VHM dyno test Aprilia RS125 with VHM cylinder head

www.vhm.nl/AA3...
Testing this Aprilia RS125 on our dyno test bench, with VHM cylinder head (AA33190) and combustion chamber (AE32008-F).
First starting and warming up the engine, then you can see a few dyno runs, with dyno graph at the end of the video.

[@cagr4249]

Please can you show the curves in the common form, that is: power (or torque) above rpm?

[@yteb08]

VHM dyno test Aprilia RS250 with VHM cylinder head

[@Endrjo]

i dont believe in this results. look like some dyno cheat just to sell the product. in fact full unrestricted rs125 generates around 29-30hp in real.. for 36hp is needed race ignition, perfectly matched expansion chamber, carb etc etc.. not possible for almost stock engine like here.

[@ams668b3]

Why not. It could have a 1-ring piston and rave 2 exhaust valve. The cylinder head is the brake in rotax 122 and 123 engine and nothing to do with the exhaust bc its perfect.

[@de_knaupes]

Was something changed in the carburettor setting or was the cylinder head simply put on it?

[@macariorodriganez1477]

Great Video! the test is with 95 or 98 octans?

[@skogpekka]

36hp~? In other words; completely derestricted, with different exhaust valve & the works. I bet it's fun to ride. =)

[@Tiwey]

no. base power for the extrema series of bikes are 34hp (and that with the 34 carb). This is the MP model at around 32 hp This is really good performance for just a cylinder head

[@Tiwey]

@@krazed0451 yes cylinder head but not the exhaust. the cylinder head of the rotax 122 is composed of 2 parts: - A combustion chamber and a cylinder head ontop. Therefore the cylinderhead is cooled (making it one of the few engines with cooled cylinder heads)

[@Tiwey]

@@krazed0451 What? The current exhaust is original aprilia exhaust system. Its fitted with vhm head and combustion chamber D;

[@13thdukeofwybourne69]

@@krazed0451 Certainly looks like totally stock Aprilia expansion chamber and end can (although unrestricted). edit... reading the OP comments (VHM, the manufacturer of the head) they confirm this is a normal factory exhaust.

[@chaliceabuuu2147]

Is this for the rotax 122 a d where is the link to buy it lol

[@stevenbusk539]

What would be the best compression ratio with the VHM head for 98 unleaded fuel, and also for race fuel if you have a high compression insert?

[@VHMspecialracingproducts]

Our VHM standard insert is with 11.60cc (AE32008-F), with race fuel you can also go with the AE32008-E (11.40cc).

[@lorenzoparro702]

Has it the original exhaust?

[@VHMspecialracingproducts]

Yes the test was done with the original exhaust.

[@Endrjo]

@@VHMspecialracingproducts you received 35-37hp result just with vhm cylinder head? Was the carburettor re-jetted?

[@ams668b3]

​@@EndrjoYes I believe so. I just orderd last week from mmg racing store and the power boost is so fucking amazing + i got the italkit 125 cylinder kit with twin ring piston. Even thought I have phbh 28mm carb its still so powerful 😍😍

[@gabrielerossi8398]

Head volume and squish?

[@VHMspecialracingproducts]

Hi! This is with our AE32008-F insert, with 11.60cc (including volume of the spark plug hole) and a squish of 0.90, you can find all details at: www.vhm.nl/en/catalog/engine-parts/cylinder-parts/vhm-head-inserts/ae32008-f/infoorder/g+c+a+nr+view

[@gabrielerossi8398]

@@VHMspecialracingproducts thank you

[@macariorodriganez1477]

With 28mm or 34?

[@noise3066]

28

[@TheCh4s3]

3hp shy of what a GP125 makes VHM? Your dyno is well overdue calibration or you’re misleading people with fisher numbers.

[@edoardorizzardi2821]

I casi sono due: il banco regala cavalli oppure la moto non è originale

[@bvideos1518]

Ma se nel grafico segna che standard gli ha fatto 35 CV🤣🤣🤣 impossibile sinceramente, se sei fortunato secondo me arrivi a 30-32 all'albero

[@ex3221]

Ha la testa vhm

[@matteoprada5851]

@@bvideos1518 no è possibile, non sono in italia, veniva già venduta stappata all estero, solo da noi hanno iniziato a cagare la minchia con i 15cv

[@bvideos1518]

@@matteoprada5851 ho capito ma in ogni caso la versione Di RS che dovrebbe sviluppare intorno ai 34cv a potenza piena è la prima generazione, che montava il rotax 123, dalla seconda generazione alla quarta non sviluppano neanche 30 credo originali solo ripotenziate e questa secondo loro stock arriva a segnare 35cv

[@matteoprada5851]

@@bvideos1518 no no zi il rotax 122 andava di più del 123, era solo bloccato