2006 yz250 carb issues..help please

[txdiamond17]

I just bought an 06 yz250. The original owner let it sit for 9 or 10 months without starting it. I bought it for a song, knowing there would be issues. I have been out of the dirt bikes for years. I drained the bowl, and let fresh gas run through for a while. The gas smelled horrid. She fired right up and ran poorly for about 10 minutes. I killed it and tinkered around just checking the bike over since it hadn't been run in so long. The next time I started it the bike seemed to be stumbling more. Then it started dying. It will run fine with the choke on, but any throttle at all and it dies. Could I have gotten some junk in a jet which slows fuel delivery until nearly wide open throttle? It will almost die until wide open and she takes off. It willl not idle. I am going to remove the carb tomorrow and disassemble and clean it. If a jet is gummed up, can it be cleaned, or does it need replaced. The bike is completely stock, with very low hours. There are no wear marks on the paint and the tires still have the little things on them. Sorry for the long post, but I want to start in the right place. I am about 2000 ft in the west texas heat. I didn't know what oil to use, so I got some Lucas semi synthetic at oreillys today and mixed it at 30:1 per the manual with 91 octane (the highest pump gas available around here). Also have a new spark plug in as well. Thanks in advance. I am very impressed with this site and all the info. I have been searching and reading all afternoon.

[beuford]

It sounds like the carb needs cleaned, you can clean the jets with carb cleaner spray, but they are cheap to replace.

Blow all the orfices out in the carb and get the jet size numbers off them while your there and see if the are correct for your area if the bike is stock.

Dont take the electronic sensor off the carb.

Also if it still gives you problems then also check that the power valve is moving and maybe compression.

[txdiamond17]

I figure the compression is good, when she winds up it flies. Just no idle or bottom. Is it easier to take the carb off if I take the tank off first? It will be a while before I know what adjustments are good, this bike is powerful...and I love it! Can't wait to get it running good. Is there anything I should be careful of when I disassemble the carb, springs etc prone to flying/falling out?

[Oregon250]

Your carb is your most delicate piece on that bike. Remember how it comes off and apart when you put it back together & install. Drain that gas in the tank if haven't already. Take that carb off and take those jetts of and clean them. Spary the whole domn carb clean. Check your air filter, change plug, fresh gas...good staring point!

[cookiemonsterMoA]

The bike is completely stock, with very low hours. There are no wear marks on the paint and the tires still have the little things on them.

This sentence is making me think its not a 2006 because it has a alumninum and you said the paint is not worn. Or are you talking about the paint on the Pipe?

Cleaning the air filter and the carb shouild get it running.

[Drfletcherdc]

I had the same problem plus mine had a steady stream of gas leaking from the bottom tube of the carb. I took the sub frame and shock off and loosen the front of the carb. The bottom of the carb was held on by philips head screws so I went to ACE hardward and replaced them with allen heads. They are a M4 and 14mm long but ACE only had 12mm or 16mm long (I got both but used the longer bolts.)

I bought a carb rebuild kit because I needed a new needle valve and it was cheaper and came with all the jets. I took off all my jets and blew them out with carb cleaner, replaced the needle valve and reset the float height. Now the bike starts up easy and I don't have any more gas leaking. The varnish from the gas is killer on carbs.

[132]

I had the exact same problem with mine .Mine would start and run great then out of the blue it would not start or it would start with holding the gas wide open or putting the choke on it turned out to be the needle valve all i know it cost a lot of money in gas and entry fees going to races when bike would all of a sudden do this. Rick

[axisv]

At that altitude the stock jetting is too rich. In the current heat out there you should probably be running a 170 or 172 main, needle clip in first position from top, and a 48 pilot. Where in West Texas do you live? I grew up around San Angelo.

[txdiamond17]

I am near Big Spring / Midland. I meant there is no wear marks anywhere on the frame or cases. I just said paint for lack of a better word. The carb comes off today. Thanks for all the help.

[txdiamond17]

HOLY !@#$ I have never seen a carb so gummed up. I don't see how the bike was even running at all. I am going to try and clean this thing up, does anyone have a pic or link to a pic of the inside of the carb. I know where the pilot and main jet are, but where is the power jet? I assume taking all the jets out and a can or two of carb cleaner and some compressed air and I should be able to clean her up. Then After a tank of fuel or two and I will mess with jetting. Thanks for yalls help. I will check back in later, hopefully I don't find any new issues.

[Oregon250]

See if that helps. May want to clean the hose form the tank to the carb, or even the tank, and just start with fresh gas. Also, check your float lever. A float level set too high will cause it to run crapppy in the bottom. If you see it dripping fuel a lot, your bowl could be holding too much fuel. To test, you should be able to lean the bike over about 45-50 degrees until fuel starts dumping. Try cleaning first...May solve all your issues.

[cookiemonsterMoA]

HOLY !@#$ I have never seen a carb so gummed up. I don't see how the bike was even running at all. I am going to try and clean this thing up, does anyone have a pic or link to a pic of the inside of the carb. I know where the pilot and main jet are, but where is the power jet? I assume taking all the jets out and a can or two of carb cleaner and some compressed air and I should be able to clean her up. Then After a tank of fuel or two and I will mess with jetting. Thanks for yalls help. I will check back in later, hopefully I don't find any new issues.

First the power jet is located at the bottom of the carb where the float bowl mounts.

Also if its as bad as you say it is i would replace the neddle valve and the o'rings p\on the fuel mixture screw. Also remove the petcock and check the filter is not clogged.

Here is a link to where you can download a manual for your bike.

http://www.yamahaownershandbook.com.au/lib/download.php?f=1P8-28199-31.pdf

[txdiamond17]

thanks for the link to the manual. i have a hardcopy, but it is nice to print off the page you need when your hands are all dirty. I took the carb completely apart and cleaned it. The main and pilot, the little fuel valve above the float, and all passages. I pulled the air mix screw and cleaned it as well. The entire carb was cleaned thoroughly, although I still didn't find the dang power jet. The jetting was completely stock. After reassembling, the bike ran very well. First kick, and she idled like a kitten. The problem I found was it chokes down in the upper rpms now, and really smokes. I think I am way to rich. Also I think the float needs adjusting, fuel drains out the hose when I really got on it. No leaks at all when it sits, so I think the float isn't hung though. I guess its time to learn how to properly jet a bike now. Thanks for all yalls help. Time to go and try it out.