RB250 SCOOTER SHOOTOUT MOTOR

[drunkmunkey6969]

Can I run a clubman on it? (lol)

Yes.....I reckon you'd still get 30+bhp ! Lol

[Darrell Taylor]

heres some graphs from today against yesterdays best
i then played with ignition and found an extra 1 bhp but did so on larger main jet so will try the smaller jet back in tomorrow hopefully 47.4 + 1 =48.4 but quite often u need to fuel the advance so maybe not?
still so much to try,i have different petals both thickness and weave,boyessen stuffing,more port adjustments,compression adjustments,flywheel lightening,different carbs,carb mods,intake tract lengths,plug grades and types as well as a few pipes to test and pipe tricks

then i have to start again with the 72mm ts1 version ive just finished

[Avantone]

new peak 47.4bhp

needs droping in a group 6 mate

or a streamliner

[Darrell Taylor]

both

[Steve Mac]

Darrell the Barrell strikes again it will be interesting next season to watch some Silhouettes battling it out for fastist scooter it used to be Capt Kirk looking at that graph my moneys on Eric

Cant fault your work Darell the 225 rapido classic with a 40 m Gori you did for me went to Brighton and back easily kept up with the TS Scooters we came back motoway all the way it never missed a beat 60/65 all the way back

Steve Mac

[Darrell Taylor]

fitted different ignition that picks up clean on the rev counter and got some power and torque runs done

ignition needs dialing in but in ballpark allready

[corrado]

rb225 kit bored to 72mm (not advised skirt is too thin)

long rod 116mm

std rb piston with skirt/cutout mods

I thought the RB pistons [except the RB20] were for 107 rods?

[drunkmunkey6969]

They are Martin.....an 8mm packer solves that and adds volume where needed.

[sean brady scooters]

the 116mm rod and packer plate allows a lower primary compression ratio (LPC) /more volumne in the crankcases ...hence less pumping losses and more available mixture /fuel in a position that the pipe can draw on and helps bring down the rather high primary comp ratios found in lambrettas to acceptable levels required by up to date expansion chambers ,it also helps piston speeds and reduces losses through friction ,less thrust on the piston skirts and smoother running ..

soz ,didnt mean to butt in Martin ...hopefully darrell will be along soon to answer and explain more and expand on the basics and principals as and when he gets time to respond

[Darrell Taylor]

the 116mm rod and packer plate allows a lower primary compression ratio (LPC) /more volumne in the crankcases ...hence less pumping losses and more available mixture /fuel in a position that the pipe can draw on and helps bring down the rather high primary comp ratios found in lambrettas to acceptable levels required by up to date expansion chambers ,it also helps piston speeds and reduces losses through friction ,less thrust on the piston skirts and smoother running ..

soz ,didnt mean to butt in Martin ...hopefully darrell will be along soon to answer and explain more and expand on the basics and principals as and when he gets time to respond

pretty much got it covered there sean/dan
i run a 9mm packer and a few rb base shims to get the cylinder height the tall crown piston also contributes to greater volume and longer rod lifts the piston/cylinder out of the confined case area which i like