TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: Jimbo45 on January 30, 2015, 09:28:18 PM
-
Hi folks! First post here!
A little background: I had an R when I was 18, back in 1995-1996. Loved it, but was sold when I was away at basic training. Now, 20 years later, I came into another R, by chance, through a trade with a buddy. It had been completely gone through about 8 years ago, frame powder coated, cases split powder coated, and complete rebuild, new plastics and A arms. He rode it a few years, and after an airbox issue, he parked it for 3 years, and then I got it about a month and a half ago.
I went through it, cleaning, lubing, adjusting, and put a near new 69mm top end on it, and a new Keihin PWK 38 airstiker quad vent carb, and went through all the wiring and put in a good OEM coil.
I have it running pretty well the past couple days finally. Carlos from BDT had set up the carb with a # 165 MJ (included a 162 also) and a # 52 pilot (included a 50 also). The DGH was set in the middle notch. It was way rich at idle with the #52, and would only idle when cold, even with the airscrew like 4 turns out. I went down to a #45 I had on hand, and at 2 turns out on the airscrew, it idles pretty well, but is still a bit rich, so I have a #42 coming that should put it in range.
The quick spin I did the other day, the 165 MJ seemed a big boggy (but I didn't get to ride it much at all), so I put a 160 MJ in with the 45 PJ. I rode it at speed, for the first time today. It seems to run very strong at full throttle and maybe a bit soft through mid range throttle. One thing I did notice, was after making a full throttle run through all gears, then slowing, downshifting, and turning around, when getting back on the gas, it seemed like it was bogging down, like it either was loading up, or the ignition was going flat. I think it was fuel related bogging, since it did clear up after a few seconds on the gas, and since it had been running strong at full throttle. When parking it, the cylinder wasn't overly hot, but pretty warm to the touch, and warmer than I would have guessed, since it was 34 degrees out, and I had putted it slowly, for about an eighth mile, to bring it back to the garage.
So, I guess my plan is to maybe bump the MJ back up a notch to a 162 (the heat concerns me a little), and lower the needle, and do some more testing. I know I need to do a plug chop, but I want to get it close by seat of the pants before doing that. Any thoughts on the bogging or power loss (it almost felt like I had left the gas valve off, and it was cutting out as I hit the gas) after slowing and downshifting from the open throttle run through the gears? Needle too rich cause that? I also have an inline fuel filter.... could that be restricting fuel fast enough that the bowl was to empty, until recovering?
Thanks for reading my thread, and I look forward to participating here. By patient with me.....I have been on 4 strokes for YEARS, and this two stroke thing and jetting is taking a while to come back to me.
(http://img.photobucket.com/albums/v163/jimbo45/20150113_144535_zpsktwiyayr.jpg)
-
Welcome here! Nice bike!
-
My suggestion. Tune in order.
1. Pilot
2. Needle
3. Main
If it bogs, that is typically lean. Sputters, typically rich. Definitely go back to the 52 pilot. Good starter needles are ddj and dej. Start rich and work your way lean
Best regards
-Jason
-
My suggestion. Tune in order.
1. Pilot
2. Needle
3. Main
If it bogs, that is typically lean. Sputters, typically rich. Definitely go back to the 52 pilot. Good starter needles are ddj and dej. Start rich and work your way lean
Best regards
-Jason
It won't even idle with the 52 pilot unless I crank the idle speed screw in all the way, and still barely. It is pretty close , but still a bit rich, with the 45 pilot.
I read the jetting thread stickied at the top of the forum. I have a good idea of what I need to do now, and how to tackle it.
-
I know I had a DGH needle in all 3 of my motors and I seemed to have good luck with them
-
I know I had a DGH needle in all 3 of my motors and I seemed to have good luck with them
I was told mine came with the DGH needle. I need to take it out and see if its marked. I thought it had 3 clip grooves, but it does in fact have 5.
