i need a lesson in jetting
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Talked to dynojet today. They put me on with their "carb engineer". Whether or not he really is, I have no idea. Anyway, he told me that because of the bend angle of the high mounts, I will always have a "flat spot" in the midrange. He suggested I go 175/180 on the mains and needles 4th from top. If I'm already lean in the mid with 180/185s and the needle on 4.5 from top, just how is this supposed to work? Going up to the 5th I could see. At any rate, I'll try it. If I don't get supberb results, those 48 pilots are going in, to hell with what dynojet says.
Last edited by steve29; Jun 12, 2010 at 12:55 PM.
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Broke down and got 48 pilots. Rather than let honda rip me off at $23 a piece, I got Keihin series 21 pilots. Do these look like the right ones? Also since I'm using larger pilots, should I drop my mains to 175/180? Thanks guys.
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As for the carb engineer, we could use one of those on retainer for the Forum.
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During my last 10 years or so teaching, I would amaze some students by getting a crappy running car to idle smoothly by just adjusting the mixture screws. Most had never seen a carburetor, let alone worked on one. And my average student was in his 30s.
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Thanks. I installed the 48s, turned pilots to 2, put needles 4th from top, and synced the carbs. Ran smooth, but felt awfully soft. Tore back in and moved needles to 3rd from top, and it feels much more snappy and responsive. No misses or surges, though I'm still getting some pops on decel. Did that before the needle position change too. I'm under the impression that if pair is removed and it pops, thats a lean condition. Am I mistaken? It sure doesn't seem lean though. Guess I'll check the plugs after I run it some more. I'm booked for as many dyno runs as i need to get it right on tuesday, so I'll know for sure then. But, how does this initial setup sound to you?
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180/185 mj
48/48 pj
3rd clip/3rd clip (Dynojet needles?)
2-turns/2-turns
K&N Filter (?)
Devil High Mounts
looks like a good base line to me.
try 2-1/2 turns out, just to see what happens
sounds like
48/48 pj
3rd clip/3rd clip (Dynojet needles?)
2-turns/2-turns
K&N Filter (?)
Devil High Mounts
looks like a good base line to me.
try 2-1/2 turns out, just to see what happens
sounds like
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Thanks for the input. Yea, cant swing that at the moment. But, since the shop set me up wrong in the first place, they are letting get the dyno runs for free until I get it right. I just have to do my own tuning. If I'm still rich, I guess I can go 175/180. Then if I end up getting a BMC, put the bigger mains back in.
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How did you disable PAIR? If you just capped the valves then sometimes they can crack and leak by, causing some popping. I had the issue for years until I sprung for blockoff plates.
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I removed the pair control valve itself and all hoses. Capped where all hoses were and flipped the reed stoppers. Might have to review your knowledge base article and do the blockoff plates. Though at this point, after riding to work, I am undoubtedly lean with current settings, so I'm guessing it's a combination of the two. Guess I'll be moving those needles back up, turning those screws back to 2.5. I'd have thought for sure I could get away with 3rd from top on the needles with those 48 pilots. Guess not. But 4th from top just felt too soft. Maybe I need to step down the mains?
Last edited by steve29; Jun 13, 2010 at 12:11 AM.
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Pardon me if I sound like an *******, but this thread is some funny assed ****.
The guy who did your dyno and exhaust analysis tells you you're running rich, but you keep complaining about being lean. Do you think the dyno guy is making **** up?
The guys at Dynojet who designed and built your jet kit tell you to go down one size on the mains, but you'd rather take advice from guys who don't have a Dynojet kit, don't know anything about the Dynojet kit, and insist you can cure a rich condition by going to larger, richer pilot jets.
Maybe I'm just an idiot whose bike fuels perfectly, but that doesn't make any sense to me. Can I make a semi scientific wild *** guess? One of these days you'll end up with 175f/180r jets, needles 5 from the top, #45 pilots and an excellent running VTR! HA HA! Flame away!
The guy who did your dyno and exhaust analysis tells you you're running rich, but you keep complaining about being lean. Do you think the dyno guy is making **** up?
The guys at Dynojet who designed and built your jet kit tell you to go down one size on the mains, but you'd rather take advice from guys who don't have a Dynojet kit, don't know anything about the Dynojet kit, and insist you can cure a rich condition by going to larger, richer pilot jets.
Maybe I'm just an idiot whose bike fuels perfectly, but that doesn't make any sense to me. Can I make a semi scientific wild *** guess? One of these days you'll end up with 175f/180r jets, needles 5 from the top, #45 pilots and an excellent running VTR! HA HA! Flame away!
Last edited by RK1; Jun 13, 2010 at 03:03 AM.
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The 45"S" pj are at the edge of acceptable as shipped with the SH. Adding anything that will increase flow will push them past adjustablity with the pilot screws. The aftermarket pipes probably did this, hense my suggestion to 48pj.
