XR50 running lean

Matt Fisher
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Matt Fisher
So the time has come to sell my daughter's 01 XR50. Hasn't been ridden in years.

The problem is it's running lean for some reason. With the choke off snapping the throttle open results in a nasty bog, even stalling the engine. Very slow roll on can get it to rev out. Choke in the 1st position lets the throttle work much better, as does sticking my finger in the airbox's air inlet. It will start and idle fine.

The bike is rock-stock and has very, very low hours (original tires aren't even close to being worn). Fuel is fresh, air filter is clean. Air screw from 1 to 1 1/2 turns out has minimal effect. Raising the needle has minimal effect. The 3 o-rings from the cylinder to the carb have been replaced, as has the one in the carb cap. Sea level, temps from 50-70F.

Suggestions appreciated.

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Matt Fisher
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Matt Fisher 12/30/2016 7:39pm
12/30/2016 7:39pm
Carb is clean. Fuel was removed when it was being stored. All passages blow carb cleaner through them just fine.

Turns out there's no pilot jet in those carbs, and if that circuit were clogged wouldn't it not start or idle very well? I'm having issues with 1/3+ throttle
fulltime wrench 12/31/2016 8:56am
12/31/2016 8:56am
Make sure the exhaust isnt blocked by something. I have seen bikes in storage for a long time have the exhaust filled with dog food and acorns by rodents.

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Paw Paw 271
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Paw Paw 271 12/31/2016 9:30am
12/31/2016 9:30am
fulltime wrench wrote:
Make sure the exhaust isnt blocked by something. I have seen bikes in storage for a long time have the exhaust filled with dog food and...
Make sure the exhaust isnt blocked by something. I have seen bikes in storage for a long time have the exhaust filled with dog food and acorns by rodents.
X2

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Matt Fisher
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Matt Fisher 1/2/2017 4:26pm
1/2/2017 4:26pm
It's been sitting in a garage that is frequented most nights by a cat- certainly no rodent issues. Good idea though.

Issue fixed, but I'm really not sure what did the trick. Pulled the carb and thoroughly cleaned all the o-ring surfaces, disassembled the carb and cleaned/checked all passages. Dropped the clip 2 notches. Annnnd it runs just fine. Blush Not sure what changed, as I had already done all of the above. Blink

Either way, I'm off to get the title from the DMV and then sell it. Thanks for the ideas guys.
Hallzilla
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Hallzilla 1/2/2017 7:53pm
1/2/2017 7:53pm Edited Date/Time 1/2/2017 7:54pm
90 times out of 100 it's carb related with those suckers. The hole in that jet is so damn small, that even just a little ethanol build up can raise havoc. Glad you figured it out. Now onto the next chore. It's always something right ? I just picked up a 1980 xr80 and have been going through the same scenarios. Got it for $200 ! Running good now !
sandman768
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sandman768 1/4/2017 10:31am
1/4/2017 10:31am
Funny, I also have my daughters 01 xr 50 sitting in my garage, Can"t bring myself to sell it....I have not used it since 13 when I brought it to LLynns. It has always been very cold blooded & does exactly what you describe until it is completely warmed up, then it would run fine. I always put startron in the fuel tank. One of the neighborhood kids saw it one day & begged me to teach him to ride it, I told him I had to talk to his parents first......they did not want me to teach him, I was kind of bummed, but, that kid would have driven me crazy if he rode it!

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