actualy use a px200 piston (Iv`e also been looking at Wisco pistons), and I think I read something about someone doing just that on MB`s old website.

Does someone remember, or know someone who has done it, who can pass on some info to me?

I havn`t done any work on vespa`s for years and i`m maybe a complete idiot as to the differences between a barrel and a modern piston not made for piston induction.

I`m thinking that I could modify and fit a Sip Road to make a good tourer. If it goes tits up, I can revert to what I already have.

[victor]

I wouldn't for the love of money touch the spare barrel you have - these are rarer than sunshine in London, and the uptake in power is only marginal.

I'm running a PX200 converted SS engine and it's quite torquey but I'm not so sure it's very much more powerful than the standard engine.

If you want more power, there is only really one way forward - get a PX engine and tune it.

The SS engine is unreliable to start with, and with the shortage in spares and non existent tuning options I would leave it as is and tune something with potential instead.

[Fux]

Hi Victor,

The spare barrel has been bored out and siezed at some time, so I was looking at a rebore and to match a piston.

I have 12v already, and the motor runs real nice.

I just want to play around with the spare, and if it goes belly up, I can easily revert back to where I am today.

Being a lammy man at heart, I want to keep my GS mk.1, piston ported so no px motor for me thanx.

Just looking for torque, and not revs. Lots of hills in my area, and my wife likes to ride on the back of the scoot too.

What exactly did you have done to the piston?

[victor]

Drilling the barrel to a second oversize is very, very, very different from drilling it to a px size. We are talking about 0.5 mm vs 10 mm.

The PX piston needs to have an additional port welded up.

Reliability most likely will decrease at the same time as consumption will go up, marginal only increase in power (i.e. barely noticeable).

Thus, I wouldn't ruin the original barrel which unbored is irreplaceable, drilled sort of worthless, but it's your call

Cheers Victor

Hi Victor,

The spare barrel has been bored out and siezed at some time, so I was looking at a rebore and to match a piston.

I have 12v already, and the motor runs real nice.

I just want to play around with the spare, and if it goes belly up, I can easily revert back to where I am today.

Being a lammy man at heart, I want to keep my GS mk.1, piston ported so no px motor for me thanx.

Just looking for torque, and not revs. Lots of hills in my area, and my wife likes to ride on the back of the scoot too.

What exactly did you have done to the piston?

[Fux]

Ok, I`ll measure the barrel and see how much life is left in it.

Cheers!

[victor]

You can get up to 6th oversize now which wasn't a possibility when mine super seized back in the early 2000s...

Unfortunately the bike isn't very adapted to tuning....

[soosh]

Fux,where do you live and do you know anyone in Swindon?

[Juan]

There used to be a 200 conversion available from Andre Baltdet or one of the old dealers anyway using a 66.5 piston from Borgo but that's purely on my pish memory. Guy on SBW will know for defineate.

[corrado]

Fux,where do you live and do you know anyone in Swindon?

Norway, it's a fair old ride from Swindon.

[Fux]

Hehe, yes as Corrado said, i`m in Norway.