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XT350 carb setup

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Hi All, I just picked up a near-mint 1990 XT350 with 4900 miles on it. The bike runs as it did from new but I can definitely tell that it is too lean. I have checked the boots that go from the airbox to the carb and they are fine. Is there a common consensus on what to rejet the carb to, or to rejet at all? Maybe just needs the air mixture screw adjusted and a shim added to the needle? Also, if a rejet is needed do you rejet both carbs, or just the primary? Also, the bike has the stock exhaust. Sorry if this has been asked before but all the research I have done has not given me a clear answer.

Thanks

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Adjust the Pilot screw to 2 1/2 to 3 turns out from lightly seated. You may need to drill out the little brass cap that covers it up.

Start there and see how it is.

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checked the pilot screw and it was already set to around 3 turns out. Reset it to 3 turns and took it for a 10 mile ride to warm it up and there seems to be a little stumble at 3500, feels like its not getting enough fuel. I pulled the choke out a little bit, about 1/4 and that seems to fix the problem. Outside temp was around 45~50F.

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That stumble is pretty common on the XT.

Try a 130 main jet and a shim under the needle.(tiny washer, or the eyelet from an electrical connector).

Primary carb only.

Be carefull not to mess up the float level when you pull the bowl off.

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Thanks, I will try that. Do you recommend doing anything to the pilot jet, or just leave it alone? Also, what is the correct way to take the bowl off without throwing the float level off?

Thanks again

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pilot has to be drilled as i have not found anything that fits other than stock. if you do drill the pilot, leave the needle alone as it is fine with a larger pilot jet.

make shure you clean the screen in the carb and the one in the fuel tank. that helps with the bog but it can never be eliminated. i cannot tell you my jetting as mine is modded too much for those # to work as we had to use an o2 sensor to get it jetted right.

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make shure you clean the screen in the carb and the one in the fuel tank. that helps with the bog but it can never be eliminated.

For comparison sake :

My '89 XT350 doesn't seem to have bog at any RPM except it stops making power just above 7500 RPMs . That's not bad , as it acts as a speed limiter . Top speed is about 75 MPH . It's very strong until then . :busted:

I'm running a needle shim with stock jetting and the idle screw at about 2.5 turns out . I do 1/4 choke it until well warmed or it pops every once in a while . And I drilled the exhaust baffle plate just ahead of the spark arrestor . It starts with one kick ; two if I leave it alone for a few days . I also run premium fuel and an Iridium plug .

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I'd leave the Pilot jet alone as long as you have the stock exhaust.

Also, try just the shim like pd350 has. That's done through the top of the primary carb so you don't have to remove the bowl.

The little tube that goes from the bowl to the secondary carb is what makes the bowl hard to take straight off. I usually take the screws out of the bowl and slide the bol over just enough to get the line off on one side. then the bowl can be lifted sreight off without hitting the floats.

FYI, I've also opened up my stock exhaust a little bit by modifying the internals. Same with my air box. I didn't do much though because I didn't want to throw the jetting off too far.

Cleaning the screens like maim said is a good idea too.

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I have no stumble on my XT...

Stock exhaust with no spark arrestor, stock airbox with holes drilled in the cover and snorkel removed, 130 main jet primary carb, 125 main jet secondary carb, no needle adjustments, at sea level. I'm pretty happy with it. It definitely hauls ass compared to stock, especially about 4500 rpm. I do want to open up the exhaust without hacking up my stock exhaust, though. I retrofitted a silencer off a 92 Honda 250X atv (slightly smaller diameter but straight through design) and bolted it on once but it stumbles hard at 7,000rpm. Might try to tinker with that more later.

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So upon taking the carbs off to make the adjustments, both of the rubber boots ripped off the metal pieces that bolt to the motor so I am in the market for new boots. Not wanting to pay 120 bucks for 2 dollars worth of rubber I found that Sudco sells replacement sets for the xt600 that look the same as the 350, and are only 65 bucks. Does anyone know if the xt600 boots will or will not fix the 350?

Thanks

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The 350 and 600 have different part #s and so I would have to believe that they are physically different . How much , I don't know .

I have read that the rubbers can be reattached to the metal ,if the rubber isn't too rough . Search is your friend . :lol:

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