Hi all , new owner of a used 2005 Zx50 fever , 2nd day prob

[govango]

Just got a used ZX50 fever last week.    Test drove it around before I bought it , seemed fine.

Had a new piston, new belt, carb clean done.    Has 20km on it.     Noticed Oil tank was low

that I couldnt see any oil coming near the fill line.   They put in a small 1 gallon size syth 2 stroke oil bottle.

Thing was smoking when I drove it home , (which I am told 2 stroke are supposed to do )

I get it home and didnt ride it until today.    I filled tank with high octane and put in a 12 oz bottle of pre mix 2 stroke oil

full synth , and it still doesnt show any oil visibly in the tank.    How much does this thing hold? 

Also started it up and see NO smoke whatsoever .    But I drive it about 3 miles its running great , Im 280 lbs and it was

going 35 to 40 mph fine.   Then it just dies.  no warning just stops .    Like someone hit the kill switch.

I wait a second or 2 and then it fires up fine but now WOT is like half power.

I take it to the shop I got it at and the big concern was no smoke.   So they added oil mix to the gas , in case

the injector wasnt working.

I start it up and it starts up fine ,  I head back home its running great even uphill and then wham again just dies.

I wait a few and start it up and fire up but again runs to where WOT only does like 20mph.

Any ideas?         Also how much oil does this take? I found online manual it doesnt say.

Thanks

[90GTVert]

Welcome to the forum!

It's normal for a two-stroke to smoke. I'd be more concerned if I never saw smoke, because the oil goes through the engine along with air/fuel. That's how it lubricates the engine, but that also means it burns during the combustion process.

I've never bene around a ZX50 to tell you the oil capacity. Most of the ones I've seen hold up to a quart or so. Look for leaks. If you're losing much oil from the reservoir, it should be fairly obvious with a quick inspection. That would be the only possibility if the oil is disappearing and it's not smoking a ton. Even if the pump wasn't working, the oil wouldn't just disappear. I'd say figure the reservoir/plumbing situation out as the first step.

It sounds like the engine is seizing from either lack of lubrication or overheating for another reason. A couple of common causes are lean jetting, air/vacuum leaks and cooling system problems.

[govango]

Thanks for ideas 90GTvert . Question about "seizing" . So basically its the piston expanding in the cyclinder due
to whatever reason , lack of oil lets say. The first time it did it I still was able to coast with it . And then it started back up no problems but yes lack of power. Went to shop , they added oil to gas , drove it home it was running full power again , then it "seized" again was able to coast down hill about 40 ft . Waited minutes , it started up fine and went home
about 1/4 mile again though with low power.
Question , does a seized engine allow for coasting? I would have thought being seized would mean it would die and wheels would not spin, also would a seized piston then allow 2 times to quickly restart? Asking to eliminate whats wrong.
Thanks. I will have to do all the work on this I can't afford the shop. Add to this I have never worked on a engine in my life lol

[wiscootsin]

If you let it sit awhile non-running then start it (or let it sit idling for awhile) can you get a decent WOT run with it? If you ride it consistently at 28mph (or whatever half throttle may be for example) can it hold that for a long time?

maybe it's not getting enough fuel and the scooter dies when the carb empties. If that's the case it could be carb float related or fuel petcock/tank related.

Try out a few situations to see under which ones the scooter dies or which it doesn't.

Is the stock airbox on it and unmodified? sometimes people take a small piece off the airbox of these which increases airflow.

[govango]

Jan 24, 2023 22:50:00 GMT -5 wiscootsin said:

If you let it sit awhile non-running then start it (or let it sit idling for awhile) can you get a decent WOT run with it? If you ride it consistently at 28mph (or whatever half throttle may be for example) can it hold that for a long time?

maybe it's not getting enough fuel and the scooter dies when the carb empties. If that's the case it could be carb float related or fuel petcock/tank related.

Try out a few situations to see under which ones the scooter dies or which it doesn't.

Is the stock airbox on it and unmodified? sometimes people take a small piece off the airbox of these which increases airflow.

You hit it,  it was more fuel related .  First I put in a new filter and tested if gas would come out with the fuel line pre filter,

was fine gas was coming out.  Put filter on and tested line before carb and gas was coming out but what was bothering me

was looking at the filter it just never filled up , the most gas was like a small amount filling up bottom 1/8 of filter.

Questions .    The filter is located by the seat and sits sideways , not vertical , is that normal?

So new filter , checked fuel lines took for a ride and still dies.     Then read about fuel vent blockage and gas tank cap also being issue.

I unscrewed gas tank cap and just set it on it with half turn not full turn.    Now I was able to go full distance with no dieing.

So what does that mean?   Do I need new gas tank cap or is there some line (was seeing vent line?) I need to change?

Also on carburetors,  I want to get a new one just to have.   Whats the diff between 18 dollar amazon carbs and some are 200 dollars?     Can I get buy with a cheap 18 to 25 dollar carb?    thanks again.

[gooddog]

hi I had a 125 kymco agility with same fuel tank problem. I think I cut just a tiny bit of the fuel cap gasket to let some air in and it worked. never had a problem after that with starving the carb. Thats a four stroke engine of course. Only happened on very warm days. But same concept. Sounds like your carb is doing fine with better fuel flow.