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xr400 carb frustration

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Clean tank, fresh gas, clean petcock, new lines, new visufilter, new jets, new o-rings, carb boiled in sonic cleaner(twice). Starts with full choke, runs for a few seconds, begins running erratically, spits, coughs, dies. Repeat. EVERYTHING cleaned multiple times with ZERO change/improvement. Acts like it runs out of gas. Correct jets, fuelscrew setting, etc. Will never start without choke. Will not accept throttle without choke and then only briefly before dying. What am I missing. 👍

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Intake O ring gasket ?? sounds like way to much air is getting into the cylinder , a stuck exhaust valve ? Decompressor stuck Top end needs a look at .

Leak down test would help.

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Air filter seated correctly?

Intake manifold O-ring there and in good shape?

Float set properly?

How about some info of why you tore into it in the first place.

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Know anyone local with an XR you can switch carbs with to see if a known, working unit will do better? Maybe it's not the carb.👍 If I still had my stocker I'd ship it to you to try but I sold it a while back.

Another thought - is the tank venting correctly?

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Intake manifold has never been removed and is tight. I am thinking valve or de-compressor problem also, but it starts and runs perfectly for a few seconds then acts just like it is running out of gas. Wait 15 seconds and it starts fine/easily, runs a very short period then starts the funny business again. Tore into carb for this reason, just started acting funny after three months of non riding. Will do a leakdown check this week, buddy has the tools needed. Thanks Perc, nice offer. May get back to you. Thanks everyone.

Edited by YHGEORGE

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EVERYTHING!!! Letting another set of eyes take a look. My patience tank has been drained. Thanks again, I'll let y'all know what it was. Even if it is embarrassing!

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+1 on the fuel vent....then i would look at the floats....also check the side plate screws that keep the choke lever in place....i have seen those come loose and cause this too....

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Thanks guys but I did state EVERYTHING! Yes I am frustrated.👍 Bike now up for sale, should last forever.

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Why sell it take it to a bike mechanic you may learn something will be only something simple if you have done all that you have said and checked what has been said here

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Why sell it take it to a bike mechanic you may learn something will be only something simple if you have done all that you have said and checked what has been said here

Frustration level has exceeded my program parameters. Life is short and getting shorter. Thanks anyhow.

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Frustration level has exceeded my program parameters. Life is short and getting shorter. Thanks anyhow.

I don't blame ya. I know you've had troubles with that one for a while now. Part it out.

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I don't blame ya. I know you've had troubles with that one for a while now. Part it out.
Nah, though its a '97 its still barely broken in. For health and other reasons it has sat most of its life. Still original everything except tires. I did the second brake pad change after I got it about a year ago. Just something weird going on with the carb.

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ALERT! ALERT! Late Breaking News Flash!!! This just in---Disgruntled, dispirited, disgusted almost defeated YHG recovers in late rounds and kicks &%# knocking out dastardly young punk. Was bouncing off the ropes taking a terrible beating and corner almost threw in the towel. YHG even declared "NO MAS" but referee(TT) refused to let him quit. YHG marshalls strength for one last round and EUEREKA; what a sight to see. Emerges victorious to the delight of long suffering fans. And your right Rayza, I did learn something. After three manual and two sonic cleanings(one overnight) the pilot jet was plugged again. So I dismantled carb to its bare DNA and blasted again. Newly reinvigorated, incredibly handsome, senior rider deep in the Heart of TEXAS again ready for all challenges!!! Don't let your women near me, got some new lead in my pencil! :worthy: :worthy: YHG now has the easiest starting, smoothest, sweetest running XR4 in all earthdom. Demo rides given free of charge 10/22. Thanks guys, have never had such a frustrating/recurring/simple problem that fought so hard. I knew it was gunk in the carb but it just would not let go. Y'all kept me going.👍:ride::worthy: :worthy: :worthy: :worthy:

Edited by YHGEORGE

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ALERT! ALERT! Late Breaking News Flash!!! This just in---Disgruntled, dispirited, disgusted almost defeated YHG recovers in late rounds and kicks &%# knocking out dastardly young punk. Was bouncing off the ropes taking a terrible beating and corner almost threw in the towel. YHG even declared "NO MAS" but referee(TT) refused to let him quit. YHG marshalls strength for one last round and EUEREKA; what a sight to see. Emerges victorious to the delight of long suffering fans. And your right Rayza, I did learn something. After three manual and two sonic cleanings(one overnight) the pilot jet was plugged again. So I dismantled carb to its bare DNA and blasted again. Newly reinvigorated, incredibly handsome, senior rider deep in the Heart of TEXAS again ready for all challenges!!! Don't let your wives near me, got some new lead in my pencil! :worthy: :worthy: YHG now has the easiest starting, smoothest, sweetest running XR4 in all earthdom. Demo rides given free of charge 10/22. Thanks guys, have never had such a frustratingrecurring/simple problem that fought so hard. I knew it was gunk in the carb but it just would not let go. Y'all kept me going.👍:worthy: :worthy: :worthy: :worthy: :worthy:

:worthy:

HELL YEAH!!! Glad to hear it man!! :ride:

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I have the same problem with my 97 400 the ethanoil pretty much has gotten to the jets and I cannot find a carb kit for a 97 xr 400.I am in zachary louisiana anyone close have a stock carb i can buy so I can sell my bike.I am 63 and it is just too hard for me to start.

thanks pat avery

225 405 5984

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