Carbs flooding cylinders

[rustyshackelford]

First, thank you for taking the time to read this and help me out. I recently got a 2007 250 and am very much still in the learning process about working on motorcycles and appreciate everyone's help and feedback.

So my bike has been running oddly and a few days ago I decided to clean the carbs. When I took off the carbs gas dripped out from where it goes into the left cylinder (the right cylinder was normal) which did not seem right at all. I cleaned the carbs according to the faq and reinstalled them. I started the bike but it was still running poorly like before. The next morning when I tried to start it it wouldn't budge.

Based on a coworker's advice, I pulled the spark plugs and hit the starter and it spit up a good bit of gas- must have been hydrolocked. So just a few minutes ago I pulled the carbs off again and this time gas dripped out from where it goes into the right cylinder (the left cylinder was normal).

Any ideas on what's going on? My coworker thinks its an issue with the floats, but since the excess gas dripping out from the cylinder changed sides (and I may have switched the jets to opposite sides when cleaning) I think it may be a jet.

Thanks again for any advice and help!

[ducatiman]

this is usually a float/float valve issue

[rustyshackelford]

Originally Posted by ducatiman

this is usually a float/float valve issue

The floats look like they are in perfect shape - no holes to cause them to fill and sink. I haven't looked at the float valves so I am going to try and take a look at them tomorrow

[csmith12]

Even if the values look fine, they still need to be checked for proper adjustment or "perfect" float valves will not close and still allow fuel in.

[jkv45]

A few things need to happen in order to overflow the carbs enough to dump any amount of gas into the cylinders.

The job of the float valves ("needle and seat") is to stop the flow of gas when the floatbowls are filled. Something usually gets stuck in the valve and stops it from seating.

The secondary valve that stops fuel flow when the engine is not running is the petcock. It requires engine vacuum to open and allow gas to flow.

Both of them need to fail in order to dump enough fuel in the engine to hydrolock it.

You should look in the tank for rust, and confirm there is a filter in the fuel inlet at the carb. Many people feel using the OEM-type inline filter (https://faq.ninja250.org/wiki/File:Fuel_Filter_4.JPG) is a better way to go than using the type you place in the fuel line after cutting it.

Most likely you will need to rebuild or replace the petcock.

Check you oil level. Many times the gas will get past the rings and contaminate the oil. If your oil level is too high, it's got gas in it.

There's a lot of related info here - https://faq.ninja250.org/wiki/Intake

[rustyshackelford]

Originally Posted by jkv45

A few things need to happen in order to overflow the carbs enough to dump any amount of gas into the cylinders.

The job of the float valves ("needle and seat") is to stop the flow of gas when the floatbowls are filled. Something usually gets stuck in the valve and stops it from seating.

The secondary valve that stops fuel flow when the engine is not running is the petcock. It requires engine vacuum to open and allow gas to flow.

Both of them need to fail in order to dump enough fuel in the engine to hydrolock it.

You should look in the tank for rust, and confirm there is a filter in the fuel inlet at the carb. Many people feel using the OEM-type inline filter (https://faq.ninja250.org/wiki/File:Fuel_Filter_4.JPG) is a better way to go than using the type you place in the fuel line after cutting it.

Most likely you will need to rebuild or replace the petcock.

Check you oil level. Many times the gas will get past the rings and contaminate the oil. If your oil level is too high, it's got gas in it.

There's a lot of related info here - https://faq.ninja250.org/wiki/Intake

That is some super helpful info thank you. There is a fuel filter and no rust in the tank. There is gas in the oil though which I will be changing several times to flush it out (and replacing the oil filter). Is there anything else I should do to make sure there isn't any gas left?

I drained the tank not long ago because I thought the gas might be bad. When I did so I just turned the petcock to on and let the gas flowed/trickle out into a bucket. So since gas came out of the petcock without the bike running I guess I have a bad petcock and will be replacing that.

Is there any way to tell if the float valves are bad. I did not see anything about how to check them on the faq.

[jkv45]

Originally Posted by rustyshackelford

That is some super helpful info thank you. There is a fuel filter and no rust in the tank. There is gas in the oil though which I will be changing several times to flush it out (and replacing the oil filter). Is there anything else I should do to make sure there isn't any gas left?

I drained the tank not long ago because I thought the gas might be bad. When I did so I just turned the petcock to on and let the gas flowed/trickle out into a bucket. So since gas came out of the petcock without the bike running I guess I have a bad petcock and will be replacing that.

Is there any way to tell if the float valves are bad. I did not see anything about how to check them on the faq.

Draining the oil and replacing the filter once should be adequate. Any gas that's left (it isn't going to be much) is going to evaporate when the engine reaches normal operating temp.

There are petcock rebuild kits out there, but last I heard they were almost as much as a new petcock. Aftermarket petcocks without the vacuum diaphragm are out there too, but they are a pain (doesn't stick down below the tank as far as the original and you need to remember to shut them off manually all the time - we had one - I would avoid them). Check around, there may be more options on kits and better prices on OEM ones out there now.

I would plan to install a rebuild kit in each carb, which should come with new float valves. Check the float levels to be sure they are correct and not causing the overflow by not closing the float valves when they should. Search for info on the best rebuild kit to get, or contact ducatiman here to purchase it from him. He can do the entire job (cleaning, rebuilding, adjusting) as well, if you don't want to.

If you decide to do it all yourself, read-up on it carefully - it's easy to miss a few details that will cause problems later.

[adouglas]

I wouldn't swear to it, but I thought pregens had a traditional "faucet" petcock, not the automatic vacuum-operated one found on newgens.

FWIW my vacuum petcock failed, which I discovered when I tried to drain the float bowls. Fuel just kept on running.... so the only thing keeping it from flooding was the float valve seats.

[Triple Jim]

Pregens have a vacuum petcock, but there is no "prime" position, rather an "off".

[Lazarus]

Same thing happened to me. The tips of the float needles can shrink, crack, decide they don't want to work that day, you name it it could probably happen. (Darn Murphy and his law) my petcock also was leaking.

Rebuild the petcock, get new float needles, change oil, go for a ride, dismount and crack beer for celebration. Too bad everyone else beat me to this explanation haha

[rustyshackelford]

So the consensus is new petcock and float needles. Now I have a good idea of what the answer is going to be, but I'll ask anyways. A new Kawasaki petcock is ~$90 (a bit less for rebuild kit) and Kawasaki float needles are ~$35 apiece. On ebay I found a petcock for $10 and float needles for $5 apiece. Am I setting myself up for disaster if I go the cheap ebay route?

[Z1R rider]

Originally Posted by rustyshackelford

So the consensus is new petcock and float needles. Now I have a good idea of what the answer is going to be, but I'll ask anyways. A new Kawasaki petcock is ~$90 (a bit less for rebuild kit) and Kawasaki float needles are ~$35 apiece. On ebay I found a petcock for $10 and float needles for $5 apiece. Am I setting myself up for disaster if I go the cheap ebay route?

I don't know about the petcock, but I have used the ebay needles without a problem.

[adouglas]

Easy enough to test the petcock...

If it's a vacuum petcock, it should not allow fuel to flow if the engine isn't running.

Try draining the carb bowls with the petcock in the ON position. If fuel keeps on flowing after they should have emptied, the petcock is faulty.

Relevant threads (note: this is for a newgen model, so the part is different... but if it's vacuum operated, the principle behind the 2007 version is the same):

Discussion of symptoms
https://www.ninjette.org/forums/show...hlight=petcock


Solution, with pics of the petcock
https://www.ninjette.org/forums/show...hlight=petcock