Why is my 2005 Venox running horrible?

[baywatch242000]

Good evening.

I am a new member that came across this forum in search of some help trying to diagnose what is wrong with my Venox bike.

I do not know a lot about mechanics on motorcycles and have run into problems with my bike. I'm so frustrated as I've been trying to get it running for about a week with no real improvement.

It's a 2005 Kymco Venox with just 5800 miles/km.

When I try to get it going, the only time it will run is if I have the choke fully out. And even then, it's rough! As soon as I push the choke in, even the slightest, it bogs out until it dies. Even when warmed up, it refuses to start unless the choke is fully open, but because it chugs out and dies as I try to put the choke in, I have been unable to ride it.

Another symptom of troubles is the throttle response. Anytime I attempt to throttle it, it sort of just makes a "poof" sound out of the mufflers and immediately kills - no sputtering, no weird drop idling - just a complete stop of the engine as if I shut it off with the key or kill switch.

About 10% of the time I can get it to throttle correctly by having the choke wide open, and quickly throttling it 15-20 times wide open then back again (literally 1-second throttles that "poof" but don't quite kill the engine since the choke is wide open and I am quickly letting off on the throttle before it kills). Then, eventually after "poofing" the throttle/engine 15-20 times, I am able to throttle the bike - and it sounds great - until I ease up to just an idle which then shuts the engine off again.

So far, I have replaced the spark plugs (they were actually a bit carboned up so I was sure it would have fixed my problems but it didn't seem to have any effect) and drained/replaced the gasoline with fresh premium gas with jet cleaner added. None of this made any improvement - it still only idles with choke wide open - and a horrific rough sounding idle and the throttle is still very unresponsive.

Is there anyone knowledgeable about motorcycle engines that can suggest other things to try? I am so disappointed with how this has gone so far...I just got my endorsement two weeks ago and have been dying to get my bike out but have been dealing with this the entire time.

I have an appointment to take it into a dealership in a week - they are really backlogged - and thought I would just ask to see if anyone that works on their own bikes could offer advice.

Also, because this is the first bike I've bought, I don't know if it's better to seek out repair at a dealership, or if I should really seek out another repair shop? Are motorcycle repair shops like car repair shops where the dealers are always more expensive? If so, can anyone recommend the best way to find a repair person for my bike if I can't figure it out?

It's such a low mileaged bike I can't understand why I am having so much trouble with it.

A few questions - may sound silly to others but I have to ask - does my bike have 2 or 4 spark plugs? I only located two. Would an air filter really be bad after only 6000K miles and being stored inside a garage?

[Vivo]

Before fixing, you really need someone to diagnose your bike... you have two carburetors, right? are they synchronized?

[max oradea]

Hi buddy sorry to hear about your problem, we will try to help you get to the bottom of it and get you on the road ASAP.
A few things we will need you to check.
1. how long has the air filter been in the bike regardless of km used.
2. how many turns in is on your idle throttle stopper setting screw.
3. need a fine pic of your plugs that you took out on the firing side with notice of which is the front and rear.
4. when the engine does run are both cylinders running,to check this feel if the temperature are same on both cylinder and are exhaust pulses equal on both pipes. if you can not get it to run for more then 3 min it is hard to feel the temp difference.
so the trick is run the engine and feel for exhaust pulse difference, then the next trick is check by touch "be careful", touch the proximal segment(just out of the exhaust manifold) of the exhaust pipe of the engine that has a weaker exhaust pulse, if it is cool to touch after just a few min of run then it conferms the diagnosis, that one of your cylinders is not firing.
From what you said about your problems, i would start with the idle stopper screw, and cylinder balancing.
If the bike has been sitting for a while then the main problem can be a blocked idle jet.
a blocked idle jet can cause this symptom of having to use full choke on start and even releasing the choke slightly will cause the engine to stall.
But there is a limbo here!!
1st lets say one cylinder is not firing at idle because of a blocked idle jet, this will require choke to run. on the other hand the cylinder that is operating normal is getting too much fuel... in time it will foul the plugs on normal cylinder, causing miss fire and eventual stall.

[max oradea]

Oh an important notice! exhaust pipes are hot so be careful when doing the touch test.
if your idle jet is blocked, carb. cleaner in the gas will not help a great deal. you will really need to take the idle jets out and blow with compress air and targeted cab. cleaner flush of the jet.
your symptoms at the moment can be fixed easily if one knows what they are doing.
the only thing that will be a little bit $$ is if one of your ignition coil is not working... but on a young bike i would not think so. will need a fine photo of the firing end of your spark plugs to see, or if you know how to do a spark test then it will give a direct answer.
Spark test, require two person, one at the ignition switch and the other holding the spark plug installed onto the spark plug cap(not cylinder head) and holding the ground electrode of the spark plug against the engine casing. the trigger man makes a few rotations with the ignition and the guy holding the spark plug looks for sparks on the spark plug. "be careful" not too many turns and make sure nothing can get sucked into the open cylinder head where the spark plugs was, better put a spare spark plug in that hole just in case, and one last thing you might get shocked so dont hold the spark plug with your hand, use an insulated tool.

[max oradea]

Oh and dont WOT on your engine 15/20 times buddy, 5800km is still pretty fresh, might break something thats not ready for that yet, and if its one cylinder not firing... its a lot of stress on the crank shaft and crank shaft bearings.

[max oradea]

sorry about the bad pic but just giving an idea of how the plug should look like. brown and grey coating on the crown.