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Cr500 jetting need some input pwk39mm


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Just put a pwk39mm carb I've got a 170 175 42 and 45 to play with for jetting I can seem to get it started with the 45 in have a 60 also but that seems a little much. Ran fine with old carb just wanted a different set up told this was the best bang for the buck trying to get her done before this weekend for thanksgiveing desert trip !!!!

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Assuming you have a 6.0 slide and a 1368 needle, try a 175 main, 55 pilot with the needle clip in the middle, AS at 1.5 turns out. If Octillo is much warmer than 60-70deg, you may need to drop down one on the main and pilot and raise the clip (drops the needle) 1 or 2.

A 1470 or 1472 needle are much better needles for the 500 motor as they clean up a rich bottom and richen up the lean mid-range a bit.

Also, you typically have to crank in the idle speed adjuster (screw that holds the slide open a tad) quite a bit before it actually starts to touch the slide and raise the idle rpm!

Edited by Eddie8v
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A 38 pilot is waaaaay too small for a 39mm PWK on a 500. I don't know how you can even get the bike to start, run and idle with a 38 pilot. A 48 pilot is too small for most. Perhaps your float level is too high, adding the necessary excess fuel that you need with that 38 in there.

The DGN (1472) was extremely lean on the straight diameter for me.

I'm running a DGK, 38 pilot, 175 main & #6 slide.

@ 400-2000' elevation

Edited by Eddie8v
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I have a dgh needle in my pwk and a 1366 in stock carb slide is a 65 not familiar with slides and interchangeing them to be honest I got her started last night on a 52 pilot 175 main clip in middle as screw one and half turn out and thanks for the good info I will look for one of your recommended needles after the holidays !!

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A 38 pilot is waaaaay too small for a 39mm PWK on a 500, that's why the DGN needle doesn't work for you on its top straight section.. I don't know how you can even get the bike to start, run and idle with a 38 pilot. A 48 pilot is too small for most. Perhaps your float level is too high, adding the necessary excess fuel that you need with that 38 in there.

 

 

No its not waaaay to small.

 

Most would agree the 39 on a cr5 typically takes a 42-45ish pilot. The DGN needed needed 55 to even start. Even with that mess it fell on its face transitioning on to the needle.

I have run every pilot from 35 to 55 and DGK, DGL, DGM and DGN. The mythical DGN is far too LEAN (for me).

 

38/DGK is the only setup that doesnt require dicking with the throttle (cracked to wide open) to get it to start and actually requires the choke to cold start. I can run a 35 in the summer. and The float is correctly set.

Edited by jar944
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No its not waaaay to small.

Most would agree the 39 on a cr5 typically takes a 42-45ish pilot. The DGN needed needed 55 to even start. Even with that mess it fell on its face transitioning on to the needle.

I have run every pilot from 35 to 55 and DGK, DGL, DGM and DGN. The mythical DGN is far too LEAN (for me).

38/DGK is the only setup that doesnt require dicking with the throttle (cracked to wide open) to get it to start and actually requires the choke to cold start. I can run a 35 in the summer. and The float is correctly set.

So you're stating that you can run pilot jets ranging from 35 thru 55 within the usable range of the air screw? That's totally impossible. There's really only 1 or 2 pilot jets that will work to get the air screw near 1.5 turns out and still allow for a usable range of the screw one way or the other to allow for daily weather fluctuations. Just my opinion, but something doesn't sound right with your carb and/or intake tract. Maybe you have an air leak somewhere, for instance. Edited by Eddie8v
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So you're stating that you can run pilot jets ranging from 35 thru 55 within the usable range of the air screw? That's totally impossible. There's really only 1 or 2 pilot jets that will work to get the air screw near 1.5 turns out and still allow for a usable range of the screw one way or the other to allow for daily weather fluctuations. Just my opinion, but something doesn't sound right with your carb and/or intake tract. Maybe you have an air leak somewhere, for instance.

