BIg Problem with my Zong.

[SpudRider]

If you don't have water in your fuel, or varnish in your carburetor's jets, I suspect a failing CDI unit. Based upon my experience with this motorcycle, I doubt the gas tank has venting problems, but it's possible.

I strongly suggest you get a spare CDI unit as quickly as possible, even if this problem is determined to be fuel related. All the Chinese CDI units are prone to failure, and your Zong is not exempt from this generality. A spare CDI unit greatly facilitates troubleshooting problems such as this. In addition, when, not if, your CDI unit fails, you can install the spare CDI unit and keep riding. Otherwise, you will be unable to ride the bike until the very slow boat arrives from China.

[Weldangrind]

I hope we are not giving you too many answers, but I think it's a crankcase ventilation problem. There is a large black hose underneath the carburetor, and it probably routes behind the engine and points at the ground. If it is clogged, pressure in the crankcase will push oil out somewhere else, just as you observed. Make sure the hose is clear, and make sure it is not kinked.

[SgtRope]

Ok so today i did about 100km(62miles) keeping the average speed to about 100kph/60mph , not full throttle like yesterday which caused the seizing/overheating.

I also checked the spark plug ( picture belowe). and where simular to one of these which might suggest to lean.

Also there is no vent in my Fuel tank.
And my chain looks a bit on the loose side? and as you can see there is some oil on the rear Tyre and rim.

Then the last picture shows where the oil is coming out . also its only coming out of the left side not the right.

[katoranger]

Does it hop like a kangaroo?

[SgtRope]

haha no!!

[Weldangrind]

Your fuel cap has a vent built in.

[Wild_Alaskan]

too lean can indicate lack of fuel in the carb, such as the float height being too low from lack of fuel flow, Or being to lean because of jetting causes excessive heat which can lead to heat seizures, I would still bank on a fuel flow problem. get a new cdi as spud suggested, they are a cheap way to narrow problems down on these bikes

[Wild_Alaskan]

also unless you are going for all out gas mileage, shoot for a tan-brown color on the spark plug, that typically where you make the most power as well.

[SpudRider]

Based upon my experience I doubt either the crankcase vent or the fuel tank vent are causing problems. However, both are easy to check, and can be easily verified, or eliminated as problems.

As WA suggested, the next time you have the problem, open the fuel cap and see if you hear a sucking sound, or notice a vacuum. Then note if the problem disappears.

The crankcase vents into the air box, and rarely, if ever gets clogged. However, you can easily examine the crankcase vent tube by removing it from the crankcase and the air box, and examining it for obstructions.

I also doubt the engine as seized. The Zong's carburetor is jetted properly for sea level, and is invariably rich at higher altitudes. Also, the engine is manufactured to very high standards. I have never heard of a Zong or TW200 engine seizing from a too lean fuel mixture.

I strongly suggest you do yourself a big favor, and get a spare CDI unit as quickly as possible. CDI failures are intermittent for a while before the CDI unit fails completely. You really shouldn't be riding now without a spare CDI unit, as you are very likely to get stranded, usually in a bad place at a bad time. Also, you need a spare CDI unit to troubleshoot possible electrical problems such as this.

As I stated earlier, I would also check to see if the carburetor and jets are gummy with varnish. However, I strongly suspect the CDI unit has failed. You are experiencing classic symptoms pointing to a faulty CDI unit.

[SpudRider]

I suspect your drive chain might be oiled too much. However, you do need to verify the location of any possible oil leak from the engine. Spray the suspected areas of the engine with brake cleaner. Then wash the bike to remove the grime. Once the engine is clean, keep examining the suspected areas to see if oil is indeed leaking from the engine.

Also, I suggest you clean the rear wheel and the drive chain. You can use WD40, diesel fuel, et cetera. Then apply chain wax, 90W gear oil, or any other clear lubricant. If you don't see oil coming from the engine, and the oil disappears from the rear wheel, you can verify whether the drive chain was oiled too much.

[edtardo]

I don't know if this will help, but I was having a similar problem. I checked everything I could think of, turned out that the connector on the wires coming out of the engine had melted and was shorting out.

[Weldangrind]

Ed, that's awesome! I hadn't even thought of electrical trouble.

[SpudRider]

Indeed, that's a good suggestion, Ed. The wires from the stator and pickup coil exit the left crankcase cover near the clutch lever arm on the left side of the engine. One should make sure they are not pinched, or damaged in any way.

I doubt either the stator or pickup coil are damaged on a bike with so few miles on the odometer. I strongly suspect either a gummy carburetor, or a bad CDI unit. In either event, one really needs a spare CDI unit for his Zong, or any Chinese motorcycle for that matter.

[SgtRope]

Hi Guys

Ok so my previous post i talked about my bike giving little jerks and pulls when riding for a while . so this moring i completely stripped down my bike to look at everything.

few things i noticed .

1.crankcase cover botls where loose so might explane the oil leak.
2. completely removed my fuel tank , drained it to look for rust etc. (clean)
3. the carb hose that ran from the carb to my air filter was completely loose which could explain a few of my problemes.

4. Also adjusted my PCM screw on my carb to 3.1/2 from 3. 3/4.
5. the oil filter is stainless steel so it can be rinsed if you want to clean it.

i have check everthing , no loose wires , bent or kinked hoses.

so if my bike still cuts out or give these little jerks i will have to replace the CDI unit.

thks for all the help

[SpudRider]

You're making good progress.