Getting to the carb?

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#1
What has to be taken off in order to get to the carb on a 04 cr250F? from what it looks like a cable or two, sub frame, muffler, gas tank, side # plates, seat, rubber flanges, 2 carb boots & a bunch of skin. Heck im used to just loostening 2 carb boots on my 2-strokes and sliding the carb sideways to work on....this 4-smoker has NO room and the carb wont budge when I try to slide it sideways. It seems to be hung up on cables and crap.
 
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#2
I don't know if you're taking all the way off or just rejetting and needle . I took off the tank and HEAD STAY only. I turned the carb one way to get the little door that honda put in on top of the carb, a couple allen screws and then 1 more allen screw holding the needle in, much easier than a 2 stroke. Honda gave you a little special tool with a rubber doo dad to lift the needle out. Then turn the carb the other way and the main and pilot are super easy to get to just by taking the bottom drain plug out. If I have to take the carb off, I'd take the subframe off., but luckily I havent had to mess with all those cables. I thought the carb on it was fairly easy compared to 2 strokes. Now checking the sparkplug, what a pain , compared to a 2 stroke
 
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#3
How did you get your carb to slide side to side so easy?? mine seemed pretty darn tight to move when I loosened those 2 boot straps....its seemed as all the cables are in the way in order for it to shift side to side?
 
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#4
Also I checked the spark plug..and it was a black color all around the plug except for the electrode. The electrode was clean as if it was a new plug. Is that signs or running to hot?
 
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#5
I did'nt slide it , I just rotated it counterclockwise to where I could get the top off to get to the needle, there's just enough opening between the frame. I can't see any way to do it without removing the "head stay" at least that's what I call it. You can change the main & pilot jet without even loosening the carb but it's easier to see what you're doing if you turn it clockwise. My plug was wet and black too, I'm experimenting but I went to a richer 42 pilot and much leaner 145 main but I live near the mile high city. The bike starts better now but I have'nt ridden it since I went so lean on the main
Does any one else live in the high altitude country?
 

Hick

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#6
Originally posted by CRSpeedy
I don't know if you're taking all the way off or just rejetting and needle .


All jetting changes can be made with carb on the bike. To get at the needle remove the tank and seat. The main and pilot are accesible from the bowl drain, you may want to rotate it out the left side to get a good look, or use a small mirror, to help you get the pilot out...

Hope this helps.
 

Hick

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#7
Originally posted by CRSpeedy

Does any one else live in the high altitude country?

Hey Speedy, I ride my '03 at 4,500 ft and have good luck w/ these settings:

168 main
40 pilot
EKS needle (Honda PN: 16204-MEB-671) at clip # 4, this works out to 1.5 clips leaner than stock.
My fuel screw is a bit richer now that it has cooled off, probably at 1.75 turns.

If you really have a 145 main in an '03 I would go to at least a 160, that is pretty lean. Also, in my experience/opinion, the pilot and clip position make the most noticeable difference at altitude. If you haven't done so already try a leaner pilot by one or two sizes and one or two clips leaner on the needle.

The optional needle I'm running is also one size leaner just off the pilot. If you have an '04 I suspect, but am not sure, they have multi-taper needles so all bets are off as far as running what is working in my '03.

Hope this helps.
 

Hick

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#8
Oops, my bad make that EKS # 3 which is 1.5 leaner than ELR (stock '03) # 5. The "K" vs. "L" is 1.2 clip richer, so 2 clips leaner is really 1.5...

I'm easily confused.


I do keep track of clicker and jetting changes in my manual, but I don't have that here with me... :o)
 
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#10
I got word from a reputable mechanic that I should only have to change the clip position with an exhaust system change and that I shouldnt have to even mess with the pilot.
 
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#11
I left the choke on to check to see if having that extra rich mixture would make it run better and it did but not perfect...still sounded a bit lean with the hesitant throttle response and a bad pop/bog.
 
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#12
Hey Hick, you said 03, so I guess you are talking about the CRF450, right? Mine's the 250 and I thought your main jet #'s sounded way too big. The bike came with a 160 but according to the book , that's for sea level to 1000' and 0 to 20ºF. i guess Honda wasnt taking any chances. I actually went 1 richer on the pilot to ease cold starts and now have a 148 ,NCYR#4 clip. We have a local race Sat. ,I'll see how it runs then.
I did notice today for the first time that if either the CRF or the YZF 250 , even after it's been running for more than 10 minutes , if you pin the throttle , from idle, in neutral it will kill both engines if you don't back off. These are my 1st 4 stroke racers, is this normal. If not do you think it's too lean or too rich? Clip pos?
 

Hick

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#13
Originally posted by High Lord Gomer
I'm pretty sure they are both talking about the '04 CRF250, not the 450.
DOH!!!

Open mouth, insert foot.

Sorry guys, disregard all my posts.

I was wondering why you were twisting the carb to get at the needle.
 

Hick

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#14
Originally posted by CRSpeedy
I did notice today for the first time that if either the CRF or the YZF 250 , even after it's been running for more than 10 minutes , if you pin the throttle , from idle, in neutral it will kill both engines if you don't back off.
That sounds normal to me.

In an attempt to redeem myself I'll offer this:

Ignore what the bike does in neutral. If you are chasing after the best throttle response right off idle try a few quick wheelies in first from really low speeds (clutch out), adjust your idle mix, and try again.

To get a good baseline idle mix, warm the bike up thoroughly and try to get the highest idle speed you can by adjusting the idle mix. Then try some quick roll ons.

The needle clip will be felt at higher openings. You should be able to feel when you "come on to the taper" at about 1/3 throttle. If it falls on its face at this point then you may try adjusting the clip.

My apologies for not reading the questions more thoroughly.

Hope this helps.
 
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#15
That's ok Hick, thanks for respondin to the crack throttle in neutral issue. I've noticed the CRF 250 will wheelie w no clutch almost from idle but the YZF250 has to have more RPMs or speed or more "in the powerband". To improve this, do you think I need go richer or leaner on the clip or something else? Thanks