Pwk33 help idle

[ivan-083]

Hey guys I just got my 250r back with a pwk33 carb on it. Seems to run good but it won’t idle? Is this the idle screw in the picture below? I went clockwise and nothing happened? Or is it anticlockwise to make it idle higher? Or is the adjust went on top of the choke? Thanks Ivan



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[El Camexican]

That is your idle screw and it looks like you have it turned in pretty far in, like maybe all the way? That shouldn’t be nessesary if everything else is right.

There should be a small brass screw behind your finger in the photo that fits a small flathead screwdriver. That’s your air screw. Turn it in gently until it bottoms out (don’t tighten it!) and turn it out counter clockwise 1.5 turns and see it that makes a difference. Seems to me you might have it turned in all the way already and that would mess up your ability to set the idle speed.

The turning choke idle adjusters were on the PJ carbs.

[ivan-083]

That is your idle screw and it looks like you have it turned in pretty far in, like maybe all the way? That shouldn’t be nessesary if everything else is right.

There should be a small brass screw behind your finger in the photo that fits a small flathead screwdriver. That’s your air screw. Turn it in gently until it bottoms out (don’t tighten it!) and turn it out counter clockwise 1.5 turns and see it that makes a difference. Seems to me you might have it turned in all the way already and that would mess up you ability to set the idle speed.

The turning choke idle adjusters were on the PJ carbs.

I got the bike shop to do the jetting this time, jetting seems to be good and good power! I’ve looked on some threads that you can get a shorter spring? Would that help? Or fix the problem?


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[El Camexican]

I just did some reading and there are guys shortening the springs to solve this problem, so I guess it can be done

[ivan-083]

I just did some reading and there are guys shortening the springs to solve this problem, so I guess it can be done

Yes something isn’t right at all! I did turn it in almost all the way and idle a bit better but look at the plug! Way to rich, I’ll have to take back to the shop and hopefully they can fix it!



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[ivan-083]

I just did some reading and there are guys shortening the springs to solve this problem, so I guess it can be done

Yeah maybe but mine ran for about 20 mins in total, and fouled 2 plugs! Been over 2 years and still not running right! Full rebuild and new carb, same old problem. I give up


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[El Camexican]

Did you check the air screw? Should be turned out 1.5 turns as a staring point and then fine tuned to between 1 and 3 turns out if you have the right slow jet in it.

[ivan-083]

Did you check the air screw? Should be turned out 1.5 turns as a staring point and then fine tuned to between 1 and 3 turns out if you have the right slow jet in it.

I’ll have to look next weekend, guy put in 52 pilot and 158 main jet? Too big?


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[El Camexican]

I’m shooting from the hip here based on experience with other engines, but I would think you would want to baseline that thing with maybe a 162 or 165 Main and 42 or 45 slow jet and the needle clip in the middle.

The size of the main jet will have no effect on your idling, but that 52 pilot would.

There’s all kinds of information on the Internet available on jetting your engine, but given the situation you’re in right now I would put in 42 slow jet, turn the air screw out one and a half turns and see how it runs before doing anything else. While you have the carburetor apart check your float height, on the larger versions of that carburetor I believe the float height is 16 mm, but I don’t know what that one you have should be.

You can also contact Sudco directly and ask them what the baseline settings for that carburetor are. They will not necessarily be perfect for you, but they are an excellent starting point unless you happen to live at an elevation above 4000 feet.

[ivan-083]

I’m shooting from the hip here based on experience with other engines, but I would think you would want to baseline that thing with maybe a 162 or 165 Main and 42 or 45 slow jet and the needle clip in the middle.

The size of the main jet will have no effect on your idling, but that 52 pilot would.

There’s all kinds of information on the Internet available on jetting your engine, but given the situation you’re in right now I would put in 42 slow jet, turn the air screw out one and a half turns and see how it runs before doing anything else. While you have the carburetor apart check your float height, on the larger versions of that carburetor I believe the float height is 16 mm, but I don’t know what that one you have should be.

You can also contact Sudco directly and ask them what the baseline settings for that carburetor are. They will not necessarily be perfect for you, but they are an excellent starting point unless you happen to live at an elevation above 4000 feet.

Thanks I’ll give it a try on the weekend and keep you posted thanks


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[El Camexican]

Before you pull it apart, try turning the air screw out 3.5 turns from closed and see if that makes any difference. If it does help the bike idle then you know you’re on the right path.