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Once the Adaptor Plates are bolted down to the main cases, and sealed. There should be no reason to take them off, ever!
The engine can be completely rebuilt with the Plates in place.All the Cylinders and Heads are machined, such that the any one
of the cylinders can be removed independently from the others.
It always annoyed me with the std Rg500, that if you had a problem with one cylinder you had to take the head etc off the one
next to it as well!
The Power valves are driven by one long shaft at the front, with the wheel on the rhs. (This alows the radiator to be moved further
back) The rear Power Valves are driven by a wheel in between the two cylinders, this is required to allow sufficient room in between
the frame spars. The rear shaft is two piece, joining in the middle the same as the std RG500. Also alows the rear cylinders to be
removed independently.

The Carb' pictures show a standard RG400/500 carburettor, with very poorly belmouthed inlet. This is rectified by filling in the end of the carburettor and remachining the entire carburettor, creating a full belmouth and increasing the bore to 31.0 mm. Air flow due to the new belmouth alone is increased by 18%. The new bore is offset upwards 0.6mm, so as not to go throught the floor of the carburettor, and to avoid issues with the slide not sealing at tick over. Oil feeds are removed and refitted, carburettors can be Vapour Blasted and Ultrasonically cleaned at extra cost if required.


Cost for the Adaptor Plates is £260.00 + vat and in stock. Clear Anodised.

Carburettor Vapour Blasting and Ultrasonically Cleaned £80.00 + vat. (set of 4)

Filling of carburettor and re machining to create full belmouth 31.0mm. £180.00 + vat.
includes oil feed removal/re fit and machining slide. (set of 4)

Machining Top Crankcase from an RG400 to suit RG500 Cylinders £100.00 + vat

RG575 Heads. The head is Machined to take O rings, the outer water jacket O ring is the same as the O ring for the Rotary Valves, the inner one is the same section. Viton 1.7mm BS037, This is the same as the Aprilia RS125, the Power Valve chamber has to be thin to allow room for it, this is 1mm section but also easily available. I've fitted 1mm rings to keep oil in Old Aermacchi's and British stuff, so it will be fine for this aplication, doesn't do a lot of work. All the studs have O rings, no need for domed nuts then.

The Squish is set at 0.85mm if the standard base gasket is used, the CR is 6.8:1, Squish Velocity will be 86ft/sec, (this is controlled by the width of the squish and the taper compared to the piston).With the Jig to do these we can now do this for any piston size, compression ratio, squish etc etc. Anything non standard I would need the piston crown radius, bore size desired CR or squish and the deck height. £260 for a pair of heads. The s.plug doesn't sit any further through than standard, as can be seen by the black area around the plug (not machined)

If your head is damaged it is an extra £20 per combustion chamber to weld repair it. and then £130 to remachine, as above.