Is my motorcycle engine flooded? WTF is going on. Gets harder to start each time?

Question

I recently got a 1980 CB900C from a guy that appears to have taken care of it. My first time starting it..it started fine and I took it for a drive. The second time 3 days later it was hard to start but I eventually got it going. Today I got it to turn over after a few tries and it idled OK but then I moved the choke and it died ( guess I was impatient ) anyhoo I kept trying to fire it up with full choke on and it wouldnt start. Got a couple sputters. So I put the petcock on reserve and got a big backfire ( oops ) anyhoo. Does anyone know whats going on? Am I flooding the engine? This is a honda and they are cold blooded. My starting procedure is: Turn fuel ON, open choke all the way and press Start! I doube it matters but the first time it started fine it was on a flat surface for a few days. Lately its been on a bit of a lean. Maybe the carbs dont like this? If I flooded it, will simply waiting a day fix it or will I have to remove the plugs and crank the engine?

THANKS

Answer 1

them things are notorious for floodin, and foulin plugs when you do............learn how to choke it, without floodin it.........and dont go turnin screws on them carbs, if it ran good before...............

Answer 2

First of all be very careful not to turn the engine over(start) if you suspect that the cylinders are flooded. You're taking a chance of locking up the engine because liquid is not compressible and you may further damage the engine. I suspect that the the petcock may be clogged or that the gas cap vent may be blocked. Both can be checked easily. First of all , at the petcock there should be a strainer to block the large peices of junk that accumulate over time at the bottom of the tank. Carefully siphon the gas from your tank and remove it from the bike. Make sure that you make note as to where each tube is connected. If you have a manual so much the better. Once the tank is empty, carefully unscrew the petcock and rinse using carb or brake cleaner(spray can). While the tank is off the bike you should have access to the carbs. At the bottom of each carb is a screw carefully remove one at a time and inspect the drainnings to see if there's any junk(sand or flakes). If you find stuff, chances are that you will need a carb rebuild. Depending on you're skills it's a do it yourself or a trip to the shop! If there's no junk replace the screws into the carbs. Replace the petcock after it's dried from the cleaner(be careful to make sure that the gasket is in good shape otherwise you'll have a leak!) and replace the lines as you have noted. While the tank is off make sure that the vent line is not pinched or collasped. If it is, often time when you crank up the engine a vaccum foms in the tank and no gas will flow. A bike from the 80's is gona have a few problems but with a little patience you'll gain knowlege and a few skills ...all the fun in owning a motorcycle.

Answer 3

Start by replacing the spark plugs. Backfiring is almost always a sure sign of fouled plugs. If the plugs foul up again or still will not idle get a carb clean.



If the problem is, in fact, your starting procedure and you are flooding the motor you can clear it out by holding the throttle at full open and cranking the starter.



Motorcycles don't flood like old cars did. Flooding is usually a sign of several things.



1. Worn float valve

2. Improper float height

3. (as I learned the hard way just recently) a restricted intake

4. Choke circuit malfunction

5. Jets fell out



First check your air cleaner. If it is not excessively dirty or filled with oil or mice living in it then take your bike to the shop for a carb clean and have them inspect the float valve and choke circuits.



Generally when a bike has been sitting it will start the first time you try. But, that will stir up the funk in the carbs and clog the idle circuits so it won't start again.



It could also be you are leaving the choke on for too long.

Answer 4

Ok, the backfire would've indicated to me that it did indeed run out of fuel in main supply. It never seems to start as good when on reserve as compared to main on the petcock. Mine does the same. Start procedure sounds right, but as soon as it starts you can pretty well start pushing the choke back in.. Maybe some fresh gas? You never did say if you put any in. You just got the bike. (Maybe they finished pissing in the tank so it takes awhile to get that out). "Geezs, rookies!" Remove the plugs, and lay them beside each cylinder and compare. Tells you alot about the engine condition right off.(and whether the plugs are firing).

Answer 5

When you get the bike started with the choke on, start riding it.

While you're riding, slowly turn off the choke in increments until the engine will idle without the choke.



By not using the proper starting procedure, the spark plugs probably

got a little fouled - making it harder and harder to start each time you try.

In the process of trying to start the engine with fouled plugs, the battery gets a little more drained - adding to the hard starting.

Change the spark plugs and charge the battery.

Answer 6

Sounds flooding problem Try not opening choke full all the time esp. on a warm day. Check the floats in the carbs are opening and closing properly. If not spray a light oil into them. If you like remove a plug or two and let sit for a while to dry it out.

Answer 7

Got the same kind of behavior out of my '95 VLX this winter. The culprit was a low battery that would turn the starter but wouldn't fire the ignition.

Check for corrosion where the negative battery cable bolts to the engine.

Answer 8

Turn the choke off open the throttle all the way and crank it if nothing try 1/2 choke

Answer 9

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