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09 dr-z400s throttle issue

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I just bought this bike, 09 dr-z 400s. I have an issue. She starts easy, with out choke,I let her warm up for a couple minutes, when i take off, every things seems normal in first gear,Then when i shift into 2nd gear, she stalls. I have replaced the existing gas, with 91 octane,Tried it again and i have the same issue. This bike is stock. No mods as of yet. I looked at the air filter area and theres thick oil everywhere. The bike supposedly was just serviced. But sat for a couple of months after, before i bought her. Any thoughts?

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Fresh gas. Service the air filter. Carb might need a fresh cleaning. Smell the oil for gasoline smell. Calif vapor emissions intact or removed? Gas tank over filled will saturate the charcoal canister. If the canister is removed, is the tank vented?

Does the petcock reliably turn the gas off when set to ON or RES motor not running? Don't park it with the petcock set to PRI. Often the carb will need a new O ring on the float valve seat to cure leaking/flooding. 8mm by 1.5mm or 5/16" by 1/16".

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The Gas is fresh, When I looked at the air filter ,more closely,It appears that its a stock air filter from 09, Calif vapor is intact,Only 1 gallon of fresh gas, Not sure about the tank being vented? As far as the petcock, The guy i bought it from says he only ran the bike in the PRI position. And thats how it was when I first looked at it.

As far as the O ring in the carb, No leaks- What do you mean by flooding, Bogging out when getting in to 2nd gear? And then stalling out?

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OK so it is an S, CA model, stock, Mikunji carb, Vapor canister intact. Tank is vented via the canister. Not over filled, Fresh gas. All sounds good so far. But petcock on PRI is not right. Do you understand the petcock system? It is a vacuum operated petcock. When set to ON or RES it is automatically shut off when there is no engine vacuum. Engine vacuum automatically turns the gas on. PRI (Prime) bypasses the vacuum system so gas will flow without engine vacuum. Such as to refill a dry carb. So by leaving the selector lever on PRI the gas is never shut off (and there is no reserve)

The carb is likely gummed up. And the engine oil is likely contaminated with gasoline. There is no high fuel level drain on the carb so gas that leaks past the float valve winds up in the crankcase. It is also possible the oil system is over filled. So change the oil. There is a procedure in FAQ. Remember drain both the frame and the engine. I'm not sure what you are telling me about the air filter so wash it out in solvent (gasoline) and re-oil it, squeeze out all the excess oil that you can.

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I did some research on the petcock, (Fuelcock). I understand now. Also thanks for all you input. Last night i put in 2oz of SEAFOAM, ran it for 10 mins at idle, let it sit all night,

This morning i took the air filter out, ran the bike for about 10 mins, shut it off then ran it again about an hour later for 10 mins. With no air filter again. In my garage, It seems to be running alot better.

Now weird question concerning running without an air filter, Is it possible its getting to much air to fuel ratio?

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Noble, your good, i just smelled the oil and its contaminated with fuel.... I am going to change the oil tomorrow after work. Any recommendations?I'm not a daily Rider yet! As far as a new air filter,Do you recommend K&N or is foam filters ok?

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Foam filters filter better. K&N OK for paved road use. Foam for dirt.

Recommendations on oil? 10/40 or 20/50 motorcycle oil. Synthetic preferred. Many people swear by Shell Rotella T6 5W40 available Wall Mart. I use Amsoil.

You will want to test the petcock to verify it shuts off. Pull the fuel hose of with it set to ON (motor not running). Run a hose in to a catch container and let it sit overnight.

Might still be a good idea to clean the carb and replace the float valve seat O ring.

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Good advice... 👍 ...

many owners change to a manual petcock, though you just have to remember to turn it to "off" when not in use....

Or remember to turn it on before you race for pink slips :banghead:

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Noble, your good, i just smelled the oil and its contaminated with fuel.... I am going to change the oil tomorrow after work. Any recommendations?I'm not a daily Rider yet! As far as a new air filter,Do you recommend K&N or is foam filters ok?

Well oiled foam for sure

Edited by backyard hack
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I changed the oil, installed a new UNI foam filter, Tested the pet cock in on position over night, no leak or drip. I was giving the engine area a look with a flash light, I happened to see that the Hose clamp that goes from the front of the carb to the engine was loose, like someone loosened it to remove or did and never retightened the clamp. Not sure if this was part of the issue, but after doing everything that was suggested by Thumper talk help, My Bike seem to to run great, I put at least 7 miles on her today,no stalls, responsive throttle, I can finally get her on the ROAD! All or any comments are welcome.

Thanks For all the Supportive help. And it only cost 66 dollars.

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