Since the filter is stock, I agree with the 175/180 as I prevoiusly stated. 180/185 would not be the end of the world either. As for the needles, anywhere from 3rd to 5th is probably correct, hard to tell from a keyboard. PJ=48 with 2 turns +- 1/2 turn.
Not much of a flame - sorry. JB
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Yeah, well. Despite your claim of being the biggest ***** on the forum, you're too eager to help and have too good a heart to make good on the boast.
I just have my doubts about the value of larger pilots mostly 'cause my bike is slip ons/OEM air filter very much like Steve's and with 175/180/needles on five/OEM pilots it fuels perfectly.
PS I don't know beans about reading the emissions gas chart, but the folks here who do seem to agree he was running slightly rich, even though he reported his bike ran fine. dropping down one size on the mains and leaving everything else where he had it would probably do the trick.
I just have my doubts about the value of larger pilots mostly 'cause my bike is slip ons/OEM air filter very much like Steve's and with 175/180/needles on five/OEM pilots it fuels perfectly.
PS I don't know beans about reading the emissions gas chart, but the folks here who do seem to agree he was running slightly rich, even though he reported his bike ran fine. dropping down one size on the mains and leaving everything else where he had it would probably do the trick.
Last edited by RK1; Jun 13, 2010 at 03:39 AM.
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Unless I interpret it incorrectly, from what I gathered from the factory pro website and from some of the forum members, you want to use bigger mains so you can avoid raising the needles to fix lean holes. I'm probably wrong on that.
After dropping the needles to 4.5 from top by using the dynojet washers (if i did that correctly) the bike feels more responsive, but like I said before I'm getting the occasional lean stumble. Got a few today. Only in first gear though. I'm just lost.
What if I went 175/180 and raised the needles back to 5th groove from top? The bike never stumbled on that needle position, but it was rich. Dropping down a half step caused some stumbles. Would the smaller main size lean the mixture enough that going back to 5th groove from top would no longer be too rich? I just can't believe a half step on the needles changed that much. It kind of seems like no matter what else i do, I need to be on the 5th from top to avoid lean stumbles. If that position was too rich with 180/185 mains, it seems like the only thing left to do is go to 175/180. I don't profess to be an expert on this, so if that sounds idiotic, please correct me.
After dropping the needles to 4.5 from top by using the dynojet washers (if i did that correctly) the bike feels more responsive, but like I said before I'm getting the occasional lean stumble. Got a few today. Only in first gear though. I'm just lost.
What if I went 175/180 and raised the needles back to 5th groove from top? The bike never stumbled on that needle position, but it was rich. Dropping down a half step caused some stumbles. Would the smaller main size lean the mixture enough that going back to 5th groove from top would no longer be too rich? I just can't believe a half step on the needles changed that much. It kind of seems like no matter what else i do, I need to be on the 5th from top to avoid lean stumbles. If that position was too rich with 180/185 mains, it seems like the only thing left to do is go to 175/180. I don't profess to be an expert on this, so if that sounds idiotic, please correct me.
And at the same time... Look at the graph for where the pilot jet is running the show... low to mid... And guess what... It's above 14 in places... Ie lean...
I'm a fan of 48 pilots... If you get things right you can get good fueling all the way... Why not try going the way the numbers tells you... Same or smaller mains, a size larger pilots and then set it up... For some stange reason I have a feeling it will even things out a bit... Feel free to disagree though...
Out of my mind, back in 5
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Pardon me if I sound like an *******, but this thread is some funny assed ****.
The guy who did your dyno and exhaust analysis tells you you're running rich, but you keep complaining about being lean. Do you think the dyno guy is making **** up?
The guys at Dynojet who designed and built your jet kit tell you to go down one size on the mains, but you'd rather take advice from guys who don't have a Dynojet kit, don't know anything about the Dynojet kit, and insist you can cure a rich condition by going to larger, richer pilot jets.
Maybe I'm just an idiot whose bike fuels perfectly, but that doesn't make any sense to me. Can I make a semi scientific wild *** guess? One of these days you'll end up with 175f/180r jets, needles 5 from the top, #45 pilots and an excellent running VTR! HA HA! Flame away!
The guy who did your dyno and exhaust analysis tells you you're running rich, but you keep complaining about being lean. Do you think the dyno guy is making **** up?
The guys at Dynojet who designed and built your jet kit tell you to go down one size on the mains, but you'd rather take advice from guys who don't have a Dynojet kit, don't know anything about the Dynojet kit, and insist you can cure a rich condition by going to larger, richer pilot jets.
Maybe I'm just an idiot whose bike fuels perfectly, but that doesn't make any sense to me. Can I make a semi scientific wild *** guess? One of these days you'll end up with 175f/180r jets, needles 5 from the top, #45 pilots and an excellent running VTR! HA HA! Flame away!
