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Flooded DRZ

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I relied on this site for a few years now originally to prep my DR for a fantastic trip to Baja - the expertise in the community is fantastic and I have scanned the site over the past couple days and have gotten bits and pieces of info that I have used to remedy my current issue but there is still a couple of answers I cannot find

2000 DRZ400S Yosh pipe and new carb kit - replaced right side radiator from an accident a couple years ago - ran very good as recent as last spring - I also bought a used petcock on ebay to replace what I thought was a bad one and now I wonder if I got screwed on the used one - aftermarket large tank - the petcock is identical to the stock one I had so it must be the vacuum version as it has the nipple for the hose

Question 1 are these stock petcocks supposed to flow fuel continually at all positions? obviously on primer it flows and when in the on position when its on the bike and feeding the carb --- I've got gas in the engine - it blows out the plug hole and the cylinder seep hole - plenty of spark and I have gotten it to fire with the tank off - this last time I actually got it to run a couple of minutes but it did not appear to clean or burn everything out - an unbelievable amount of white smoke tells me I definitely have a flooding problem - so I have gotten it to fire a couple of times but when I put the tank on and hook up the hoses - I get nothing, so it runs on the fuel in the carb (and whats in the motor) but it wont run off the tank source - -keep having to wait for battery to charge up again (it is new but the cranking takes it down)

Any help as to a solution to get it "blown" out and keep it running will be appreciated - I am beginning to think petcock again

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Question 1 are these stock petcocks supposed to flow fuel continually at all positions? obviously on primer it flows and when in the on position when its on the bike

Answer to question 1 NO (this is for a vacuum operated petcock)

Prime position = yes

On position = Gas flows only when the bike is running.

Res position = same as on position.

Best bet is to replace the petcock with non vacuum petcock. If it is flooded like you say you probably have gas in the oil also. You will need to fix the flooding issue and then change the oil.

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Petcock might have a problem, but isn't why the bike won't run. Battleaxe recommends you buy a standard petcock which, yep you guessed it, when on lets fuel run all the time.

In order to have the fuel run into the oil both the petcock must be open and the float valve must leak.

It would appear your problem is the float valve is not sealing thus letting fuel keep running even when the bowl is full, thus flooding the engine, running past the rings, and contaminating the oil. Once the oil is full of gas it often will start but stall once warm as the gas evaporates and the fumes are vented into the intake. E models and some others vent through a hose to the ground, so look for the oil separator box on the right side of the bike above the starter. Also, once the oil is full of gas it doesn't lube very well. This has to be fixed.

Did the kit include the float valve? Dismantle carb. Check the float needle for a groove worn in the tip(replace). Check for junk that might prevent a seal(clean). Check float height (adjust if needed)by allowing float to close against the float-needle-plunger but DO NOT compress the plunger in the bottom of the needle. Carb on its side works best for this. It should be 13mm from the surface the bowl contacts to the bottom of the float. After remedying any problems you find here the bike should run. As long as the float valve never leaks the petcock doesn't matter really. It is a good idea to connect the carb to the tank and check if it shuts off when you lift the float (with bowl off). A 2000 should have the FCR and they have a history of the o-ring that seals the float-valve-seat into the carb body leaking. Then fuel can keep flowing even when the needle is closed and sealed.

Now on to the petcock. You can install a manual one if you want, but then you have to remember to turn it off. The factory one solves this problem with the vacuum operated valve. Engine off, fuel off. The idea here is that with the fuel stopped at 2 places at least 1 hopefully is sealed well enough to stop fuel flowing with the bike off, or laying on its side :smashpc: (a nice feature lacking on the manual one). Like anything the petcock seal can leak and then it doesn't shut off.

The most common way it leaks is the plunger o-ring gets out of shape or hard. There are several phillips screws on the back side of the petcock by the vacuum port . Remove these and pop the back off. If the o-ring looks flattened you might just be able to remove it and turn it over. Worked for me. If it is missing or really bad replace it with a 4mm ID x 2mm thickness (8mm OD) o-ring suitable for fuel. All fixed.

Other way that they fail is on the knob side, the rubber packing can get torn or worn out. remove the screws and knob to inspect. Both the 'smiley face' packing and o-ring are available. If this happened remember to tell yourself "Hey, this could easily happen to the manual ones too, even more since you turn them all the time"

A final way they can leak is the diaphragms on the plunger leak. This will show as fuel leaking out the hole by the vacuum line and if this happens you cannot buy parts so that petcock is done. Rare.

more petcock info and parts numbers

https://thumpertalk.com/forum/showthread.php?t=976487&highlight=petcock+parts

Edited by slowriding

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