GY6 125cc fuel consumption jumped By dusoo (Read 3,387 times)

[dusoo]

Hi Guys,
I've got Torino Galetta 125cc (chinese scooter GY6 with 8000km). It had a problem with starting, it always took around 10sec to start the engine (was killing the battery). I've changed the spark plug, cable, and carburator. This has fixed the problem. After a while (few hundred km), I lost screws to the exhaust pipe + the gasket, so it got loose and extremely noisy with nice popping sound . I bought new screws and gasket, and it was +- fine again. Later (+100km) I started to experience a bumpy ride, let's say if riding around 30km/h (or more/less) I'm getting some inside bumps - it's kind of the scooter slows down for a falf sec, maybe it does not slow down, but its definitely not a smooth ride and maybe related, maybe not, the fuel consumption jumped from around 4l/100km to 6.5l/100km. I've checked the gaskets in the head (was bad, replaced), in the intake manifold (it was ok). Then there is the air filter assy - the filter's arm had a tiny hole in the place where's connected to it's body - i've put some gasket sealant around it, so it should be fine. The filter which is inside is kind of old and dirty (not replaced as I dont have it). Last thing - front wheel - it's turning fine, so it's not adding extra friction.
Could you please suggest what might be wrong?
The bumpy ride - I'm just guessing it might be the air filter - it's not super clean so not getting nice air inside the carby? Or there might be some tiny air leak (where the carby is connected on both ends with hose clamps - I guess not as I always screw them properly). Or the carby's air/fuel mixture screw is not adjusted properly? It's somewhere around factory setup - 2 full turns.
The higher fuel consumption - maybe everything's related - so fixing one thing might fix another
Thanks a lot (Please note, I'm not mechanic and bringing it to mechanic would get it probably fixed - for the prices a of a 2nd hand scooter...).

[crwford]

If you say air filter is kind of dirty then if it's washable then clean it with mild soap then rinse and air dry also make sure you choke is opening or in-richer is opening. Is carb tighten so no vacuum leaks are you running 91 or higher octane fuel? Did you take air fuel screw turn it in a 1/2 of turn to see if it runs if so try that. How is the plug? coil and wire?

[dusoo]

Hi,
Apologies about the late reply.
- In the meantime I have screwed the "air fuel screw" in a bit and this almost fully fixed the bumpy ride.
- I've also cleaned the air filter.
- Im filling the tank with 91.
- After weeks of riding the fuel consumption got down to ~5.3l/100km, which I was happy with, better than 6.5l/100km
- Im riding the scooter on daily basis. (I was riding it, until...)

Anyway, new problem started. Few days back, I was not able to start the engine in the morning, took me around 15 sec to start it. In the evening I had the same problem, but again it started after 15sec. I knew I was running low on fuel on the way back from work. The scooter died just around 200m from home, I'm guessing it died due to being low on fuel. I pushed the scooter back to my garage; filled up the tank the next morning and unfortunately I was not able to start the engine since.
- 
- I have checked and cleaned the carby.
- I have removed the air filter (just filter, not the assy ) so the air is not blocked to flow into the carby (e.g. due to dirty filter)
- I have moved out the spark plug to see if I do have a spark when started. All good. The spark plug was bit black (probably the carby was too rich on fuel). But I could clearly see the spark when I've started the engine.
- Battery is fully charged.
- The engine turns over, but does not start even when holding it for more than 15 sec (I have already killed battery once by trying this).
- There is fuel in the fuel filter, so the fuel must be running into the carby as well. I have not yet tested this theory by removing the fuel pipe from the carby and starting the engine. The fuel should be pumped out of the pipe if everything is fine. I'll test this at one point.
- The carby is just maybe 6 months old, so it cant be carby related.
- I'm getting a spark and I'm getting gas to the carburator and the engine is turning over. I read one article where they had a problem with the automatic choke which failed. I dont have (yet a voltmeter to measure the resistance to rule this part out.
- I will check the valve "lash" - the gap between the valve and tappet. Found one article where the gap was too big and the scooter did not start because of that.
- Another test I found was about checking cylinder compression, but I obviously don't have compression tester (yet?).
- Is this an engine problem (not fixable) and the chinese scooter is finally dead?

