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1986 CR250 PWK 38

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Title says it all here, I’ve got an ‘86 CR250 I’m putting together and I’m trying to figure out what to do carb wise. Right now it’s got a PWK 38. Anyone run this on the older CRs? What kind of numbers should I use for jets, needle, etc. I’m terrible at jetting, hoping someone can help me here lol. Here’s what the carb has now:

PWK 38mm

158 main

N85D needle

2nd groove from top

38 Pilot

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Got a shop manual ? When in doubt I go to bone stock and work from there. That being said I've noticed *on a lot of threads* the 250's run fatter than the 500's  (PJ 38).  I recall a lot of the mains were in the 170's. Pilots were fatter too, Good luck.

Edited by 87' CR 5003
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I seen your specs in the other piston too. I would definitely go bigger on the pilot and the main. Those both seem on the smaller side. If the bike was used at high elevation before that could explain things.  Start with a 42 pilot and a 165 main and go from there.

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Alright sounds good. How about the needle? Is there a popular one I can use, and where can I get one. I can’t seem to find the Honda 1370 needle anywhere.

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Ok stock carb for this bike was a PJ series.
Effective Venturi size: 38mm
Jet Needle: R1368N
Clip position : 3
Main Jet: 175
Slow/Pilot: 60

That’s all according to the Honda service manual I have. That’s for a PJ carb.

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15 minutes ago, ASP1227 said:

IMG_1931.jpgIMG_1932.jpg

Found this interesting chart in the manual. May be useful somewhere.

Those #'s sound like what I saw, The PWK may be slightly fatter because they flow more, Your float height should be 16mm, and 19mm on the Airstriker.

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Right now the carb has a N85D needle, I think it’s for KTMs, or at least that’s what I’ve seen on the internet. Any recommendations? I was looking at the NEC series of needles.

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14 minutes ago, ASP1227 said:

Right now the carb has a N85D needle, I think it’s for KTMs, or at least that’s what I’ve seen on the internet. Any recommendations? I was looking at the NEC series of needles.

The pj series carbs used much larger pilot jets than the pwk. The main jet wont change much between carbs but the needles are different and can't be interchanged. The r1368 is a "fatt" needle and needs a bigger main than lets say an necx . Im not familiar with the n85d needle. I will try to find you some needle suggestions. 

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The pj series carbs used much larger pilot jets than the pwk. The main jet wont change much between carbs but the needles are different and can't be interchanged. The r1368 is a "fatt" needle and needs a bigger main than lets say an necx . Im not familiar with the n85d needle. I will try to find you some needle suggestions. 

Thank you. I really appreciate that. I’m tying up loose ends on the bottom end and am doing final assembly on the clutch side. Then it’s just the stator and wait for the cylinder to get back from Powerseal. Hopefully December I’ll have it running. Looking forward to enjoy this bike. ;)

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How does the NEDW needle sound? I’ve seen some guys running that on forums, but’s that an ‘06 CR250

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Ok guys I ended up ordering a AirStryker for the CR. The PWK just isn’t doing it for me, seems to be using up fuel like crazy, I’ve checked float height and stuff, can’t tell why. ANYWAYS the Airstryker is on the way, didn’t buy new because money is tight, but it’s a good used one off a good running bike. What do you guys think I should do jetting wise? I’m going to be anywhere from sea level to maybe 2,000 ft max.

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The stock PJ used a 175 main, 60 pilot, R1368N on 3rd clip with 20:1 at sea level.

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On 1/7/2018 at 11:32 AM, ASP1227 said:

Ok guys I ended up ordering a AirStryker for the CR. The PWK just isn’t doing it for me, seems to be using up fuel like crazy, I’ve checked float height and stuff, can’t tell why. ANYWAYS the Airstryker is on the way, didn’t buy new because money is tight, but it’s a good used one off a good running bike. What do you guys think I should do jetting wise? I’m going to be anywhere from sea level to maybe 2,000 ft max.

Ok so your starting over with another used carb that is the air striker version of what you already have, is that correct?

Do you know what year and model of bike this new to you carb was stock on, or is it a aftermarket PWK?

When you get the carb and you look to see what jets, needle and clip position are currently in it, also check to see what # is on the slide. Then check the slide # on your other PWK. 

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Ok so your starting over with another used carb that is the air striker version of what you already have, is that correct?
Do you know what year and model of bike this new to you carb was stock on, or is it a aftermarket PWK?
When you get the carb and you look to see what jets, needle and clip position are currently in it, also check to see what # is on the slide. Then check the slide # on your other PWK. 

