gilera gsm


faster and faster
im considering buying a gsm as there is one as a project from my local shop and they want £130 for it

obiously i will have the whole bike striped down rebuilt with a 85 kit and exhaust to suit and the other bits and peices

basicly im looking to know if the engine (i think morini engined) is any good?

i have a debait with my 2 other m8s and they have the new shape 09 derbi senda and a gilera rcr both with 85 kits and the rest done

is the engine any good for tuning or will i be waisting my money?

i want the fastest set up is it possable out of the gsm (03 plate)

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melf #50

Well-Known Member
the Morini engine can be fitted with a Gilardoni 70cc cilinderkit , and a Metrakit exhaust , also a 19mm carburettor , get the sprockets right and it will do about over 100 on the original speedometer.

I did this with 2 gilera gsm's like this and both of them did 115/120 on the speedometer.

the engine is allright ,of you keep it in good shape.

Top racing also have crankshafts for the Morini type engine.

cilinderkit :

exhaust :

carburettorkit :

sprockets :

these links are just to show you the products :)

I hope this was what you where asking for?


faster and faster
speedo spees and real speed are a lot different though
what sorta speeds were u looking at?

is it any competition to the am6 engine say in a rs50?

i just seen one advertised with some minor engine work needed for only£250:O
just a couple of hours drive away:(

i have never heard of the company for the cylinder you listed would it be as powerfull as say the polini 80's kit with a polini race exhaust??

melf #50

Well-Known Member
Polini used to let Gilardoni make their cylinderkits..

That is Gilardoni..

so it is absolutely a famous company ;)

also al lot of stock cylinders are made bij Gilardoni , like the stock one on your gilera , also AM5 and 6 and lots more!

for the Morini GSM this is de best cylinder there is in my opinion , there is also a Conti cilinder , but that's a 50cc , and Metrakit also has a Cilinderkit for GSM , but that's a cast iron cylinder..

for AM6 engines there a lots more cylinderkits avaible , and ones with more poweroutput , but the whole setup has to be right for those cilinders otherwise it's a waste of money..

also there are lots more exhaust pipes , carburattors , crankshafts , clutch parts etc.


faster and faster
would it be possable to make a setup for the gsm that will give to most power output. with that cyilider kit would it be as powerfull as the polini 80's kit

just looked at the Gilardoni kit and it said anywere from 11-13bhp
is there anything on the market that would give more power?
would it be possible to get around 20bhp?
is there a metrakit cyilnder kit thats powerfull?
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melf #50

Well-Known Member
80cc is not always faster then a 70cc , i't's all about the porting of the cylinder..

if the 80cc kit is a cast iron cylinder then do not think to much of it..

for Morini gsm the Gilardoni 70cc kit is the best kit to use ,std from the factory , and for tuning purposes cause of de internal shapes of the ports ,and it's aluminium with 1 pistonring.

there is potential , but only by tuning the cylinder the engine could create 20 bhp , but not with the exhausts that are avaible for the morini gsm , for that you'll have to get another exhaust from another model to fit.

so it is possible but not so easy as a Am6 engine , or Derbi..

The metrakit cylinder for gsm is a cast iron cylinder with 2 pistonrings , and a very low timing , not suitable for high revving..


faster and faster
right i am a little confused over what engine it is as i have been on adreniline pedstop and it says that the gsm >2002 is derbi and mine is a 2003

is that the derbi motor or morini
and is it possible to fit an am6 engine into the gsm
or any 85 motocross engine:p


faster and faster
just did more reserch for the gsm and i think it is the derbi motor that it has

what cylinders will be most suited for power on the derbi motor

thanks for your time


melf #50

Well-Known Member
it is always possible to make an engine fit in there , but that will not go easy and wihout welding and modification.

the most gms's are Morini engine , you can easily see the difference between a Morini en derbi engines , on the Gilera Zulu (gsm cross version) the derbi engine is stock.

I have acctually never seen any gsm with a derbi engine.

but they should excist..

melf #50

Well-Known Member
this is a Morini engine..

the Metrakit SP kit is not the most powerfull cylinder ,if I had a Derbi I would use cylinders like Malossi MHR , of MHR team , Metrakit Prorace , Hebo manston/pata negra etc.
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