EDIT: I was wrong, it does have the DGH needle with 5 clip grooves. I had the needle I used in my boys 250EX rebuild, that had 3 grooves, the same night I was inspecting the new carb. I was confused and thought it was the needle in my carb.
-
I was told mine came with the DGH needle. I need to take it out and see if its marked. Mine only has 3 clip positions instead of 5, is that normal?
I'm not sure if i've ever seen one with 3 clip positions. But i'm no jetting guru by any stretch of the imagination.
I don't know what the temp is in your neck of the woods, but it's 5 degrees here in Ohio, so don't forget that part of the equation. None of my bikes are jetted to idle well in this weather
-
I'm not sure if i've ever seen one with 3 clip positions. But i'm no jetting guru by any stretch of the imagination.
I don't know what the temp is in your neck of the woods, but it's 5 degrees here in Ohio, so don't forget that part of the equation. None of my bikes are jetted to idle well in this weather
Yeah, it was 34 degrees yesterday. I know it will run a bit leaner than it would in summer.
-
I was told mine came with the DGH needle. I need to take it out and see if its marked. Mine only has 3 clip positions instead of 5, is that normal?
Your carb was messed with by BDT. No the KEIHIN needle does not have 3 clip positions. They all have 5. What you were told can now be thrown out the window. Put in a DGH and start over.
-
^^:distracted:
-
So Carlos is reading this thread and told the OP he would send a new DGH if it had only 3 grooves. :rofl:
-
I like your bike and would suggest using bdts advise on there forum ,just for the sake of you getting what you paid for.Im not saying don't ask question here because that is welcome ,but as long as you are on friendly basis with carla,you will most likely get the right needle for your carb
-
It won't even idle with the 52 pilot unless I crank the idle speed screw in all the way, and still barely. It is pretty close , but still a bit rich, with the 45 pilot.
I read the jetting thread stickied at the top of the forum. I have a good idea of what I need to do now, and how to tackle it.
If you having to turn air screw in to get to idle ,that would suggest you are to lean on pilot, opening the aircrew allows more air to be mixed with fuel.So if slow jet is to rich you would need to open aircrew to lean out
-
http://www.duncanracing.com/TechCenter/KeihinCarbJetting.pdf
-
If you having to turn air screw in to get to idle ,that would suggest you are to lean on pilot, opening the aircrew allows more air to be mixed with fuel.So if slow jet is to rich you would need to open aircrew to lean out
No, I had to turn in the IDLE SPEED SCREW (or slide stop screw), all the way until the spring was compressed, to get it to idle with the 52 pilot....NOT the airscrew. With the 52 pilot, I could back the air screw all the way out and it would still be rich.
-
Thanks guys, I am going to wait until my 42 pilot arrive, and go from there.
-
No, I had to turn in the IDLE SPEED SCREW (or slide stop screw), all the way until the spring was compressed, to get it to idle with the 52 pilot....NOT the airscrew. With the 52 pilot, I could back the air screw all the way out and it would still be rich.
Sorry I misread your post .I have never seen a 38 go as small as 42 ,it would make me think the float level was too high.Good luck with this.
-
Sorry I misread your post .I have never seen a 38 go as small as 42 ,it would make me think the float level was too high.Good luck with this.
No sweat. I figured so. I may not be 100% with my terminology quite yet either. :shame:
-
Sorry I misread your post .I have never seen a 38 go as small as 42 ,it would make me think the float level was too high.Good luck with this.
Hmmm, that occurred to me too. How common would it be for a brand new PWK to come with the float adjusted wrong? I don't really want to completely take off the carb if I don't have too.....it was kind of a pain to get in there properly. My intake system is fairly restrictive....stock air box, snorkle block off, outerwears box cover, and well oiled (Belray) Uni filter. It seems guys with the open UNI's and K&N's typically can run much bigger pilots from what I have been reading.