 

lol... not quite. Obviously if i stated the DGN required a 55 to run anything below a 55 that would be impossible with the DGN.

 

To clarify I tried different combinations ranging from a 55/DGN to a 35/DGK.

 

carb is fine, intake is fine, engine holds 8 psi with no change for 10minutes.

 

This is a 52/DGN ...embarrassingly LEAN

 

52/DGL (can you hear the slight lean bog)

 

38/DGL (could make go from too rich to start to lean bog off the pilot in about 1/8 turn on the AS)

 

all of those started without the choke cold and needed to be held wide open hot.

 

 

EDIT.

 

looked over my notes. I was running a 52 not a 55 in the first 2 vids.

Edited by jar944
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I hear what you're saying, but your reasoning implies that the straight diameter of the needle has some fueling input on engine idle and closed-throttle operation, such as starting with the throttle tube closed or idling the bike, BUT it does not. The straight diameter doesn't come into play until you crack the throttle a bit and has VERY little, to no, effect on idle... So, I still feel that you have something amiss in your carb and are band-aid fixing it with jetting changes. I might assume the carb is older and worn a bit? Internal air/fuel leak somewhere? Float needle and seat set are not sealing, allowing extra fuel to pass? Not sure... The jetting issues in your videos are not the result of a pilot jet -to- needle combo error. Yeah, if you put a fatter needle in you might need to drop 1 on the pilot and vice versa, to improve transitional operability, but dropping from the 50s to the 30s on the pilot ain't right.

Look at this chart. Lesson: There's only a few pilot jets that can work with ANY combo of needle and main jets to keep the air screw near 1.5 turns at a closed-throttle idle as the fueling circuits are not related at idle... If that is not your case, you have something wrong, somewhere...

Keihin-PWK-Jetting-vs-TPS-chart_zpsf1d23

lol... not quite. Obviously if i stated the DGN required a 55 to run anything below a 55 that would be impossible with the DGN.

To clarify I tried different combinations ranging from a 55/DGN to a 35/DGK.

carb is fine, intake is fine, engine holds 8 psi with no change for 10minutes.

This is a 52/DGN ...embarrassingly LEAN

52/DGL (can you hear the slight lean bog)

38/DGL (could make go from too rich to start to lean bog off the pilot in about 1/8 turn on the AS)

all of those started without the choke cold and needed to be held wide open hot.

EDIT.

looked over my notes. I was running a 52 not a 55 in the first 2 vids.

Edited by Eddie8v
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I hear what you're saying, but your reasoning implies that the straight diameter of the needle has some fueling input on engine idle and closed-throttle operation, such as starting with the throttle tube closed or idling the bike, BUT it does not. The straight diameter doesn't come into play until you crack the throttle a bit and has VERY little, to no, effect on idle... So, I still feel that you have something amiss in your carb and are band-aid fixing it with jetting changes. I might assume the carb is older and worn a bit? Internal air/fuel leak somewhere? Float needle and seat set are not sealing, allowing extra fuel to pass? Not sure... The jetting issues in your videos are not the result of a pilot jet -to- needle combo error. Yeah, if you put a fatter needle in you might need to drop 1 on the pilot and vice versa, to improve transitional operability, but dropping from the 50s to the 30s on the pilot ain't right.

Look at this chart. Lesson: There's only a few pilot jets that can work with ANY combo of needle and main jets to keep the air screw near 1.5 turns at a closed-throttle idle as the fueling circuits are not related at idle... If that is not your case, you have something wrong, somewhere...

Keihin-PWK-Jetting-vs-TPS-chart_zpsf1d23

 

 

No, Im saying the pilot and A/S have an effect on the the needle straight diameter. a 52p is horribly rich on my bike but if you can get it started (by leaning it out with a open throttle) it will run and idleYou can also mistakenly cover up a lean needle (diameter) by cranking the idle screw so far in you are in the taper....

