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93 cr250 quick question

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I was wondering if anyone could help me out? the bike starts and runs, just wont idle. carb is clean, just gotta keep it revving or it dies. any ideas would be appreciated. are there any usual suspects that i'm missing on this?

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Clean your pilot jet, then mess with the idle and pilot screws, one gives it air and one gives it fuel. It's about finding a balance to make it idle

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thanks for the reply, i'll give it a try today and see if I can find the sweet spot.

 

Clean your pilot jet, then mess with the idle and pilot screws, one gives it air and one gives it fuel. It's about finding a balance to make it idle

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You do realize that the choke knob does double duty as the idle speed knob (rotate to adjust speed), right? Not trying to be a smartass, but its not as obvious as the dedicated idle speed screw used on later PWK equipped CRs.

 

I've never found the idle speed adjustment knob on Keihin PJ equipped CRs to be very effective.  An OEM 2000 CR250 Keihin PWK is a direct swap into your '93 and has a regular idle speed screw. Plus, the bike will run more crisply as a side benefit. 

Edited by RealityCheck

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Clean your pilot jet, then mess with the idle and pilot screws, one gives it air and one gives it fuel. It's about finding a balance to make it idle

 

There is no idle screw.  Idle speed is adjusted via rotating the choke knob.  Idle mixture is adjusted via what the Honda service manual calls the air screw.   If the OP is turning a screw thinking he's adjusting idle speed, that's a problem.

 

To the OP, the OEM spec for the air screw is 1 3/4 turns out.  Start there and rotate the choke knob to get the idle speed in the ball park.  Honestly, I've never had much luck getting Keihin PJ equipped bikes to idle for any length of time without adversly affecting jetting.  Back in the day, my friends and I all owned Keihin PJ equipped CRs and just made peace with the fact that they would only idle for a few seconds when jetted properly.

 

If the bike has both an air screw and an idle speed screw, it's not the OEM Keihin PJ carb. 

Edited by RealityCheck

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There is no idle screw. Idle speed is adjusted via rotating the choke knob. Idle mixture is adjusted via what the Honda service manual calls the air screw. If the OP is turning a screw thinking he's adjusting idle speed, that's a problem.

To the OP, the OEM spec for the air screw is 1 3/4 turns out. Start there and rotate the choke knob to get the idle speed in the ball park. Honestly, I've never had much luck getting Keihin PJ equipped bikes to idle for any length of time without adversly affecting jetting. Back in the day, my friends and I all owned Keihin PJ equipped CRs and just made peace with the fact that they would only idle for a few seconds when jetted properly.

If the bike has both an air screw and an idle speed screw, it's not the OEM Keihin PJ carb.

You're right, my bad I'm stuck on airstrykers lol

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thanks for the help, got her to idle,well, sort of. like realitycheck  said its only for a few seconds before it dies. thanks for the info on the 2000 pwk being a straight swap

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My 96 will idle all day long and I am still rockin the PJ. But, I am interested in a future PWK swap to check out the performance improvements I have read about.

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I finally got the pj sorted out, idles fine now. the only issue I have now is on decel it's making a gung gung gung sound, which I understand to be a rich condition. I have boyesen reeds and a rad valve, and even with new reeds they still don't seal all the way. could this reed cage be causing a rich condition on decel being that the reeds don't sit quite closed on the cage?

one other thing, anyone have some suggestions for jetting baselines? I'm at 8200ft but we ride from 6000ft and up to about 12000ft. the local shop recommends going richer than stock on the pilot and I am confused as to why this would be recommended. I have a 45 pilot in there at 8000 ft and the air screw is within 1-2 turns out and the bike seems happy. so what gives? am I too lean on the pilot?

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They are race bikes not designed to idle. I think it has more to do with the low crank mass than jetting. I never worried about it if the bike runs strong.

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My 95 idles all day long, stock jets, pj carb. I have done the PWK swap on my 97 and boy that thing rips now and also on my 04 and its a totally differant bike now, much more enjoyable, thanks to everyone on here that has helped me out. 

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I finally got the pj sorted out, idles fine now. the only issue I have now is on decel it's making a gung gung gung sound, which I understand to be a rich condition. I have boyesen reeds and a rad valve, and even with new reeds they still don't seal all the way. could this reed cage be causing a rich condition on decel being that the reeds don't sit quite closed on the cage?

one other thing, anyone have some suggestions for jetting baselines? I'm at 8200ft but we ride from 6000ft and up to about 12000ft. the local shop recommends going richer than stock on the pilot and I am confused as to why this would be recommended. I have a 45 pilot in there at 8000 ft and the air screw is within 1-2 turns out and the bike seems happy. so what gives? am I too lean on the pilot?

At least at sea level, a PJ carb should have a #52 or #55 pilot. Even at high elevation, a #45 pilot jet may be lean.

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I have the idle circuit dialed in and it seems to like the 45 pilot at my home elevation at 8200 ft. the air screw is out 1.5 turns, and that's where it wants to be. the bike starts fine and will idle all day long now. the question I have now is about deceleration, I have been told repeatedly that it is a rich condition that will cause the bike to make a gung gung sound, but how can it be rich with that small of a pilot? or is it a little rich on the needle? for what its worth, there is no hanging idle, and it pulls great all the way through from bottom to top.

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Mine idles all day long....and I'm pretty sure they are SUPPOSED to idle.  When you buy it new, they idle.

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mine is idling fine now, when I opened up the carb, I found the pilot jet to be broken. that's right broken. no pieces in the carb, so it happened at some point prior when po had it apart.

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