-
I am an idiot. I need to correct my posts. Carlos did send the correct needle. I was wrong, it does have the DGH needle with 5 clip grooves. I had the needle that I used in my boys 250EX rebuild in mind, that had 3 grooves, the same night I was inspecting the new PWK carb. I was confused and thought it was the needle in my carb. I need to get more sleep sometimes. :confusion:
-
If I could remember every jet or needle I put in each of my 6 bikes I proly would be a genius. Good luck with jetting. I would proly have to get someone else to ride my bike if I could not figure it out. You should not have to adjust your float level, but sometimes those can get jarred around in shipping. If you have the carb off you might want to check.
-
If I could remember every jet or needle I put in each of my 6 bikes I proly would be a genius. Good luck with jetting. I would proly have to get someone else to ride my bike if I could not figure it out. You should not have to adjust your float level, but sometimes those can get jarred around in shipping. If you have the carb off you might want to check.
Thanks. I will get it sorted out. It is pretty close, I am just picky, and for sure don't want to run lean and do damage. I am pretty good mechanically, and have jetted several 4 strokes over the years. I will get the hang of the two strokes. They are just too much fun! The power band kick takes some getting used to for me, when trying to feel the pull and listen to the sound, at different throttle settings. I think I will be able to nail it down on the next outing. The only thing that baffles me, was the power loss and boggy feeling it had after I slowed from the long full throttle run through the gears. I don't thing it was starving for fuel, since it ran strong all the way when I was on the gas. I tend to think it was loading up, after coasting a bit, maybe due to the idle circuit being rich still. I dunno, I never dealt with that on a 4 stroke. Or, I guess it could be electrical. I did put a known (I tested it) OEM coil and a new 5ohm boot, so maybe the CDI or stator is acting up. But then again, I would think one of those would show some issues when on the gas at high RPM if they were the cause. I will fine tune the pilot and see if it does it again. It sure was fun to ride, though, and I had forgotten how fast these things are! Been almost 20 years since I was on one!
-
The only thing that baffles me, was the power loss and boggy feeling it had after I slowed from the long full throttle run through the gears.
2 strokes are pretty much instantaneous in throttle response. Sounds like its too rich in the midrange. Lots of us run the clip up a notch from the middle setting to get the needle a little leaner. If you run the clip up at the top then it might require a leaner needle to get where everything works good.
-
I had forgotten to update the thread on this side.
I put in a #42 pilot, and got the idle circuit pretty good at about 2.5 turns out IIRC. I had also raised the clip to the second notch to lean it out a bit, and raised the main a notch to a #162.
The idle is strong now, and on full throttle, it didn't bog, but seemed maybe a bit flatter on power than the #160, so main jet and idle circuit are looking pretty close. BUT, mid throttle range was BAD. It bogged constantly in mid throttle range, and it was so bad, I thought it was going to die out. I had to cycle between full throttle blasts and a fast idle putt, to get it back to my garage. Oops, I guess I made the needle worse by leaning it. I guess I needed to richen the DGH needle, which I wouldn't have expected, since this motor seems to like such lean idle and main settings.
I am going to richen up the clip on the needle, and see how it goes. My thinking is, if it is that out of whack (lean) with the needle in the second notch, I may need a different needle all together. Headed out in a few to see what happens.....
-
How's your reeds?
-
How's your reeds?
They looked brand new. Carbon fiber boyesen, they appear to be.
-
Ok not chipped or anything.
-
Ok not chipped or anything.
Nope. :redbull:
-
Ok not chipped or anything.
Yep, nothing like a broken reed trying to figure out whats wrong.
-
Progress! I put the needle clip on the lowest (fifth) notch, as rich is the DGH needle would go, and took it for a short spin. It runs much better in the mid throttle range, no more bogging and flaming out, in the mid throttle range! It is totally rideable now, but It does feel just a bit flat arond mid throttle, most noticeable at about quarter throttle, so I'm thinking I could go even a bit richer on the needle. This sort of boggles my mind, since the pilot needs to be about a number 40 and only using a 162 main jet (which are very close to being perfect). My next plan is to shim up the DGH needle with some stainless number 4 washers, the distance of another clip position or two. That will tell me how rich I need to go to be too rich. And from there I guess try to figure out a better needle that I can run on the middle notch, so I have some adjustability. Once I get the needle dialed, I will do some plug chops to fine tune the main (but it runs strong now). Thanks for the continuing help guys!