 

My bike wants a 35-38 pilot (depending on temp) to cleanly start with no throttle. lots of people insist teh cr5 needs a cracked throttle to start.. that is just poor jetting.

 

With my bike a 38p & DGL its still just barely lean on the straight diameter, you can compensate by 1 running a richer pilot so its covering up the lean needle or run the A/S all the way in again to mask the real issue (the lean needle.) You still need to crack the throttle to start and dont need the choke when cold..

 

Richen up the needle, lean out the pilot you get a smooth transition off the pilot and easy starting (no full throttle).

 

 

 

I'm not saying there are multiple correct pilots, i'm saying you can make shit run in a lot of different ways. all of those "make shit run" options have issues with incorrect carburation.

 

as for the 35/38 pilot, its not that uncommon (just about every Australian on the cr5 forum is running something similar and finds the DGN far to lean)

Edited by jar944
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jar944, at least you keep notes and are able to post video clips of your efforts, i respect that a lot. I seem to remember that you run a ktm sort body carb? what slide are you running? then it comes to mind you are not running a stock motor reeds or pipe.

I have 3 cr500 bikes with pwk carbs and know first hand their are some big differences between carb setup's on similar bikes , I watch with great intrest what works on other's bikes and you know what? I I never seen eddiev8 post any clips of his cr500 runing

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No, Im saying the pilot and A/S have an effect on the the needle straight diameter. a 52p is horribly rich on my bike but if you can get it started (by leaning it out with a open throttle) it will run and idle

You can also mistakenly cover up a lean needle (diameter) by cranking the idle screw so far in you are in the taper....

. You're not making sense at all. If your bike runs ok, I guess that's all that matters!
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jar944, at least you keep notes and are able to post video clips of your efforts, i respect that a lot. I seem to remember that you run a ktm sort body carb? what slide are you running? then it comes to mind you are not running a stock motor reeds or pipe.

I have 3 cr500 bikes with pwk carbs and know first hand their are some big differences between carb setup's on similar bikes , I watch with great intrest what works on other's bikes and you know what? I I never seen eddiev8 post any clips of his cr500 runing

Too busy working on bikes & riding to take videos of bikes running. Not sure what a video proves over words in this matter, really. I am talking about pilot jet vs idle and closed-throttle operation, not off-idle operability like his riding videos show. He's having to screw with jetting to overcome some carb operability issues, IMO. Do you run a 38 pilot in your CR500 bikes? If you have 3 x CR500 with similar/same engine configs, the jetting in all 3 PWK should be the same. If not, carb wear and/or external issues are present. Edited by Eddie8v
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Too busy working on bikes & riding to take videos of bikes running. Not sure what a video proves over words in this matter, really. I am talking about pilot jet vs idle and closed-throttle operation, not off-idle operability like his riding videos show. He's having to screw with jetting to overcome some carb operability issues, IMO. Do you run a 38 pilot in your CR500 bikes? If you have 3 x CR500 with similar/same engine configs, the jetting in all 3 PWK should be the same. If not, carb wear and/or external issues are present.

The 38 is not rare on a 39.5 pwk. 42-45 would be most common. Go to the cr5 site and post that a 55 is correct.. And yes I'm aware sh delivers them with a 55.

Can you start your cr5 55p without touching the throttle?

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I would bet jar944 has tried various float settings just to confirm ,

I ran around like a chicken listening to people tell me what was correct. Once I listened to the bike it worked out.

And yes its a pwk from a KTM 144. #6 slide (can't remember if it has the notch or not)

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Thanks for the replys and argue abouting but hey what is the trick to starting this beast my buddy can start it everytimr and i find my self kicking for 5 minutes its really annoying I'll add he grew up on 500s though

Press the kicker until the piston is just past top dead center, then bring the kicker back up and kick completely through the stroke. It also sometimes helps to give it a couple slow priming kicks first if its cold.

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