Aprilia RS50 9 Pipe Test, the results page!

[RpR]

If 15000+ rpm isn't harmfull for a 39mm stroke engine, then i don't understand why noone utilizes this when tuning small two strokes.
Not even the very powerfull Polini EVO kits for scooters rev that high, and they make over 20hp at the rearwheel, loosing at least 25% in the variomatic.

[ip2]

more rpm past peak dont allways mean more peak HP , in fact its just the oposite

kart can make more power with narrow range pipe that doesnt rev so high .. but they dont have gearbox so they have to have very wide band and need to rev very high to gain speed ,
karts go from 15000 to 20000 rpm in few seconds while RS pipe hit the wall at 15000 rpm and you shift , kart cant shift cause there is not any !

look at the graffs , the pipe that make best peak power dont rev past peak , usually fat pipe with short end cone are like that , skiny , short pipe let it rev higher but make less peak power than fat ones

all the pipe do is take power from one area of band and put on another area , of course higher areas = big power, and no pipe can make power below 10000 like stock

scooter race pipes are more peaky than Rs pipe because they can use narrower band , some peak at 14600 rpm , rev only 500 more rpm to about 15000 rpm but stops there

[RpR]

Exactly where peak power is is up to the tuner that tunes the cylinder. And a cylinder tuned to more rpm always yields more hp.
Kreidler's old record 50cc engine did around 19000rpm max and had 18,5hp. And that was in in the 60's if I remember right.

[TROTIL]

Yes,and SUZUKI made 50 ccm bike in 70-s and it had V3 engine with 14 gearratios,rotodiscs and about 20 hp,and could rev 22000 rpm

[RpR]

Originally posted by TROTIL
Yes,and SUZUKI made 50 ccm bike in 70-s and it had V3 engine with 14 gearratios,rotodiscs and about 20 hp,and could rev 22000 rpm

Yup, but they didn't go 220km/h+ ;-)

[EnergyDK]

Originally posted by RpR
Yup, but they didn't go 220km/h+ ;-)

Nope, but they could steer...P

[ip2]

suzuki only raced the twin 50cc with 21 gears (and not triple ) but Honda actually built a triple 50cc 4 stroke to beat suzuki but it was banned that year .. i dont think none of them had near 20hp but they could do around 180 to 190 kmh depending on condition

1978 Kreidler made 20hp from only one 50cc cylinder and 6 gears , speeds of 123mph or 200kmh mentioned

back in late 60s or early 70s they went 175kmh with only 13 HP , on a single cylinder aircooled 50cc

back in 60s they had a fairing called dust bin which was more aerodynamic than todays stuff (fully covered the wheels and rider legs) later it was banned so speeds droped to 165kmh (over 100mph !)still amazing with only 13 or 14hp and not even water cooling

as you see speed didnt come from power ,they had bicycle size 2inch tires , try that and it adds 20kmh to any bike !

[corney]

Yeah but how hard are they to get through a corner with tyres that thin on it.

[ip2]

michellene had 2 inch slicks specialy designed for 50cc GP bikes , they were in production till 1985 , i had a set back for my moped and i could touch the footpegs on the ground , i remember they were incredibly light and handled so good compare to AVON tires i had before , they wear too fast on the rear so i would not use rear brake

[corney]

Course you had it on the pegs the tyres would not have enough grip to hold it at an angle lol

[ip2]

now thats OT , but definitly bike not resting on pegs ! if peg is solid and hit it bring you down , thats one reason sport bikes use folding footpeg and let it move up just in case , you can tell they grind because of grinding marks

[TROTIL]

Suzuki built V3 engine but they didnt race with it.And it could rev up to 22 000 revs.

[ip2]

NSU built V8 50cc for speed records back in 60s but thats no big deal cause any 10 year old kid can bolt on 10 of 5cc model engine and make 10 cylinder 50cc making over 20hp reving 30000 rpm because parts so small and light can rev to such rpm safely

formula one cars seen rev to 20000 rpm , now thats huge 300 cylinders in there , not sure how long the stroke is but should be more than 39mm

[LorryDrvier71]

I used to race slot cars and had a Ninco NC-2 motor which could rev to 22,000. I estimate it to have made around 0.002bhp!!!

[JonnyRS50]

here is some pics/info on the 12 speed suzuki, talk about old skool lol