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XT350 carburetor woes...

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First off, I'd like to say hello to ThumperTalk and all its members.

Ok, I am at my wits end with this carb set-up on this thing .. been trying to get the bike to run right since I bought the thing a year ago. I have went through the carb(s) several times, bought a used one for $90 here in town at a salvage store, and made one decent carb assembly out of the two, or at least I thought so.... the Yamy dealers say they cannot sell me a rebuild kit, and I am at thier mercy of spending $300 or more on a new one!! :cry: Cannot do that(poor college student with baby coming any day), I am convinced there is another way. I have read several posts but nothing is steering me in the right direction. There are NO external adjustments for air or fuel anywhere that I can tell....

Symptoms are:

~cannot get past about half throttle without it cutting out and tufts of black smoke (indicitive of a rich scenario, yes?)

~seems to idle relatively stable, choke works, starts up fairly easy

~secondary seems to be opening when it should...

I have:

~replaced petcock vavle assembly(there was rust present in the screen)

~drained tank several times

~replaced intake boots from carbs to engine

~cleaned the carbs countless times

Shall I:

~give up on this thing, I love everything about the bike except the CARBS

~save up for the overpriced new carb

~hope there is a rebuild kit out there....

PLEASE, if anyone can aid me in my plight to make this thing right, I would SO much appreciate it. ANY input is very valuble to me. :cry:

Mathias maximus0067@yahoo.com

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Bike is totally stock except muffler is uncorked.

Air filter is ok, It's a Uni, recently cleaned/reoiled ...tried running it with out it, just to make sure.

All jets are there, cleaned several times.

Thanks,

Mathias

'85 XT350

'89 CR250

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I am assuming you bought the bike used, it has had this problem since Day One, and nothing you have done to the carburetors has made a bit of difference. The fact that you "bought a used one at a salvage store, and made one decent carb assembly out of the two," is troubling. But for now give carbs a rest and try something else. Don't get your hopes up, these are long shots.

Basics: Put in a new gapped spark plug. Check to see you have a good fat spark. Make sure the plug cap and plug lead aren't damaged. Those resistor plug caps go bad once in a great while; you might try a new one as a last resort.

Next check for exhaust restriction. Pull out the exhaust baffle and see if it looks plugged. Try riding the bike and see if there is any change with the baffle out. If no change, remove the entire muffler if you can and test ride with just the head pipe. Remove head pipe and all if you have to. Don't ride it any distance like this because the engine will run dangerously lean and your neighbors will hate you. Just long enough to see if the problem goes away.

Ignition system next. Check ignition timing. Maybe its former owner set it way wrong or maybe something has loosened and it has come out of adjustment. You could have some strange CDI problem, but in my experience they usually work OK or not at all. A quick and dirty CDI check: Connect an automotive induction timing light. (Helps if the bike has a battery.) Tape the trigger "on." Tape the gun to the handlebars so you can see the strobe while riding. Take a test ride, and run it at the RPM where it is running bad. If the CDI is cutting out, the strobe will cut out too.

I have a few ideas about carburetion too. But try this stuff first.

Mike

'71 AJS 370 Stormer

'73 AJS 410 Project Bike

'02 Honda XR400

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Thanks for the reply, sorry for the delay... we just had a baby boy last week! :)

Ok, I will definitely give those ideas a shot! The plug is new, and the baffle has been removed since before I bought it. So, with any hope it has been too lean this whole time. But the few times it has run good, it pulls nice and strong. :)

Thanks again,

Mathias

'85 XT350

'89 CR250

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im not sure about the 350 but my xt600 had a bad cdi and it would cut out at around 3500 to 4000 rpm's some times it would backfire or just stall and backfire when i tried to kick it. the bike always ran fine off idle and started good but just not handle hard acceleration or running at high rpm. i bought a new cdi box on ebay for $125 and it cured all my problems. i had also read that the xt600 is prone to bad cdi boxes. i am not sure if the 350 is

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I just saw the part about the xt 600 cdi... that just made my day, mine would cut out at 3000rpm. have one on its way now.

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Yeah, I am inclined to belive that it is not my CDI.. it revs smoothly through 3k and past 4-5k... THEN starts crappin' out at those higher rpms on mine... especially when I give it more than half throttle... still gonna look into those other suggestions.

And thanks Black_n_blue! :)

Thanks guys,

Mathias

'85 XT350

'89 CR250

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