-
A brand new prejetted carb should not need all this work to run proper,a 40 sj is crazy .something else is wrong
-
A brand new prejetted carb should not need all this work to run proper,a 40 sj is crazy .something else is wrong
I know, right!? But, I can't imagine what else could be wrong.......
-
They didn't happen to modify the fuel circuits in the carb did they?
-
I know, right!? But, I can't imagine what else could be wrong.......
reeds have already been mentioned and you said they were good.My next guess would be bad stator and Im only drawing from my own experience .had a friend torch a brand new piston from a bad stator,he kept leaning it out to get it to run right and it ran right for a few second.If you had one you could borrow ,it would be nice.
-
They didn't happen to modify the fuel circuits in the carb did they?
I don't think so. Nothing like that was mentioned, anyway.
-
reeds have already been mentioned and you said they were good.My next guess would be bad stator and Im only drawing from my own experience .had a friend torch a brand new piston from a bad stator,he kept leaning it out to get it to run right and it ran right for a few second.If you had one you could borrow ,it would be nice.
But it runs so solid, I can't imagine the stator is bad. Starts right up everytime I try, like the 2nd or 3rd kick on choke, and runs and idles strong. WOT acceleration is very strong too. The stator is a ricky stator, with not a whole lot of time on it.
I have got it in the ballpark now, it just is odd that the idle and main circuits need to be at relatively lean settings, when the needle likes to be at a really fat setting, compared to what I am seeing others run. I don't get it.
The small pilot doesn't really surprise me so much, since I am not running a hi flow open airfilter. I have the stock airbox covered with an outerwears box cover (probably is kinda restrictive, maybe as much as just running the lid on and a snorkle), and a fairly heavily oiled uni filter with belray oil. If I were running an open element K&N, like some guys, I suspect a pilot closer a 50 would be needed. What is wierd with the pilot, is that the air screw is not easy to find a sweet spot. I start at 1.5 out, and back out until the rpms quit rising, and that is where it runs best, but if I cotinue another turn or so, it really doesn't start to slow much from a lean condition. It could be that the particular sweet spot is at about 2.5 turns out with the 42 pilot. I will put the 40 pilot in, and see if it shows a more definite sweet spot, at around 1.5 turns out, hopefully.
-
They didn't happen to modify the fuel circuits in the carb did they?
Im pretty sure Carla buys them from sudco prejetted and marks them up ,who knows though ,for a while there he was selling carb towers to anyone that had any kind of carb problem,until he ran out of stock
-
But it runs so solid, I can't imagine the stator is bad. Starts right up everytime I try, like the 2nd or 3rd kick on choke, and runs and idles strong. WOT acceleration is very strong too. The stator is a ricky stator, with not a whole lot of time on it.
I have got it in the ballpark now, it just is odd that the idle and main circuits need to be at relatively lean settings, when the needle likes to be at a really fat setting, compared to what I am seeing others run. I don't get it.
The small pilot doesn't really surprise me so much, since I am not running a hi flow open airfilter. I have the stock airbox covered with an outerwears box cover (probably is kinda restrictive, maybe as much as just running the lid on and a snorkle), and a fairly heavily oiled uni filter with belray oil. If I were running an open element K&N, like some guys, I suspect a pilot closer a 50 would be needed. What is wierd with the pilot, is that the air screw is not easy to find a sweet spot. I start at 1.5 out, and back out until the rpms quit rising, and that is where it runs best, but if I cotinue another turn or so, it really doesn't start to slow much from a lean condition. It could be that the particular sweet spot is at about 2.5 turns out with the 42 pilot. I will put the 40 pilot in, and see if it shows a more definite sweet spot, at around 1.5 turns out, hopefully.
