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In 99% of all cases a cylinder modification makes sense.

General
Cylinders are usually modified to improve the transfer ports, particularly to optimize flow and to adjust their cross-section at the bottom of the cylinder. The exhaust port is very important too.

Boost Port
A special case is the boost port or also support port opposite the intake port. Similar to the transfer ports the flow is optimized and size of the ports cross-section is adjusted.

Exhaust port
The design of the exhaust port is very critical. Widening the exhaust port to up to 70% of the bores diameter is typical (It is recommended not to exceed 65 % or 67 % on engines that are intended for daily use) and can increase the horsepower over the whole bandwidth. If the ports height is increased towards the top the max rpm and power will increase, but also the power at lower rpm will decrease.

Vespa Polini 177:
Exhaust port modification 177 ccm Polini - 30 EURO

Vespa Malossi 210:
Exhaust port modification 210 Malossi - 35 EURO

A very special outlet port modification is shown down in soem picturs. The Mallssi 210 exhaust Aluminium stud is cutted and Aluminium welded on. So it can be screwd on a steal flange with bigger diameter inside. Also these is no problem in the future with demaging the Alu standard stud with exhaust clips.

Modification 210 cc Malossi incl. Stealflange - 130 EURO

Scootermatic:
We port the outlet complete (milling and polishing).
Outlet port widen up Runner / Hexagon 150/180 ccm - ca. 50 EURO
Outlet port widen up 50 ccm - ca. 40 EURO
cylinder complete modifications / examples

Vespa PX 200 - Malossi 210:
cylinder 210 ccm Malossi (WITHOUT piston mod.) - 85 EURO
cylinder 210 ccm Malossi (WITH piston mod.) - 130 EURO

Vespa Smallframe Polini 133:
The cylinder for the Smallframe Vespa is shortened 3.2mm at the bottom and 1.8mm at the top. A 5mm aluminium spacer is added to the bottom. Only by lifting the cylinder the transfer ports are fully opened and the timing is improved. We also modify the transfer ports, the exhaust port and the boost port. These modifications require the modification of the transfer ports on the engine housing and if you want to have it done right we recommend adding material to the housing and making the transfer ports even larger.

139 EURO

Note:

Malossi 210 and Polini 130 can be ordered in our shop - modified !! Onlineshop

Lambretta TS1:
A extremly modification is these TS1 conversion. The main ports are welded on teh outside, so that we can mill very big ports. Even the boost port is welded close, so that we can mill to bigge rports inside the line. The barrel has to be new nicasiled. See pics down.

Price from 519 EURO

The motor casing has to be modified to (welding big ports, spindling, planning, ...)

About 165 EURO

Aluminium cylinder piston line welding higher

Where does it need ?

If you use an extrem longstroke crank (Lambretta from 62 mm, Vespa from 62,5 mm) its better to weld and modify the line higher. If not you get veryvery bad port timings. The problem is, that its not possible to get good timings with UNmodified barrels, because the piston rings comes out of the line at the top. Therefor we weld the line (only possible at aluminium barrel) higher - maybe 3 or 5 mm. After welding we rework the line and make a new nicasil liner on it. So you optimize your port timing if you use an verylongstrioke crank.

From 429 EURO, incl. new nicasil

Scootermatic:
milling bigger, polishing Runner / Hexagon 150/180 ccm - 50 EURO
milling bigger, polishing 50 ccm - 50 EURO
Following some examples of modifications.