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Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sat Oct 08, 2011 7:13 pm
by coaster
Sean, if it's not too cheeky, what it the thinking behind the additional holes in the piston/boostr ports?
Cheers
Colin
Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sat Oct 08, 2011 7:46 pm
by sean brady scooters
its all about symetry and flow ,the inlet ports on piston port barrels are offset towards the near side as you know ,and so when converting these to reed valve and cutting the boost ports in you can only do those within the existing inlet port width ,and so the extra hole on the off side of the piston feeds that port and helps make the overall flow symetrical again

Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sat Oct 08, 2011 11:38 pm
by Muppet
finger port runs close to the barrel stud; how deep can it be cut,
muppet,
Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sat Oct 08, 2011 11:41 pm
by Stokie
Muppet wrote:what pipe and carburettor are recommended for the kit; would it work with 2/22 and af clubman,
muppet
"Im not a complete idiot, Some of the pieces are missing"
You answered your own question
Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sat Oct 08, 2011 11:47 pm
by Muppet
the can it run on a standard pipe with 22 dellortnot question comes up when someone shows a fast road kit or bit of tuning just thought I'd ask to save anyone the need,
muppet,
Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sun Oct 09, 2011 8:09 am
by coaster
sean brady scooters wrote:its all about symetry and flow ,the inlet ports on piston port barrels are offset towards the near side as you know ,and so when converting these to reed valve and cutting the boost ports in you can only do those within the existing inlet port width ,and so the extra hole on the off side of the piston feeds that port and helps make the overall flow symetrical again

Ah, thanks Sean

Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sun Oct 09, 2011 2:35 pm
by corrado
sean brady scooters wrote:
af 250 rapido,s are notoriously thirsty and not that powerfull .
Never heard that before, I though they rapidly raced to 92 mph [or was that the RB?]

Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sun Oct 09, 2011 2:44 pm
by RICSPEED
corrado wrote:sean brady scooters wrote:
af 250 rapido,s are notoriously thirsty and not that powerfull .
Never heard that before, I though they rapidly raced to 92 mph [or was that the RB?]

ts1

Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Sun Oct 09, 2011 4:14 pm
by sean brady scooters
Muppet wrote:finger port runs close to the barrel stud; how deep can it be cut,
muppet,
I reckon that if your brave enough you could make the finger port approx 8mm deep on this 72mm bore but only at the rear as the barrel wall is thinner towards the front of the manifold area .
you would have to take care though cos it is really close to the stud hole.
Re: Rapido 250 cylinder reed valved with triple boost port..
Posted: Fri Oct 14, 2011 8:40 am
by Muppet
Could you do this to a piston port rapido 250; cutting holes high up in the piston to feed the extra ports so not cutting the ports right back to the inlet; wouldn't this make it more peaky for sprinting and possibly quicker than with a reed fitted,
muppet