air screw should only be opened exactly at the point were the highest idle is found,so that requires going past that point and returning to it,sounds like that's what you are doing
-
air screw should only be opened exactly at the point were the highest idle is found,so that requires going past that point and returning to it,sounds like that's what you are doing
Yeah, that is what I am doing. I guess I am comparing it to the fuel screw on 4 strokes, which I have much experience. On those, the fuel screw is very picky, one way or the other. An eight turn to far in, engine slows, and eighth turn too far out, it slows. On this R, I can back out the airscrew to a point where the rpm is the highest, and then back it another turn farther, without the engine rpm changing. But yes, I am putting it back to a richer setting, where the idle just begins to slow a bit from the highest idle.
-
................. My next plan is to shim up the DGH needle with some stainless number 4 washers, the distance of another clip position or two.
Be careful, raising the needle like this may cause the needle to pull out of the needle jet at full throttle causing the throttle to stick wide open!!!!!!!!!!!!!!!!!!
A DCH in the top clip position will give you the same mixture vs throttle position as the DGH in the bottom position you are now using.
A DEG in the middle clip position will be a little richer in the 0 to about 1/2 throttle position and the same as the DGH in the bottom position from about 1/2 full throttle position.
You need to invest in a hand full of different needles so that you can make changes and learn how these carbs really work. This is the only way you are going to learn how to tune these carbs. There are over 125 needles that fit this carburetor.
I would recommend that you put these needles in your tuning kit.
DDE, DEF, DEG, DEJ, DEK,
If one of these needles does not make your engine run correctly you probably have other problems with your basic engine package.
-
Be careful, raising the needle like this may cause the needle to pull out of the needle jet at full throttle causing the throttle to stick wide open!!!!!!!!!!!!!!!!!!
A DCH in the top clip position will give you the same mixture vs throttle position as the DGH in the bottom position you are now using.
A DEG in the middle clip position will be a little richer in the 0 to about 1/2 throttle position and the same as the DGH in the bottom position from about 1/2 full throttle position.
You need to invest in a hand full of different needles so that you can make changes and learn how these carbs really work. This is the only way you are going to learn how to tune these carbs. There are over 125 needles that fit this carburetor.
I would recommend that you put these needles in your tuning kit.
DDE, DEF, DEG, DEJ, DEK,
If one of these needles does not make your engine run correctly you probably have other problems with your basic engine package.
Jerry, have you ever had to use a 40 pilot in a 38 a/s
-
I do not recall using a 40 but I have used a lot of 45s and 48s. To make the engine idle correctly and not have an off idle lean hesitation when using pilots in the mid to low 40s, you may need to use a richer slide and or needle that has a smaller diameter where the needle is a constant diameter before the taper starts.
Most guys do not want to spend the money for different slides and needles so they usually end up having to use a pilot that is in the mid to upper 50s.
Having to use a very small pilot to make the engine idle when using some popular needles like a DGH or DEJ may be a sign that your needle jet is worn and letting a lot more fuel flow between the needle and needle jet at closed throttle than a new carb would do with the same needles.
-
Be careful, raising the needle like this may cause the needle to pull out of the needle jet at full throttle causing the throttle to stick wide open!!!!!!!!!!!!!!!!!!
A DCH in the top clip position will give you the same mixture vs throttle position as the DGH in the bottom position you are now using.
A DEG in the middle clip position will be a little richer in the 0 to about 1/2 throttle position and the same as the DGH in the bottom position from about 1/2 full throttle position.
You need to invest in a hand full of different needles so that you can make changes and learn how these carbs really work. This is the only way you are going to learn how to tune these carbs. There are over 125 needles that fit this carburetor.
I would recommend that you put these needles in your tuning kit.
