Can't get bike to idle

2

2000FLSTF

Member

May 20, 2003

32

0

• Jun 4, 2003

• #1

I just recently purchased a 99 RM250 and don't know the full history on the bike, so I have been going thru it checking things out. I went thru the carb. and found it had a #152 main and has the stock #45 pilot with the neddle on the second clip. It has a PC Platinum pipe.

My problem is, I can't get it to idle and the plug gets wet quick. If I start it and keep the revs up it will run and it seems to run good on the track. Will a simple pilot change to a #42 solve my problem? I've tried adjusting the air screw and idle screw and nothing works. The idle screw is plastic and seems worn, so maybe it's not lifting the slide properly? Is there any throttle cable adjustment I should be aware of?

Thanks

 

CaptainObvious

Formally known as RV6Junkie

Damn Yankees

LIFETIME SPONSOR

Jan 8, 2000

3,331

1

• Jun 4, 2003

• #2

Sounds like the float is out of adjustment. Check its hight from what is called for in the service manual.

 

W

whyzee

Never enough time !

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Dec 24, 2001

2,282

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• Jun 4, 2003

• #3

are you looking for a steady constant idle? If so this may be tough to achieve without increasing the idle speed.
Give a pull on the choke and see if the problem gets better or worse. If better, you are a bit on the lean side for the idle circuits. (air screw & pilot jet)

BTW, I ride an '01 injected Fatboy. Where are ya from?

 

M

Mr. Clean

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Nov 8, 2001

162

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• Jun 4, 2003

• #4

Assuming the float valve is good and the float level is ok my bet is that your pilot jet is too big. I am surprised at how poorly many bikes are jetted especially 125's. This may be ok for a pro rider that rides a track at full throttle most of the time but for most people who putt around sometimes or just can't keep it pinned it can be a problem. I also find the straight portion of the needle valve or the valvle cutaway is too rich on many bikes. I live at almost sea level so it must be worse for most other riders.

 

2

2000FLSTF

Member

May 20, 2003

32

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• Jun 5, 2003

• Thread starter
• #5

RV6junkie - I'll try to check the float level while I'm in there, but the manual isn't real good and I don't have the measuring tool they show in the book. Is there any easy way of checking this or do you have any quick tips on this?

Whyzee - Pulling the choke out does make it worse which leads me to believe I can go leaner on the pilot(slow) circuit. I live in Houston, Tx and ride a carbed 2000 Fatboy. I got some spare jugs of Ebay and bought the 95" flatops and can't decide on the cam. Any suggestions?

Mr.Clean - I do live at sea level (Houston) and it's hot as hell now for the next 3 1/2 - 4 months. This would suggest I go leaner too, right?

 

2

2000FLSTF

Member

May 20, 2003

32

0

• Jun 5, 2003

• Thread starter
• #6

One other thing, I've screwed the idle screw all the way in and still can't get it to idle (it tries when it's hot), that's why I was wondering if there was some kind of throttle cable adjustment or that plastic idle screw was at fault?

Thanks for the replies guys,

 

W

whyzee

Never enough time !

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Dec 24, 2001

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• Jun 5, 2003

• #7

Originally posted by 2000FLSTF
Whyzee - Pulling the choke out does make it worse which leads me to believe I can go leaner on the pilot(slow) circuit.

Click to expand...

Correct, jet down in stages one pj at a time, your looking for crisp throttle response off zero to 1/4 throttle.

I live in Houston, Tx and ride a carbed 2000 Fatboy. I got some spare jugs of Ebay and bought the 95" flatops and can't decide on the cam. Any suggestions?

Click to expand...

Any suggestions? Yea, man I love wrenching on mine. I'd look at the 51mm super bore carb, HTCC heads, 258 or the 260 cam, you are going to have to replace the ignition. sounds fun.
Have not done any motor work on mine ... yet. I've installed a PC3 mapable injection / ignition controller. Lowered an inch, over 10k in chrome. next year the motor may see the 103 kit done with the dual FI unit, only thing I don't like about the unit is replacing the injector pump inside the tank.

One other thing, I've screwed the idle screw all the way in and still can't get it to idle (it tries when it's hot), that's why I was wondering if there was some kind of throttle cable adjustment or that plastic idle screw was at fault?

Click to expand...

take the carb off the bike, check to see if the idle screw is touching the slide when screwed in. maybe someone replaced the screw w/ the wrong one. what carb are using, maybe i can find a part # for a brass idle screw for ya.
keep in touch,

 

Last edited: Jun 5, 2003

2

2000FLSTF

Member

May 20, 2003

32

0

• Jun 5, 2003

• Thread starter
• #8

Whyzee - I think the manual said it has a PWK38PWJ carb. on it. The plastic idle screw does move the slide some, I'm just not sure if it's enough or it's just jetted too rich. I can't believe just going down(leaner) one size from a 45 to a 42 will solve my problem, but these 2-strokes are finicky, so maybe it will.....or maybe that brass idle screw will help too.

As far as the HOG, I'm not sure I'm going to go that radical on the cam. I don't want to have to do the heads right now (not enough bucks) and get tighter springs so I was leaning to a more "bolt-in" cam like a 37B, 211's or maybe the Crane 310-2.

 

M

Mr. Clean

~SPONSOR~

Nov 8, 2001

162

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• Jun 5, 2003

• #9

2000FLSTF - We are neighbors, I live in Willis which is just north of you. You can lean out during the hot months,but I think if it is jetted correctly, rejetting isn't necessary. The only thing I do is adjust the air screw to get it to idle as the weather changes. When you are ready, let me know and we can ride the National Forest in New Waverly. I think it is around to 102 mile marker on I 45 north. I can usually ride Sundays and Mondays if I have a little advance notice.

 

2

2000FLSTF

Member

May 20, 2003

32

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• Jun 6, 2003

• Thread starter
• #10

Originally posted by Mr. Clean
2000FLSTF - We are neighbors, I live in Willis which is just north of you. You can lean out during the hot months,but I think if it is jetted correctly, rejetting isn't necessary. The only thing I do is adjust the air screw to get it to idle as the weather changes. When you are ready, let me know and we can ride the National Forest in New Waverly. I think it is around to 102 mile marker on I 45 north. I can usually ride Sundays and Mondays if I have a little advance notice.

Click to expand...

Yeah, I live down in the Clear Lake area, so we are on the opposite ends of planet Houston. I'd love to go ride the woods with you, but I just got this bike and not having been on a dirt bike in 15 to 20 years I'm still trying to get comfortable with it......so I might be to pokey for you!

As far as the idle problem, I took the carb. off last night and was trying to check the float level(I just posted a float level question so I won't go in to all of that here, but please respond if you have any tips). The needle looked good, but I'm not quite sure on the float level. I also went down on the pilot from 45 to 42, so maybe that will help some.