how much to fix a motorcycle with a flooded engine?

Take out the spark plug, fill it with diesel oil, then let it sit for a day or so.  With the plug still out, crank the engine so that it spits out any remaining diesel.  Change the oil as it may have water in it and it will by now be mixed with diesel.  As the Nouvo has only one cylinder there is no distributor but check that all wiring is dry.  Put the plug back in and try.  If it still won't start, it may need to be torn apart.  I expect that with the cost of labor, you may be surprised at how inexpensive that can be in the small neighborhood shops.  As you seem to live in an apartment, this remedy could get a little messy so, again with the cost of labor, going to the shop may be the first best option.  If you can have a Vietnamese friend push it in for you, you may (will) get a better price.

G'day Villa,
You'd be surprised how far a few dollars  goes here in bike repairs.  In your case , very few parts, if any required, just a bit of cheap labour.   

I'd be taking the opportunity to get the thing checked over totally if they've got to pull the motor apart.  A new set of rings etc ...

I bought a 2nd hand Honda wave  , took it a mechanic I was referred to and put news tyres & tubes, new chain & sprocket, new brake pads front & back, new plug, mirrors, and a general service & tune , for $52.   Not bad.

Back home in Australia , the tyres alone would have been @$500.....and the labour ????
I wouldn't have got much change from $1000. 

Definitely worth getting it fixed mate.

From your post it's not clear what's really wrong with it.
My first action would be to bring it to the first mechanic along the street and let them look at it.
For them to at least see what's the matter with it will cost less than a few dollars.

You say it "can't start", what does that mean?  Does it even try to start? or does it sit there without a sign of life.  The latter is probably better because then it's an electrical issue.  Is your battery flat?

Anyway, just bring it to anyone and then you will know more than you know now.

dear all,

thank you for sharing your opinions and feedback.

@wxx3 - when i say it can't start it means that when i press the electric start, nothing happens. bike is completely dead. no sound, no nothing.

anyhow, will bring the bike to a neighbourhood shop.

once again, thanks to all for your input.

hello all, so I pushed the nouvo to a bike shop on huynh tan phat. as i'm really unfamiliar with bike parts and what not, i'm unable to tell you what was done other than a change of battery and lots of general tinkering about.

total bill - 560k + 20k to scrub the months of dust and shiet that had accumulated on the bike.

Thanks everyone once again for their input.

Glad you got it working. Yes, totally dead like that is usually the battery. 
Next time get it looked at right away. If battery if flat, it can sometimes be recharged.

I'm guessing the water immersion allowed the battery to discharge over some time. 

Did he also look at the oil? (pull dip stick and look at color to make sure there is no water in it).
Usually they do check for you.

As others may read these replies for future problems, being a mechanic, I will advise what the first steps should be in the event of a flood water related problem. As soon as possible the spark plug should be removed, and the air cleaner if the flooding was up to that level. The engine should be cranked over, by either starter, electric or kick, or if manual by pushing the bike, or in the event of no other option by hand on the flywheel. repeat for about 1 minute. Check the oil level, if the oil is grey or has water in it, remove all oil as soon as possible. Replace with new oil. replace spark plug and try to start. If this does not work or you are not comfortable with these procedures then head straight to a mechanic. As delays will cause rust, often the rust on the crank ignition trigger/ flywheel on some models will prevent starting, a bit of emery/ sand paper rubbed on the flywheel will have it sparking again. Also a liberal does of water dispersant like WD40 etc will help. main thing is don't leave it a few days, as getting it going will help dry it out. ( do not try to start before removing the spark plug and cranking to ensure the water is out) or else you could bend rod or valves. Water does not compress.
Safe Travels.

The Freeranger wrote:

As others may read these replies for future problems, being a mechanic, I will advise what the first steps should be in the event of a flood water related problem. As soon as possible the spark plug should be removed, and the air cleaner if the flooding was up to that level. The engine should be cranked over, by either starter, electric or kick, or if manual by pushing the bike, or in the event of no other option by hand on the flywheel. repeat for about 1 minute. Check the oil level, if the oil is grey or has water in it, remove all oil as soon as possible. Replace with new oil. replace spark plug and try to start. If this does not work or you are not comfortable with these procedures then head straight to a mechanic. As delays will cause rust, often the rust on the crank ignition trigger/ flywheel on some models will prevent starting, a bit of emery/ sand paper rubbed on the flywheel will have it sparking again. Also a liberal does of water dispersant like WD40 etc will help. main thing is don't leave it a few days, as getting it going will help dry it out. ( do not try to start before removing the spark plug and cranking to ensure the water is out) or else you could bend rod or valves. Water does not compress.
Safe Travels.

Good lad! Thank you very much, Sir.

@The Freeranger

Hello

I have a kengo 400 and the top head cylinder of the engine is leaking oil . Also sometimes the engine stops running when pressing the clutch.

Been trying with few mechanics but without success.

Can you repair it?

Bo Dao Nha

@The Freeranger
Hello
I have a kengo 400 and the top head cylinder of the engine is leaking oil . Also sometimes the engine stops running when pressing the clutch.
Been trying with few mechanics but without success.
Can you repair it?
Bo Dao Nha
-@KG4

Hello KG4, and welcome to expat.com.

The member you are replying to has not been active in over 5 years, so it is doubtful you will receive a reply from them.

I suggest you visit the forum's main Vietnam page, here, and open a new topic. Many helpful folk here at expat.com.

Again, welcome aboard and hope to hear from you again soon.