DDE, DEF, DEG, DEJ, DEK,
If one of these needles does not make your engine run correctly you probably have other problems with your basic engine package.
Excellent post! Thank you for the help! I know I have a lot of learning to do, but i will get there!
-
Update:
So I shimmed up the DGH needle with two washers, the distance of what would be a 6th notch, to richen it futher. I bogged a lot from a rich condition, from 1/4 to 3/4 throttle, and the 162 main even seemed to rich bog a bit with this setting.
So, knowing that the DGH needle had a slight lean bog in the middle position previously, and ran good, but a bit flat at the bottom 5th position, I tried the 4th position, which I hadn't tried before. Took it for a spin, and this seems to be the sweet spot! It ran like a raped ape, and the needle seemed about perfect there! Maybe the 1/8th to 3/8th throttle position seemed a touch lean, but the rest felt great! The 162 main was a bit rich but rideable.
So, I am getting there. If I could find a needle, that would be a touch richer in the 1/4 throttle area than the DGH, and the entire needle a notch shorter than the DGH, so I could run in the middle notch instead of the 4th notch, I think I would be dialed in! Any needle suggestions for this situation?
Thanks for all the help guys, this is exciting, to finally get this bike ready to ride!
Got my rear Hipers that came with it installed too!
(http://img.photobucket.com/albums/v163/jimbo45/20150210_145113_zpsscrflbiw.jpg)
-
I do not recall using a 40 but I have used a lot of 45s and 48s. To make the engine idle correctly and not have an off idle lean hesitation when using pilots in the mid to low 40s, you may need to use a richer slide and or needle that has a smaller diameter where the needle is a constant diameter before the taper starts.
Most guys do not want to spend the money for different slides and needles so they usually end up having to use a pilot that is in the mid to upper 50s.
Having to use a very small pilot to make the engine idle when using some popular needles like a DGH or DEJ may be a sign that your needle jet is worn and letting a lot more fuel flow between the needle and needle jet at closed throttle than a new carb would do with the same needles.
Thanks,I always like hearing your comments
-
From the sounds of it Jerry said a deg needle would be what you're looking for.
-
Be careful, raising the needle like this may cause the needle to pull out of the needle jet at full throttle causing the throttle to stick wide open!!!!!!!!!!!!!!!!!!
A DCH in the top clip position will give you the same mixture vs throttle position as the DGH in the bottom position you are now using.
A DEG in the middle clip position will be a little richer in the 0 to about 1/2 throttle position and the same as the DGH in the bottom position from about 1/2 full throttle position.
You need to invest in a hand full of different needles so that you can make changes and learn how these carbs really work. This is the only way you are going to learn how to tune these carbs. There are over 125 needles that fit this carburetor.
I would recommend that you put these needles in your tuning kit.
DDE, DEF, DEG, DEJ, DEK,
If one of these needles does not make your engine run correctly you probably have other problems with your basic engine package.
Thanks for the help Jerry! You know your jets!
It appears the sweet spot for the DGH needle in this cold weather, is the 4th notch (which is good, since I will probably need to raise it to the middle notch in summer anyway), as far as half and 3/4 throttle go. Say, I wanted a needle to run the same in the 4th clip on a needle, but the next step richer, around 1/4 throttle? Like an identical needle, only fatter in the lower third of the throttle? I need one with the next step longer straight area at the top of the needle, correct? Which one would that be? I am thinking a DGG? I am afraid the DEG might be too much, because I like the way the DGH runs in the upper half of throttle. The charts are great, but greek to a newb like me....too many letters and numbers. LOL. THanks for all the help guys, and sorry to be such a newb, but I about have this carb set!
Edit: I just ordered DGG and DEG needles to try!
-
A little update.....
I installed the DGG in the 4th notch, and also the #40 pilot tuned pretty clean at 1.25 to 1.5 turns out. A brief test the other seemed to indicate I may have got it right finally! This stupid 9 degree weather is keeping me from doing more testing though.
Thanks for all the help guys!