07 CRF250 carb help

Craig_Lambrecht
Edited Date/Time 1/25/2012 2:17pm
Hey guys, I tore my carb apart a week or so ago. When I put it back together, I was missing a washer on the air screw assembly. I turned the air screw 3.5 turns out instead of 2 and it purred like a kitten.



Today, I picked up a washer and put it in. I turned the air screw out 2 turns and it fired a couple times with the hot start pulled (barely fired) so I turned the screw out 3 turns and it won't fire at all.

Any ideas?



I've had my bike 3 weeks and haven't even been able to ride it yet. I'm dying to go ride!!!



Thanks Guys!!!
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mxhideout
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mxhideout 1/26/2011 4:29pm
1/26/2011 4:29pm
Why are you using the hot start if the bike is cold? Shouldn't you be using the choke?
Craig_Lambrecht 1/26/2011 4:31pm
1/26/2011 4:31pm
yes..the choke is on as well. I was trying to kick it the other day when missing the washer and had the choke on and it wouldn't fire. I then tried choke + hot start and it fired and ran until I let go of the hot start. This told me that I needed to turn my air screw out more. I turned it out 3.5 and it ran great.
Now, I put the washer in and turned out 2 and won't fire. Even tried it out 3.
Craig_Lambrecht 1/26/2011 5:37pm
1/26/2011 5:37pm
anyone??? please!! Wanna ride tomorrow.
mxhideout
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mxhideout 1/27/2011 1:20pm
1/27/2011 1:20pm
What does the plug look like? Are you using fresh gas?

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FIREfish148
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FIREfish148 1/27/2011 2:52pm
1/27/2011 2:52pm
Put some fresh 92 in it. Bet 5 bucks it runs. Might want to drain the float too if its been sitting long.
mx5471
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mx5471 1/27/2011 3:08pm
1/27/2011 3:08pm
You could try removing the washer and set it the way you had it when it ran to go and ride,and see how it goes. You say you had it 3 weeks and have not ridden it yet,so you must have just bought it. You took the carb apart,for what reason? Did it not start before? If it did ,why take the carb apart? As a mechanic for over 30 years,one of the things I have learned is to question the person having the problem extensively to try to find out the exact problem.It helps to make a good diagnosis and repair. Go thru the carb again and make sure you did it right,and start with stock specs and settings. About the hot start,I once tried to start my Yamaha 450 F when it was -4 degrees. I'm only good for a few kicks.After about 4 kicks I said let me try this. Pulled the hot start and it fired up on the next kick. We were goin indoor ridin in the winter and I wanted to start it before I made the trip. Good luck.
Craig_Lambrecht 1/28/2011 10:15am
1/28/2011 10:15am
thanks for the responses. Yes, I just bought it. It sat with gas in it for about a year. i drained the gas and did a carb clean.
I may try taking the washer out and see how that goes.

thanks again!!

and about the hot start, I have learned that if you choke it, blip the throttle twice, and hold the hot start, 4 strokes tend to fire a lot easier. That's just my experience.

Honestly, haven't pulled the plug. Should probably do that as well.
Craig_Lambrecht 1/28/2011 10:16am
1/28/2011 10:16am
mx5471 wrote:
You could try removing the washer and set it the way you had it when it ran to go and ride,and see how it goes. You...
You could try removing the washer and set it the way you had it when it ran to go and ride,and see how it goes. You say you had it 3 weeks and have not ridden it yet,so you must have just bought it. You took the carb apart,for what reason? Did it not start before? If it did ,why take the carb apart? As a mechanic for over 30 years,one of the things I have learned is to question the person having the problem extensively to try to find out the exact problem.It helps to make a good diagnosis and repair. Go thru the carb again and make sure you did it right,and start with stock specs and settings. About the hot start,I once tried to start my Yamaha 450 F when it was -4 degrees. I'm only good for a few kicks.After about 4 kicks I said let me try this. Pulled the hot start and it fired up on the next kick. We were goin indoor ridin in the winter and I wanted to start it before I made the trip. Good luck.
so, if I run it without the washer and have the screw 3.5 turns out, is that ok? I just don't want to mess it up.
motofab36
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motofab36 1/28/2011 11:44am
1/28/2011 11:44am
You need to go one size bigger on the pilot jet then go back to about 1 1/2 - 2 turns out.

It is a fuel screw not air screw.
Craig_Lambrecht 1/28/2011 2:30pm
1/28/2011 2:30pm
you are correct, it is a fuel screw not air..I for some reason always refer to it as air screw. I actually went one bigger already. It ran fine before but the carb was just all gummed up.
mx5471
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mx5471 1/28/2011 4:47pm
1/28/2011 4:47pm
If it ran fine before,you need to focus on what you did with the carb. I said to run it without the washer because you said it ran good. So ride it and see,temporarily. If it ran good,you took the carb apart,now you have trouble,it points to something wrong with your carb job. If you're going to change all the jetting to get it to run,you are better off to run without the washer,as you said it ran good then. Problem solved. But you really need to recheck your carb work. That's where your answer is.
Craig_Lambrecht 1/28/2011 5:24pm
1/28/2011 5:24pm
all I did was tear it apart and clean the jets..didn't replace anything. Guess I shall tear it back down and see.

Thanks for your responses. I appreciate the help.
xnationalwrench 1/29/2011 9:10am
1/29/2011 9:10am Edited Date/Time 1/29/2011 9:11am
Old school trick is to remove the spark plug and put a thimble of gas into the cylinder put the spark plug back in and if everything is right in the motor it will run til that gas is used up. If this is the case the problem is in the carb. You might have to pull the carb back off and go back thru it but its a learning experience anyway. There are more passage ways in the carb body not just the jets make sure its all clean, take your time and don't rush.
Craig_Lambrecht 1/30/2011 1:50pm
1/30/2011 1:50pm Edited Date/Time 1/30/2011 2:23pm
thanks x wrench! Hey, also...the "sensor assembly throttle" (the little black thing on the outside of the carb)..is that specific in adjustment or anything?



Sorry for all the questions, I just want to make sure I do it right. I have my bike at my Dad's right now so I'm just trying to find out as much as i can before I go over there in the next few days. Also, he's working on it a little too so relaying info to him.



Thanks again!

EDIT: throttle sensor assembly. didn't see the comma on the page I was looking at. :-/
xnationalwrench 1/30/2011 5:01pm
1/30/2011 5:01pm Edited Date/Time 1/30/2011 5:06pm
To my knowledge the sensor is just that, and is non-adjustable. I would recommend getting the shop manual and if that isn't available, at least print a copy of the exploded parts list from anyone of the many on-line parts sources.
Craig_Lambrecht 2/7/2011 10:23am
2/7/2011 10:23am
got it dialed. Went to the track yesterday and it runs AWESOME!
Now, just need to finish dialing my suspension and I'll be good to go.

Thanks again for your help everyone!

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