50 CC chinese engine tuning

pdegroote · 05-12-2024, 08:41 AM

Hi,

I am the owner of a MASH fifty moped. It is a fun bike, very nimble, but alas underpowered. As I have the license to ride all motorbikes (permit A in Belgium) I would like to figure out if and how the power can be increased and how the limiter can be removed. I am sure that something must be feasible with the ECU (Delphi mt05.2). Possibly some other adjustments may at least optimize the engine. As I remember Honda 50CC four stroke engines develop up to 5HP, whilst this one i listed as 2.8 HP.

The bike is a QM50-2X and the engine is model is K157FMI according tp the manual from the moped.

ProDigit · 05-12-2024, 09:35 AM

I highly doubt Chinese clone engines can reach even 3 actual HP.
They're always blowing numbers out of proportion.

I once had a 50cc scoot which was rated at 3.8hp.turns out it was a big bore 63cc, with an ultra high compression of almost 10:1 for an air-cooled engine.
Many people blew pistons, but the only way to run that high compression, was to run premium high octane gasoline.

Even this 63cc big bore kit, with tuned CVT, and high compression, was just good enough to keep up with traffic until 20-25mph. It was able to hit 50mph easily (that's about 80kmh), but it still was dog slow in acceleration past that.

What you really need is a Chinese 125cc in Europe, or a more modern equivalent 100cc engine of Japanese or Italian design (water-cooled, higher compression, with fuel injection).

In USA even a Chinese 150cc Air cooled can barely keep up with traffic. Over here you'd ideally have an air cooled 250cc or a water cooled 150cc with fuel injection.

pdegroote · 05-12-2024, 10:32 AM

Not really the answer I was looking for

. But you're answer is appreciated anyway.

This being said I just quickly measured teh compression and it it seems way to low..
It reads 6Kg/cm², that is 86PSI for the die-hards. I guess valve and piston ring inspection as coming next...

Bruces · 05-12-2024, 10:46 AM

There are honestly not many moped users on this site ,there are other sites like moped army (if it’s still around ) that specialize in mopeds .
I did see a big bore is available for your engine ,but most seem to be starting with a 125cc base and ending up about 150cc ,so not sure your 50cc would work with any of that as your cases might not be able to accept the bigger cylinder .
Good luck !

Thumper · 05-12-2024, 12:28 PM

It's not a moped, per se. No pedals. Technically I think it is a scooter. LOTS of scooter drivers here.

Looked into it. I can't find a replacement engine, but BDX has a 100cc kit. It is for a GY-6 engine. I do not know what is inside that Mash scooter. Google this, or possibly the link below it might work.

100cc Big Bore Kit - 50mm Cylinder GY6 Scooter Engine

https://bdxperformance.com/products/...scooter-engine

dirtbkr188 · 05-12-2024, 02:33 PM

Does your MASH 50 look like the one in the pic below?

Thumper · 05-12-2024, 03:34 PM

A moped is a different thing in Europe I guess. Mo(no)ped(als)

I saw these motorcycles (dirtbkr188's post) in the 50cc class, but I assumed the scooters were more like a moped than the motorcycle. Those scooters have integrated motor/tranny/rear axle. Nightmare for Chinese replacement parts if you have no idea about fitment

NOW, with this motorcycle ("moped"), there ARE options! Full frame with LOTS of room to work and an engine isolated from the rear axle.

pdegroote We need to know which 50cc bike you purchased. Is it a scooter or the 50cc motorcycle. BTW- a moped has foot pedals for operation without engine. Mopeds are bicycles with an engine.

pdegroote · 05-13-2024, 12:24 AM

Quote:

Originally Posted by Thumper

A moped is a different thing in Europe I guess. Mo(no)ped(als)

I saw these motorcycles (dirtbkr188's post) in the 50cc class, but I assumed the scooters were more like a moped than the motorcycle. Those scooters have integrated motor/tranny/rear axle. Nightmare for Chinese replacement parts if you have no idea about fitment

NOW, with this motorcycle ("moped"), there ARE options! Full frame with LOTS of room to work and an engine isolated from the rear axle.

pdegroote We need to know which 50cc bike you purchased. Is it a scooter or the 50cc motorcycle. BTW- a moped has foot pedals for operation without engine. Mopeds are bicycles with an engine.

