Done everything and still not starting/running! By sooonmitch (Read 1,889 times)

[sooonmitch]

Ok so.... Lets get straight to business.

I recently bought a Roketa Bahama 50cc 2008 scooter. It ran-ish. It had bearly any power and couple bearly get a top speed of 20 mph downhill. Terrible, so I decided to work on it. I was able to adjust the valves, and even opened up the carburetor and cleaned it out. It would bearly start up but when it did it helped a 3000 RPM and I could drive it mostly. I drove it around, hoping that it iron the starting issue out and it worked for a bit untill I would get a higher speed and it would start bogging down randomly and even started back firing. Now it will not start up a day after.

It still turns over, it "gets hot" indicating combustion. It does not start though. It never started easily since I got it and now I have done all these things and cant think of anything else to do.

• Messed with F/A ratio
• Messed with Idle
  
• Messed with valves
  
• Messed with the cam shaft and even tuned it to the "T" line
  
• It gets gas
  
• It injects the gas with the electric injector.
  
• Starter works fine / battery is charged and ready to go. 
  
  
  I am out of ideas at this point. Please any help or advice would be great! This is my very first actual moped other than dirt bikes and four wheelers. I really want to ride it and have fun but its raining on my parade :/ 
  
  
  
  
  

[Alleyoop]

Well if it is backfiring that is caused by only TWO THINGS.
1. it is out of time
2. You have a very bad AIR LEAK causing it to run very lean.

So best thing to do right now is align the CAM as if your going to adjust the valves TAKE A PICTURE then take a picture of the FLYWHEEL so I can see if it is timed right.

Also take a picture of the top of the motor so I can see the CARB, INTAKE MANIFOLD and AIR FILTER.
Also check the FLANGE that is where the pipe bolts up to the motor, many times nut or one stud break or come off and a very bad air leak happens there causing backfires.

[sooonmitch]

Here are the pictures: goo.gl/photos/RK7CxMJPWYP4DaH36

(My google photos)

[Alleyoop]

That all looks good on the timing. You do have an AIR FILTER on it right? Also check the FLANGE and make sure it is not missing a nut or stud.

You have one Vacuum hose bent over and zip tied so it does not loose vacuum, the other hose I would guess goes to the PETCOCK? Also minor thing but Your FUEL FILTER is bacwards, the big end always goes toward the carb, you want the gas to come in from the outside of the filter. The other way can can restrict a good glow of fuel to the carb. Also make sure the fuel hose does not have any ups and downs sense it is a gravity system it has to flow downwards to the carb.

Next thing would be to test your compression take the plug out stick your finger in the hole nice and snug hold the throttle wide open and crank it. If it has descent compression it will lift your finger off if you feel just some pressure then either the valves are leaking or rings.
Alleyoop

[sooonmitch]

I have tested the spark plug thing and it did lift my finger unless I really tried to force myself to hold on. I do have a concern tho. The gas vent that is on the head block that you take off to access the Cam/shaft stuff really puts out a bunch of puffs when turning over. Could this be an issue?

Also yes one is to prevent lose, and the other goes to the gas thing which I assume the is the PEACOCK. So far that I can tell is that it does not have a leak their. I tighted and made sure their is no cracks and made sure the gaskets fit.

Another thing is their is no bolts/nuts missing. Seems secure also.

[Alleyoop]

Do you have a hose attached to it? The hose should not be bent or kinked it has to VENT otherwise it will not vent.

How about the AIR FILTER is there one on the carb.

[sooonmitch]

No I took it off as I was working/trying to get it to work. Plus it was in the way. When it gets going again I will add it back.

Also the air filter did have it linked straight to it but I took it off again just to make sure its getting air and everything else.

[Alleyoop]

Well without the air filter you will have a harder time getting it to run, that will cause a VERY LEAN condition and adjusting the carb with it off is just a waste of time. You need to have the AIR FILTER on when adjusting the carb.

[sooonmitch]

Alright I will do, should I attach the hose back? And is this my issue of it not running or is this a side issue?

-Side note: What does that little hose do from the head block? Why so much air pumping out of it and whats the point?

[Alleyoop]

That is PCV VALVE to relieve the pressure in the crankcase the hose is just so it does not squirt oil all over the place in front. With a hose on it you can zip tie it higher than the valve cover and if it squiarts oil out it will not go all over you motor or tire etc..

Well it is late around here and time for me to knock of some zzzzzzzzzzzzzzzzz's but just keep this in mind IF IT BACKFIRES it is VERY LEAN and usually when they backfire it is sucking in air from somewhere. The fuel delivery system and air is a CLOSED SYSTEM and any EXTRA AIR from someplace will cause A LEAN CONDITION.

I have also seen bad CDI's that will cause the timing to go way off so that is also a possiblity if no leaks and the motor is getting plenty of gas.

I will check for any updates tomorrow.
Alleyoop

[sooonmitch]

I really would rather not tear the engine apart. Do I have to? Does the situation look like that? Or is their other ways/things?

[Alleyoop]

Please explain when it starts to backfire on you.
1. Does it backfire when your it is picking up speed?
2. Does it backfire when you let off the throttle?
3. Does it backfire when you just twist the throttle?
Alleyoop

[sooonmitch]

The main issue at this moment is that the scooter is not starting anymore. It does turn over and does get really warm but it will not startup. I am going to get a new CDI today but I have been thinking that it could be the rings around the piston since it has been sitting all winter. So I cant tell you no more if it is backfiring since I cant get it running at the moment.

[Alleyoop]

It could be that it is not getting gas,after sitting for months without starting the carbs pilot jet and passage is all varnished up. Also make sure it has oil so check the oil level and if it smells from gas change it. So crank it trying to start it a few cranks and then take the plug out and see if it is WET OR DRY. Now while you have the plug out stick it back into the boot and hold it on hold on the valve cover and crank it and see if the plug is firing.

Well if it was the rings it would not have lifted your finger off the plug hole when checking the compression.
So since you checked for descent compression and said it lifted the finger off then that is out of the picture. So it has to be one of TWO things fuel delivery problem or no spark.

I can only go by what you tell me.
Alleyoop

[sooonmitch]

It dident lift my finger when I actually held with some force. But it does have a spark and it does get gas.