Actually I believe you are right... Sans one detail... The low end of his dynograph is "leaner" than the top... And the basic idea is to level/smooth that graph out... And once that is done move it one small step in the "leaner" direction since he is undoubtedly running rich... So down on mains and up on pilots...
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Ha to you to... Actually I believe you are right... Sans one detail... The low end of his dynograph is "leaner" than the top... And the basic idea is to level/smooth that graph out... And once that is done move it one small step in the "leaner" direction since he is undoubtedly running rich... So down on mains and up on pilots...
Actually I believe you are right... Sans one detail... The low end of his dynograph is "leaner" than the top... And the basic idea is to level/smooth that graph out... And once that is done move it one small step in the "leaner" direction since he is undoubtedly running rich... So down on mains and up on pilots...Could he solve the lean/bottom by opening up the pilot screws a quarter turn or does he really need the larger pilots? Maybe a mute point since he already bought and installed the #48s, except now he's got to keep screwing around with the pilot screws and needles to get it right.
I don't know the answer, I'm asking.
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Possibly yes... But I tend to agree with residentg's statement that the 45 pilots are marginal for the VTR in a lot of conditions... So yes it could work and it could also give you a nice headache trying to solve it...
Remember all the parts affect each other... It's like a very volotile stack of cards...
If you go larger on the pilots, you can go smaller on the mains... If you keep the pilot at 45 it could mean that the smaller mains in the balance becomes too lean in some places and that's harder to compensate for than to rich (like I said he had the basics right)... And it could also be the opposite, ie the 45 is "right"... But then you will get a pronounced rich idle and decent enough otherwise once you have it set up... It's not optimal and wastes fuel, but it isn't as bad as the other way around... In fact at that point I think many will ride it and like it just fine...
The thing is, 48's are correct 75% of the time and good enough 90% the time... 45's are right 25% and good enough 50%... Numbers are just my feelings... But they give a view of my meaning... But the downside is that yes, they can most defintely mask other things like people have mentioned... So my preferred way is to get the 48's, get the apropriorate mains and go from there, not buy a kit... It's a waste of money the way I see it... But I'm a stubborn cheapskate...
Remember all the parts affect each other... It's like a very volotile stack of cards...
If you go larger on the pilots, you can go smaller on the mains... If you keep the pilot at 45 it could mean that the smaller mains in the balance becomes too lean in some places and that's harder to compensate for than to rich (like I said he had the basics right)... And it could also be the opposite, ie the 45 is "right"... But then you will get a pronounced rich idle and decent enough otherwise once you have it set up... It's not optimal and wastes fuel, but it isn't as bad as the other way around... In fact at that point I think many will ride it and like it just fine...
The thing is, 48's are correct 75% of the time and good enough 90% the time... 45's are right 25% and good enough 50%... Numbers are just my feelings... But they give a view of my meaning... But the downside is that yes, they can most defintely mask other things like people have mentioned... So my preferred way is to get the 48's, get the apropriorate mains and go from there, not buy a kit... It's a waste of money the way I see it... But I'm a stubborn cheapskate...
Last edited by Tweety; Jun 13, 2010 at 07:26 AM.
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Well seeing as how they are the ones who fucked up the install in the first place and the sole reason I'm even making jetting changes, would you be inclined to believe everything they say? And yes, I am having lean issues--each time I attempt to correct the richness, I get lean stumbles in the midrange. I was merely hoping to find my way through this with some help from guys on here. If I understood totally what I was doing, I would'nt be here. I never worked on carbs before this bike I'm simply trying to learn. I wasn't aware that there was a "funny assed" element to a guy seeking advice on his jetting issues and trying to learn his way around a set of carbs. Nor did I realize that it would earn the contempt of other members, but I've been wrong before. Pardon me if I sound like an ******* as well.
Last edited by steve29; Jun 13, 2010 at 08:06 AM.
Out of my mind, back in 5
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Well seeing as how they are the ones who fucked up the install in the first place, would you be inclined to believe everything they say? And yes, I am having lean issues--each time I attempt to correct the richness, I get lean stumbles in the midrange. I was merely hoping to find my way through this with some help from guys on here. I never worked on carbs before this bike, I'm no expert. So, if you feel the need to laugh and tanut, whatever, I really don't care.
I also think that you are concentrating on something you actually don't know for sure... With the dynorun as a baseline, you are down to around 11 A/F in the midrange... How on earth can you be 100% certain with no other supporting evidence than your feeling sitting on the bike, that what you are experiencing is "lean stumble" if you have made the changes you describe?
It could just as easily be drowning in fuel for all we know... You can do your own variations as much as you like, nothing wrong with that... But unless you are willing to try the advice numerous people have given you without deviating from it too much, it's not really fair to keep asking questions expecting us to take you further since we have no idea what direction you and your actual A/F values are going...
Try it and if it doesn't improve on things discard it... And at that point we know more...