Please advise what you would check. Thanks a lot.

[trashtruck12172]

removing the air filter may be allowing too much air in. try to cover a portion of the intake and it may be time to clean or replace the plug.

[Alleyoop]

Saw your video and it DID NOT FIRE ONCE, so do that again and take the SPARK PLUG OUT.
1. Is the SPARK PLUG WET OR DRY?
2. Now stick your finger in the spark plug hole and hold it nice and snuge, HOLD THE THROTTLE wide open and crank it over.
A. Did you feel a little pressure on the finger?
B. Did it lift your finger off the hole?
Alleyoop

[dusoo]

Hi Alleyoop,
1. the spark plug is dry I believe ( it just does not seem to be to wet, its bit black though, but is less than 5m. old)
2b) it did not lift my finger off the hole but the pressure was there, was not light.

another test:
a) I have removed the fuel hose from the carby; cranked the engine and the fuel was coming out, which is good.
b) I have put the hose back and then I tried to unplug the vacuum hose from the T splitter and cranked the engine. I expected to notice some suction but I kind of did not notice anything. Maybe the suction is not really noticeable, and since the test per point above a) was working, I'm guessing the suction is there and the petcock is also functional? 
c) Funny thing happened - I've repeated the above a) test three times. During the second try the engine started?! No fuel running into the carb and the engine started, that's weird isnt it. I'm guessing some fuel excess was left in the carby due to which the engine started. I left it running for just 2 seconds because the fuel was pumping out through the hose... I've connected the fuel hose back to carby to try to start it normally and nothing, it did not fire even after 10 sec of holding it.
What it does it all mean?

Thanks

[dusoo]

Hi trashtruck12172. I will try with a new spark plug, I should have it tomorrow or day after.

[trashtruck12172]

it sounds like compression may not all be there. check valve adjustment. I think it should be the same as a 150cc, alley should know. I don't know if you'll be able to tell with your finger but try this; remove the spark plug and check compression. put 1/2 tea spoon motor oil in the hole and recheck. if compression increases, the rings may need attention. your local auto parts store may have a loan a tool program where you can get hold of a compression tester.

[Alleyoop]

If it did not lift the finger off the hole Adjust Your valves both to .004 inchs. It appears the valves are to tight and are leaking and that is why not much suction is created.
But at least we know it will run since it started once. The problem I see is just tight valves and that will cause lack of suction and lack of gas as well, that is why the plug was dry.

Motors Tuned pretty good will start in 1 or 2 SHORT hits on the start button. If you have to crank and crank then something needs attention. And it will get worse if not adjusted and or fixed.
Alleyoop

[dusoo]

Hi Guys,

Just would like to let you know that the scooter is working from today I've replaced quite a few parts so I'm not sure which modification actually fixed it. I'm guessing valves adjustment, or maybe a combination of others.

Thanks for tips.

- I've replaced the intake manifold and the air filter
- I've replaced the carby (I had a spare one)
- I've adjusted the valves to 0.04 inch (they were really tight, rnd 0.002 inch)
- I've replaced the cylinder head gasket

[freddieb3]

My apologies for jumping-in, I am not used to this kind of format.

I bought an "uncovered" Auto Moto at the end of last season and was only able to ride it a couple of times... but I loved it!

My problem is I can not get it started. It may be as simple as a fouled spark plug but I cannot find a shop/maintenance manual and have not been able to figure out how to remove the seat to get at the engine. I'm used to working on large motorcycles and I don't want to risk breaking a plastic part that I may have porblems replacing. It's been pretty cold in Chicago and I haven't been able to spend much time in my unheated garage. This is about the first weekend that will be warm enough to spend some time to attempt to solve the issue.

My question is this: Are there any on-line videos or possibly a source for a shop/maintenance manual?

Any help would be greatly appreciated.

[e-mail]