This motorbike is a 49,5 CC motorbike, in Belgium (pedals or not) this is a moped. It is restricted to 45KM/h. If unrestricted it becomes a motorbike (legally speaking). It is definitely NOT a scooter.

pdegroote · 05-13-2024, 12:20 AM

Quote:

Originally Posted by dirtbkr188

Does your MASH 50 look like the one in the pic below?

Yes that's the one. About the engine type,although the manual lists it as a K157FMI the designation on the engine says: 139FMB.

pdegroote · 05-13-2024, 12:37 AM

Quote:

Originally Posted by dirtbkr188

Does your MASH 50 look like the one in the pic below?

Yes. That's the one

ProDigit · 05-12-2024, 06:29 PM

I presume he said scooter meaning a CVT, step through design.

Another forum for these type of transportation vehicles is the 'scootdawg forums'. They have plenty of 2 and 4 stroke 25 to 250cc scooters on there, and even some Chinese motorcycles (50-250cc), with CVT or step through gearing.
Once you got manual gears with a clutch it's generally seen in USA as a motorcycle, and won't be on the forum there.

dirtbkr188 · 05-12-2024, 07:39 PM

Apparently, in France they call the bike a moped, as seen on the MASH homepage HERE.
Looking up the engine number posted above, I found the information shown below.

pdegroote · 05-13-2024, 12:39 AM

Quote:

Originally Posted by dirtbkr188

Apparently, in France they call the bike a moped, as seen on the MASH homepage HERE.
Looking up the engine number posted above, I found the information shown below.

Sorry, it looks like the manual is wrong. The engine states: 139FMB. (the engine you showed is a 125cc, my engine is a 50cc)

Thumper · 05-12-2024, 08:00 PM

Quote:

Originally Posted by pdegroote

Hi,

I am the owner of a MASH fifty moped. It is a fun bike, very nimble, but alas underpowered. As I have the license to ride all motorbikes (permit A in Belgium) I would like to figure out if and how the power can be increased and how the limiter can be removed. I am sure that something must be feasible with the ECU (Delphi mt05.2). Possibly some other adjustments may at least optimize the engine. As I remember Honda 50CC four stroke engines develop up to 5HP, whilst this one i listed as 2.8 HP.

The bike is a QM50-2X and the engine is model is K157FMI according tp the manual from the moped.

OP (pdegroote), Find the model number on the engine itself. Is it a K157FMI ?

Your upgrade options depend on the engine.

pdegroote · 05-13-2024, 12:29 AM

Quote:

Originally Posted by Thumper

OP (pdegroote), Find the model number on the engine itself. Is it a K157FMI ?

Your upgrade options depend on the engine.

The manual states: K157FMI, but I checked the engine and it is marked as 139FMB (the vetical type, as that type has a vertical and horizontalversion).

I also checked the compression and it produces 6kg/cm² (some 86 PSI). That may be the reason it feels sluggish.

The engine has an ECU (Delphi mt05.2) and is fuel injected.

05-12-2024, 08:41 AM	#1
pdegroote Join Date: May 2024 Location: Belgium Posts: 15	50 CC chinese engine tuning Hi, I am the owner of a MASH fifty moped. It is a fun bike, very nimble, but alas underpowered. As I have the license to ride all motorbikes (permit A in Belgium) I would like to figure out if and how the power can be increased and how the limiter can be removed. I am sure that something must be feasible with the ECU (Delphi mt05.2). Possibly some other adjustments may at least optimize the engine. As I remember Honda 50CC four stroke engines develop up to 5HP, whilst this one i listed as 2.8 HP. The bike is a QM50-2X and the engine is model is K157FMI according tp the manual from the moped.
	0

