Gs 160 stage four tune

[guygrrr]

that looks like a quality bit of kit. i fitted the scootrs version and had to dremel the cylinder out to make it fit.
with standard rings, as per johnny's suggestion, i opened up the exhaust to 65%.
intake is 150 with the cut out on the piston, transfers 123, exhaust 170.
i raised the cylinder 1.3mm to get the transfers about right, and i'm expecting the cylinder head to be a work of art to compensate for the lower compression.

[guygrrr]

i got the cylinder and head back, thanks Al!


cylinder w/ recess for the head


head was originally made to fit a p2, not any more.


unmolested us spec p2 head


gs160 head

[nicsar]

Nice one, that looks good.
Now i regret that I send away my SS head to be reworked for px piston. How stupid was that? Would have been easier to move that stud hole a bit and skim down the head a mm. Luckily there is so much SS junk around Finland that we can throw around a few barrels and heads.

So, couple of days and youll have some nice video clip of your mate shredding it?

[Fux]

Nice project! Going to be interesting to see how it goes. I have SS motor on the shelf thats going to get some kind of treatment at some point. When I was looking into this I came across this page, http://www.vespaio.net/Vespa180SS%20-%20VSC1T.htm , good pics of a scauri worked SS topend.
Also the reedmanifold prototype that Grand Sport came out with seems interesting.







"First pictures of the new GRAND-SPORT reedvalve manifold for VESPA GS160 / SS180. CNC machined and set up to use the known Tassinari V Force 3 reed valve Minarelli (Order nr: M1002).

Currently this is only a first prototype, the space is scarce, given the angles and the mainfold for the carb is still missing until now - maybe that would be a nice job for Basti MRP.

The reed valve is screwed by means of an adapter plate to the original 3 cylinder studs, no additional drilling required. For the prototype I have to cut the lowest cooling fin on the cylinder at the inlet side for 3 - 4mm, that's it.

With a reedvalve manifold it is be possible to use an available modern and improved pistons, like the PX 200 GRAND-SPORT piston. BigBore with 66.5 mm gives 208cc and would no longer be a problem! With the conversion exhaust manifold you can run a PX sport exhaust - please note, maybe you need to rework the original exhaust bracket.

The GRAND-SPORT reedvalve manifold for VESPA GS160 / SS180 was manufactured in Germany at the company MMW, thanks to Harald for their support.

Price is not yet clear, this is only a first prototype. QUESTION: Is there general interest because, feedback is welcome, thank you."

Wow! How do I get hold of one of those kits?? what carb are you thinking of using with this?