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Carb help...

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Ok, this has an old issue I am sure. drz400e with an kiehin fcr mx39 carb. Will run with choke out. push choke in it dies. Give it any throttle at all it dies. pulled apart and cleaned, replaced gas...etc all the typical stuff. Here is the part that should help anyone wanting to give me a solution. Air filter is off and if i spray carb cleaner in the air filter opening then start it it WILL throttle for a brief moment. New main air jet and new main fuel jet. Pilot/slow jet is clean. Petcock cleaned. New valve seat and o-ring. So any ideas? Thanks in advance.

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The condition you describe points to a plugged pilot jet. You say it is clean but that is certainly the usual cause. Probably worth replacing.

On a more generic note, opening the throttle adds air. If fuel is not delivered in proportion, the mixture goes lean and the motor dies. The "choke" is only effective when the throttle closed so when the throttle is opened the "choke" becomes ineffective and if the pilot and main circuit don't take over the motor dies. If the pilot fuel jet is truly not the problem then look for some other problem that will cause the lean condition.

If the choke is left ON, can the RPM be nursed up? If you "choke" the carb with you hand can the revs be nursed up?

What is the float setting? Set with the float touching but not depressing the spring loaded tip of the float valve?

You identify the motorcycle as DRZ400E. What year? Did it come with the FCR? The FCR that came standard on "E's" is not the MX style. It is referred to as the "slant body".

What is the history of this motorcycle? Have you owned it for long? Did this problem just start?

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Have you checked that the fuel screw is turned out at least a couple of turns?

If it was screwed in and seated it would give you a lean condition as you describe.

Like already mentioned, it sounds like your pilot/low speed circuit.

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Thanks for the reply.

it is a 2001 and i was told it was an fcr mx39 but after you saying that it wasnt i have done more research and have found it to be (I think) y/k1/k2 . Not sure if that is describing 1 or 3 carbs. Boy some of these sites I am finding are put together so badly. I am getting so much conflicting info on what carb this is. It looks like the y/k1/k2 but I have not found that info on any other website. Other sites are saying it is an fcr 39 or an fcr mx 39.

I have owned it for a few years and have not added anything to it. It is not stock though. It did sit for a year so I figured it was the carb. I did pull it apart and replaced some things but not the pilot. I will try that and cross my fingers. If this is not and fcr mx then I may have got the wrong valve seat...crap! The fuel screw is turned out 2 turns.

Do the accelerator pumps every go bad? If it did, would it respond this way?

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Post a picture of the carb to verify the type of FCR. But if it is original with the bike, it is a slant body design. Pretty sure the float valve is the same for both types. If it fit and adjusted to spec, it is correct. Float vales do however come in calibrated sizes. You might verify the diameter size (marked on the vale seat) is the same but that is not your problem here.

You will need to buy the correct style pilot fuel jet. Just buy the same as what you have.

Keihin FCR used on Y, K1, K2, etc are all the same. DRZ400E and kicker models used the slant body carb until Suzuki discontinued the FCR on all models.

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Accelerator pumps do go bad. And in several ways. The diaphragm can leak and/or the check valves can malfunction (jam closed, jam open, missing parts). A nonfunctioning AP may cause stalling on quick throttle application. However the motor will respond normally on slow throttle application. I rode my E with no AP for several months.

You can easily test the AP with the carb off the bike. Fuel in the bowl and operate the throttle wheel. (don't squirt yourself in the eye)

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First and formost, if the bike was sitting for over a year then really make sure that the carb is thouroghly cleaned out. Not just cleaned but actually using a wire in the ports to make sure they are free and open. (being careful not to damage it) Then blow air through them. Sometimes it behooves one to replace all the jets as well. I have seen carbs that were green inside from the old gas. Then and only then should you tackle the next steps that are being advised.

You may have already done this but just throwing out my 2 cents. Cheers

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Well pulled it all back apart complete and submerged in carb cleaner this time, rinsed it and blew it dry including all ports. yes I took all the rubber parts off. Put new jets in including the pilot. Now I can get it to idol without the choke but it is very unresponsive and backfires. I checked the valve clearance and it seams fine. Would it backfire throwing flames if it is a carb issue? It acts like it is out of time like an old chev would be but I am not familiar with 4 stroke timing and if it even has an adjustment.

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Might pay go put a new plug in and if you can swap out a coil if your having no luck with the fuel side of things:thumbsup:

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I just cleaned my carb and soaked the shyt out of my air filter when i give throttle it almost quits I got a little to crazy with the air filter oil other than that it purrs like a ***** cat Cheerio!

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Not the plug and not the oil in the filter. Coil have not checked but I think that will be unlikely the problem, BUT, ya never know. Thanks tho.

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Coil can not be tested as such, best just to swap with a known working unit off another bike.

Stupid question, you cleaned the petcock but did you check you had flow?

Pull the MJ access cover bolt and turn on fuel would be the best way.

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