Yeah. The PWK that I have on there currently came with the bike when I bought it, I know nothing about it and I’m guessing it came off of a KTM 200. It was in kinda poor condition, which is why I opted for the A/S. The A/S is in much better condition than the PWK.

They’re both #7 slides. The A/S came off of a ‘99/2000 CR250, not sure if it was stock to the bike or not. The A/S came with the following:

220 main
38 pilot
#7 slide
DKA needle on middle clip position

I changed the A/S to the following:

175 main
48 pilot
#7 slide
NEDW needle on middle position

Haven’t ran it yet with the A/S.

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27 minutes ago, ASP1227 said:


Yeah. The PWK that I have on there currently came with the bike when I bought it, I know nothing about it and I’m guessing it came off of a KTM 200. It was in kinda poor condition, which is why I opted for the A/S. The A/S is in much better condition than the PWK.

They’re both #7 slides. The A/S came off of a ‘99/2000 CR250, not sure if it was stock to the bike or not. The A/S came with the following:

220 main
38 pilot
#7 slide
DKA needle on middle clip position

I changed the A/S to the following:

175 main
48 pilot
#7 slide
NEDW needle on middle position

Haven’t ran it yet with the A/S.

For reference, on the right side of the carb, just above the float bowl and below the letters PWK see if there is a number stamped in it. The 99 cr 250 PWK id =00A the 2000' cr 250 PWK =00B. The 99' came with a #5.5 slide and a 1370DKA needle, the 00' came with #7 slide and a A715/289R needle. The stock CR 250 pwk slides came with a small notch in the center of the bottom edge.

Did you notice a notch in the slide?

A220 main seems way too big, even for the fatter tipped 1370DKA needle. 

 

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For reference, on the right side of the carb, just above the float bowl and below the letters PWK see if there is a number stamped in it. The 99 cr 250 PWK id =00A the 2000' cr 250 PWK =00B. The 99' came with a #5.5 slide and a 1370DKA needle, the 00' came with #7 slide and a A715/289R needle. The stock CR 250 pwk slides came with a small notch in the center of the bottom edge.
Did you notice a notch in the slide?
A220 main seems way too big, even for the fatter tipped 1370DKA needle. 
 

That’s what I was thinking. I’ll check the id on the carb, looks like it may be off a ‘99. It had the DKA needle in it.

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The carb ID number reads S66A2EL8. I put it on the bike with the setup I described in the earlier post and I can already tell it’s running a lot better. I haven’t really got to test it by riding it due to weather but initial startup, idling, and throttle response is good. It doesn’t load up anymore or bog. Also it’s idling a lot better and the choke on this carb actually works. I was able to start it with the choke on and it fired up on the 3rd kick. The old carbs choke wouldn’t even stay on.

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19 hours ago, ASP1227 said:

The carb ID number reads S66A2EL8. I put it on the bike with the setup I described in the earlier post and I can already tell it’s running a lot better. I haven’t really got to test it by riding it due to weather but initial startup, idling, and throttle response is good. It doesn’t load up anymore or bog. Also it’s idling a lot better and the choke on this carb actually works. I was able to start it with the choke on and it fired up on the 3rd kick. The old carbs choke wouldn’t even stay on.

S66 is the ID number for the Keihin aftermarket 38mm quad vents air striker. In standard form it came with a 170 main, 55 pilot a DDJ needle and #7 slide. The float height should be 16mm, not the 19mm that was mentioned above. Hang on to that 1370DKA, I ran it in our CR 250 and liked it. Running the NECx in our SX and liking it too, haven't tried it in the CR yet. Just thinking out loud here but my initial thought is you may end up going leaner on the main, the pilot and possibly the clip. Better to start rich and work down though. Are you familiar with the method that utilizes the air screw to determine correct pilot size? 

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S66 is the ID number for the Keihin aftermarket 38mm quad vents air striker. In standard form it came with a 170 main, 55 pilot a DDJ needle and #7 slide. The float height should be 16mm, not the 19mm that was mentioned above. Hang on to that 1370DKA, I ran it in our CR 250 and liked it. Running the NECx in our SX and liking it too, haven't tried it in the CR yet. Just thinking out loud here but my initial thought is you may end up going leaner on the main, the pilot and possibly the clip. Better to start rich and work down though. Are you familiar with the method that utilizes the air screw to determine correct pilot size? 

Loosely yes. If it’s more than 2 turns out the pilot is too rich, and under a turn is too lean. I think that’s how it works, I could be wrong lol. I put it on the bike and ran it. Seems a lot better. Made a video, sorry for the crappy video lol.
Currently has a 175 main, NEDW needle on mid clip, 48 pilot, air screw 1.5 turns out.

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