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2003 YZ250 help

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Hello, working on a 2003 YZ250. Bike has a FMF pipe and silencer with v-force delta 3 reeds and stock jetting. Couldn't start bike because it had 60 psi compression, so I put a new piston and rings in it, and had the cylinder honed, also went through the carb. Now when I start the bike, it will only start with the choke on, and will bog out and die when I take the choke off. Seems weird to me that supposedly it ran fine before he had issues starting it, and it has those mods with stock jetting. The only other thing I did was add a little extra oil for break-in, say about 40:1 instead of 30:1. I haven't had much 2 stroke experience since my old CR125 back in 2004, so any help would be great!

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What did you do when you went through the carb? The slow speed circut in the carb is tiny and sometimes when the jet may appear clean, there may still be something else blocking it in the air bleed or somewhere further down the circuit. If you haven't already, I would suggest removing the carb again and soaking it, along with the jets. I've found the best stuff to use is a water based degreaser called Purple Power, its cheap too. You can get it at a local auto parts store. Soak fully submerged for about an hour, rinse with hot water and spray dry with compressed air through all the passages. Hopefully this helps!

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Soaked carb body, foat bowl, floats and jets in carb clean. Ran wire through jets, only thing I didn't check were the air passages so that's where I'm starting again. Put fresh gas in when I put it all back together.

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Soaked carb body, foat bowl, floats and jets in carb clean. Ran wire through jets, only thing I didn't check were the air passages so that's where I'm starting again. Put fresh gas in when I put it all back together.

You can't use auto carb cleaner on mc carbs.

You will destroy the rubber seals inside ..........!

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And an FYI, I didn't soak the whole carb body, just the area that are exposed to gas if it sits in the carb too long. Like I stated, I didn't check the air passages, only the jets, and sprayed up through the pilot hole to make sure it would make a clean passage out of the carb.

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Got it figured out, blew air from my air compressor through the intake boot to try and dislodge any debris from air bleeds, ran fine. Took subframe off and cleaned airbox side of carb and intake boot, did the trick! Just had to brush off the cobwebs since it's been forever since I worked on a 2 stroke that gave me trouble. Checking the float level height was next on my list. Thanks everyone!

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