05-12-2024, 09:35 AM	#2
ProDigit Join Date: Aug 2013 Location: FL Posts: 366	I highly doubt Chinese clone engines can reach even 3 actual HP. They're always blowing numbers out of proportion. I once had a 50cc scoot which was rated at 3.8hp.turns out it was a big bore 63cc, with an ultra high compression of almost 10:1 for an air-cooled engine. Many people blew pistons, but the only way to run that high compression, was to run premium high octane gasoline. Even this 63cc big bore kit, with tuned CVT, and high compression, was just good enough to keep up with traffic until 20-25mph. It was able to hit 50mph easily (that's about 80kmh), but it still was dog slow in acceleration past that. What you really need is a Chinese 125cc in Europe, or a more modern equivalent 100cc engine of Japanese or Italian design (water-cooled, higher compression, with fuel injection). In USA even a Chinese 150cc Air cooled can barely keep up with traffic. Over here you'd ideally have an air cooled 250cc or a water cooled 150cc with fuel injection. __________________
	0

05-12-2024, 12:28 PM	#5
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,733	It's not a moped, per se. No pedals. Technically I think it is a scooter. LOTS of scooter drivers here. Looked into it. I can't find a replacement engine, but BDX has a 100cc kit. It is for a GY-6 engine. I do not know what is inside that Mash scooter. Google this, or possibly the link below it might work. 100cc Big Bore Kit - 50mm Cylinder GY6 Scooter Engine https://bdxperformance.com/products/...scooter-engine __________________ No matter where you go, there you are
	0

05-12-2024, 03:34 PM	#7
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,733	A moped is a different thing in Europe I guess. Mo(no)ped(als) I saw these motorcycles (dirtbkr188's post) in the 50cc class, but I assumed the scooters were more like a moped than the motorcycle. Those scooters have integrated motor/tranny/rear axle. Nightmare for Chinese replacement parts if you have no idea about fitment NOW, with this motorcycle ("moped"), there ARE options! Full frame with LOTS of room to work and an engine isolated from the rear axle. pdegroote We need to know which 50cc bike you purchased. Is it a scooter or the 50cc motorcycle. BTW- a moped has foot pedals for operation without engine. Mopeds are bicycles with an engine. __________________ No matter where you go, there you are Last edited by Thumper; 05-12-2024 at 04:15 PM.
	0

05-12-2024, 06:29 PM	#11
ProDigit Join Date: Aug 2013 Location: FL Posts: 366	I presume he said scooter meaning a CVT, step through design. Another forum for these type of transportation vehicles is the 'scootdawg forums'. They have plenty of 2 and 4 stroke 25 to 250cc scooters on there, and even some Chinese motorcycles (50-250cc), with CVT or step through gearing. Once you got manual gears with a clutch it's generally seen in USA as a motorcycle, and won't be on the forum there. __________________
	0

05-12-2024, 10:32 AM	#3
pdegroote Join Date: May 2024 Location: Belgium Posts: 15	Not really the answer I was looking for . But you're answer is appreciated anyway. This being said I just quickly measured teh compression and it it seems way to low.. It reads 6Kg/cm², that is 86PSI for the die-hards. I guess valve and piston ring inspection as coming next...
	0

05-12-2024, 10:46 AM	#4
Bruces Join Date: May 2018 Posts: 1,649	There are honestly not many moped users on this site ,there are other sites like moped army (if it’s still around ) that specialize in mopeds . I did see a big bore is available for your engine ,but most seem to be starting with a 125cc base and ending up about 150cc ,so not sure your 50cc would work with any of that as your cases might not be able to accept the bigger cylinder . Good luck !
	1

05-12-2024, 02:33 PM	#6
dirtbkr188 Join Date: Aug 2009 Posts: 572	Does your MASH 50 look like the one in the pic below?
	0

05-12-2024, 07:39 PM	#12
dirtbkr188 Join Date: Aug 2009 Posts: 572	Apparently, in France they call the bike a moped, as seen on the MASH homepage *HERE*. Looking up the engine number posted above, I found the information shown below.
	0