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Drz-400 help

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Hi guys. I am fairlee new to bikes and need some help. I bought a 2003 drz 400 with a 1000 miles on it. when I bought it the bike wouldn't start. took the plug out and it was black with crud and had no spark. put a new plug in and the bike fired right up. I have had diffuculty starting the bike several times as it does not want to fire at all, but most of the time it fires right up and runs awesome with no hesitation. The biggest issue I have is that it will run for a good 15 minutes, all the while it couldn't run any better, then it will quit as if it ran right out of fuel. I choke the bike, fire it up and take off again, great for a few minutes, then a repeat. Any ideas. this is all happening on a fairly smooth gravel road. Thanks!

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Hi guys. I am fairlee new to bikes and need some help. I bought a 2003 drz 400 with a 1000 miles on it. when I bought it the bike wouldn't start. took the plug out and it was black with crud and had no spark. put a new plug in and the bike fired right up. I have had diffuculty starting the bike several times as it does not want to fire at all, but most of the time it fires right up and runs awesome with no hesitation. The biggest issue I have is that it will run for a good 15 minutes, all the while it couldn't run any better, then it will quit as if it ran right out of fuel. I choke the bike, fire it up and take off again, great for a few minutes, then a repeat. Any ideas. this is all happening on a fairly smooth gravel road. Thanks!

with only 1000 miles on an 03 id guess it sat for a long time. clean the carb and filter and see how it runs after that. maybe new gas in the tank if its been in there a while?

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Ok thanks. The guy I bought it from supposedly had it running and going right before I bought it. and had run it all the previous year, but maybe sitting over the winter let the carbs get dirty? The funny thing is it runs like a top with no hesitation or dogging through all the gears, and I can best describe it as hitting a kill switch with no warning.

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For any bike that's new to me, I do a complete service. Change ALL fluids, lube the linkage/steering stem bearings, check spoke tension and wheel trueness, verify mods done, clean carb/check current jetting, check valve clearance, repack silencer, ect. I'd give the carb a good cleaning to start to verify jetting.

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Kinda sounds like a fuel tank vent problem or petcock problem.  Try it with the gas cap loose. Try it with the petcock set to PRI.

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Ok thanks. I will check this all out and let you know how I made out!

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Also check for a failed petcock/fuel in the oil. The oem vacuum petcock is a common failure item & on an '03 I would replace it now since it can cause all kinds of problems.  

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I only can find 1 line on my petcock that goes to the carb. I can definately smell gas in my oil when I pull the oil cap. how can this happen if there is no vaccum line? or maybe I just dont know what I am looking for. 

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There is also no "prime" on my petcock. I have an on, off, fuel, and reserve. thanks for any help!

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So the petcock on my bike is a manuel petcock with no vacuum. I have figured out that it is a drz 400 e model converted to street. I am going to change my oil and clean the carb and see what happens this weekend. Ant other thoughts welcomed!

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Ok, first test the petcock in the "off" position and make sure it is not leaking. If it is not, then someone left it "on" while parked and fuel went through the needle valve and flooded the oil. So next you need to pull your carb and replace the needle & the valve body O-ring. Can you post a pic of your carb so we know which one you have on there? E, S/Sm used different carbs

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So I cleaned the carb and put back together, still ran horrible and could hardly drive. I took back off and adjusted the fuel air screw, took for a ride and not much better. put the seat back on and it ran like a top! ran great for an hour and then quit right out with no warning. I re started the bike and it ran good for 20 mins, then started back firing and sputtering whenever I let off the gas, then eventually died again. It is somehow loading up with fuel I think, but cant figure it out. could this be a weak coil? something with the valves?  Can't figure out how to post a picture, if you could help me with this, maybe I will be able to post the 2 pictures that I took. The to of my carb sais flat cr on it if that helps.

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I flushed the tank and got a little dirt out of it. The petcock is working well if thats what you mean by fuel flow?

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First off which carb is it? Stock Mukuni or stock FCR/Kiehen? Have you drained and replaced the oil and filter? Did you drain and fill the gas tank with new fuel? Are you sure you cleaned the carb properly? Yes there is a right and wrong way to do it. If Mukuni carb be sure to check/ replace the float valve seat, needle and o-ring. Check ACV diaphram for cracks. Is the battery at full charge? Have you checked all electrical systems functions? As it runs for a bit then dies I would be concerned with the stator function as well. Bike gets warmed up to hot then dies. After a few it starts and runs then dies again. Just so many things to go through.

 

Can you hold up your bike closer to the computer so we can get a better looksee...;)

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One thing I did notice with the bike is that it still ran like crap after I cleaned the carb, until I put the seat back on covering the air box. It instantly ran awesome for about an hour. I dont know if this could tell us something?

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one thing I did just notice is that I cant suck or blow through my vent hose on my gas cap, is this normal?

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I can't help ya on an FCR as I have never been inside one...someone else will have to chime in. 

 

What I was saying before, if your petcock is still leaking, then changing the oil won't help because it will get contaminated with fuel quick. You need to verify what jetting is in your carb...Craigo can help ya there once you report how it is currently jetted.

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I think I may have had a vapor lock on my bike. I took the gas  cap off and couldn't blow through the vent hose, after a while of playing with it i could blow through. I rode with the gas cap loose and had no problems in about a half hour both ways. I sat with my bike iding for about 15 mins to get out of the rain, and the coolent overflow was boiling. I think this is normal for this bike? I will take it for a good lond ride soon and see if I get the same results.

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