Run out of ideas - Please help

My son recently bought a second-hand Motorini Misano 50cc 4 stroke Injection model Moped.

It’s been running like a dog since he bought it. This is what I’ve currently replaced.

Cylinder, piston and complete cylinder head was getting 40psi, now getting 130+psi

Thought I’d sussed it.

Started running bad again.

Services the whole bike, plug, air + fuel filter, all oils – then replaced drive belt and rollers.

Still run bad.

The bike seems super slow, barely getting 10mph on inclines, and no power when accelerating.

I know it’s going to be slow, but not this slow.

It’s just started losing power when running after few minutes – I also think it runs really hot.

What can I try next?

I believe it’s a fuelling issue, but I don’t want to throw more money at something that won’t fix it, but I’ve already replaced nearly everything.

I’m thinking it could be the Injector or the fuel pump – does that sound possible?

I also need to add, I’m hands-on, but no trained mechanic. I’ve currently watched countless youtube videos and asked advice from friends – but I’m now completely stuck.

Any advice would be greatly appreciated.

Also – no bike shops will touch it because its Chinese and not worth the money, I can totally agree with this. But, my son bought it with very little money spare – so he has no choice in the calibre of mechanic now working on it (ME)

 

Does it still have the standard exhaust fitted?
Is there a check engine light on the dashboard? Should light up for 3 - 5 seconds when switched on, then go off if there are no faults....
Is the o2 sensor in the exhaust?

 

Yes, standard exhaust still fitted
it goes off as described, but will come on after riding for a while sometimes. when restarting the bike it will go off again.
O2 sensor is in the exhaust - I haven't removed that.

why do you point to the exhaust?

 

Looking into the make of this, it's possible it has some attachment to Sym scooters. But don't quote me on that........
Fuelling is controlled by the ecu. It won't have the conventional cdi that a lot of Asian made scooters have because it is fuel injected.
I mention the exhaust because people think that just changing that for a louder sounding one will make it run better. With injected bikes it doesn't; they need to be re-mapped to compenstae for the emissions getting out faster.
If emissions get out faster, then fuel needs to get in faster to balance the running. Hence the re-map.
If the check engine light is coming on whilst riding then that says it has a problem. I have known Lexmoto scooters to run badly because the o2 sensor in the exhaust is failing. Most scooters use the same diagnostic software, CMPO have a diagnostic tool that might cover your bike but it's worth giving them a call to see if it'll work with that make before shelling out any money for it.
I would pull the ecu and do some digging on any numbers/names/lettering you can find on it, more than likely there are many bikes that use the same one.

 

yes you're correct it looks like this;



ah, I see, no exhaust is all standard.

I have been looking at these items on Amazon. I believe they fit my OBD port. How easy is it to translate the info from the reader to determine where/what the issue is? I've never used one.

if it is a simple faulty sensor issue, would the reader determine that?



Thanks for the response

 

The reader will give you the fault code, then you can either google it or if it's got the facility it'll let you press a button or icon and search for you

 

Thought I was getting somewhere, compatibility issues I assume.

so I got this on the reader;



The reader powers up by turning the ignition on, so i thought I'd cracked it.

Any idea what the issue could be? The reader or the adaptor? Photos below to help.







I purchased the one's from Amazon as previously posted.

 

I think I've sorted it! I've been setting the valve clearance at 0.04mm as per a workshop manual I've downloaded. As previously suggested it loses power after a minute or two. I googled the issue again and found someone advising the valve gap could be too small when this issue occurs. I've just googled the valve clearance on these engines and someone suggests 0.004" - I've changed it and it runs instantly better with no power loss after 10 minutes of riding.

taking it for a longer run later today

 

Can't see any images.....

 

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