i need a lesson in jetting
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This exposes how ignorant I am when it comes to understanding how carbs work. I thought I was kinda on the right track. Anybody know of a good tutorial on cv carbs and how they operate? I would like to understand so I can solve more problems on my own, rather than trouble everyone with stupid questions. Thanks
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Tweety, gotta say, you are a lifesaver. You know all the stuff that leaves me scratchin' my head. I do have one question however. I pulled my plugs. Front was black, rear white. How did I get there? Did that occur during the sync? ? Or normal riding with the wrong setup? This was before today's adjustments. I think I'[m good now. I will post dyno graphs tomorrow.
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I wouldn't say I "know" all that stuff... Some I know, some I'm still reading and learning about... I do have a decent memory though, so I usually soak up a lot of uneccessary stuff, and some of it turns out to be usefull later on...
I doubt the sync is enough to get you different plug colours... Se what happens after a dyno and some running around...
I doubt the sync is enough to get you different plug colours... Se what happens after a dyno and some running around...
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If the plugs could look like this after a total of approx 5 minutes total of sporardic starts and rough running, supposedly on one carb, then this could explain. Because we had the carbs synced and everything was runnung smoothly and then decided to bend the tab back on the sync adjuster to better align the set screw(earlier bent by a snake tool during adjustment). This is when all hell broke loose and before we got it running smoothly again, we replaced the plugs(front fouled, rear leaned out). After we bent the tab back to straight we didn't have enough adjustment to get it to sync, so we had to bend it back the other way a little. The point is that the engine was loping radically for a while right before we removed the plugs.
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yeah they are set the same. Like i said, it was running on one cylinder for a bit. Sounded terrible, after we bent the sync adjuster. It was so bad i thought maybe it was a coil. Anyway, i would be surprised if the plugs could look like this now because it's running so smoothly. I believe he was on the dyno today if he went there. so we should know soon.
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yeah they are set the same. Like i said, it was running on one cylinder for a bit. Sounded terrible, after we bent the sync adjuster. It was so bad i thought maybe it was a coil. Anyway, i would be surprised if the plugs could look like this now because it's running so smoothly. I believe he was on the dyno today if he went there. so we should know soon.
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From: altoona, pa
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Ok guys. Here are the latest dyno graphs. As can be seen in the comparison graph, I got rid of much of the richness in the mid and upper range, but got slightly leaner at the very bottom. The dyno tech said that is about as close as I will get it. When I asked him about the lean spot he said it was of no importance. He went on to say that lean spot was produced at full throttle at 3k rpm and no one rides like that. I see his point, but is he right, or just tired of giving me free pulls on the dyno? Haha. As can be seen, it's a little leaner in that area on all the graphs, but it seems so miniscule, especially when you look at how much of that richness I got rid of. Like I said before, the bike feels fantastic, but if you guys think I need some tweaks let me know. Thanks all.
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Ok guys. Here are the latest dyno graphs. As can be seen in the comparison graph, I got rid of much of the richness in the mid and upper range, but got slightly leaner at the very bottom. The dyno tech said that is about as close as I will get it. When I asked him about the lean spot he said it was of no importance. He went on to say that lean spot was produced at full throttle at 3k rpm and no one rides like that. I see his point, but is he right, or just tired of giving me free pulls on the dyno? Haha. As can be seen, it's a little leaner in that area on all the graphs, but it seems so miniscule, especially when you look at how much of that richness I got rid of. Like I said before, the bike feels fantastic, but if you guys think I need some tweaks let me know. Thanks all.
And yeah, he's mostly right about the "you don't ride that way"... I very rarely goe to WOT at 3k... I mostly roll on a bit more subtle since I prefer to be on top of the bike, not the other way around... But on a V2 vs IL4 note... But yeah, an IL4 guy won't roll on to WOT at 3k because that will only cause his bike to sputter... Not sit on it's **** like a VTR does...
I still think it's on the rich side in the middle, but definetly getting there...
It doesn't need tweaks... But I'd probably make a few more attempts...
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Thanks Tweety. What should I change? I know from expeirence that if I go down on the needles, I will be too lean, so that limits what I can change. Maybe 50 pilots and take mixture screws out to maybe 2.75 or 3? My reasoning is that with the bigger pilots I could get away with dropping the needles to 3rd from top. Oh and just a refresher, my setup is as follows
175/180 mains
48 pilots
needles: 4th from top
mixture screws: 2.25 out
OEM filter
Thanks
175/180 mains
48 pilots
needles: 4th from top
mixture screws: 2.25 out
OEM filter
Thanks
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SuperSport
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From: NY State
IIRC you tried 2.5 turns out and it was too much - correct. If that is the case then 50pj would be too much as well. Did you try clip 5?
I do not have easy access to a dyno, my butt is my dyno, so at this point I would be out riding with a smile on my face, and maybe my butt too
JB
I do not have easy access to a dyno, my butt is my dyno, so at this point I would be out riding with a smile on my face, and maybe my butt too
JB
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Superstock
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I'd leave well enough alone. You never mentioned (that I saw) your elevation... You've been chasing your tail a bit, and the dyno operator is right...it's pretty darned good. Remember that a CV carb is a compromise at best...your needles are moving with the slides as dictated by intake vacuum. Not all needle tapers are ideal, and at cruise you are running mostly on idle circuit plus a certain percentage of metered main (which is what the needle is doing). VTR's are happiest a scosche rich. I have chased my tail and even half clip movements on my factorypro kit can really change things a lot. I live in Seattle at sea-level, but when I take long road trips into the mountains, I am always stinky rich there. You readjust needles for that, and suddenly you have lean surges at cruise...it's a crap shoot.
This is the kind of thing that makes me strongly consider flo-commander. When I take my ride this summer down the California coast and up into the mountains, I may do 6-7k feet of elevation change in a few hours...when really the bike is only happy at ONE elevation (the one you jet it for).
Tune for RIDEABILITY rather than a magic dotted red line on the dyno sheet. You were getting FANTASTIC mileage out of that thing before and said your were pretty happy with the way it ran. That would be enough for me
-R
This is the kind of thing that makes me strongly consider flo-commander. When I take my ride this summer down the California coast and up into the mountains, I may do 6-7k feet of elevation change in a few hours...when really the bike is only happy at ONE elevation (the one you jet it for).
Tune for RIDEABILITY rather than a magic dotted red line on the dyno sheet. You were getting FANTASTIC mileage out of that thing before and said your were pretty happy with the way it ran. That would be enough for me
-R
Out of my mind, back in 5
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From: Skurup, Sweden
Thanks Tweety. What should I change? I know from expeirence that if I go down on the needles, I will be too lean, so that limits what I can change. Maybe 50 pilots and take mixture screws out to maybe 2.75 or 3? My reasoning is that with the bigger pilots I could get away with dropping the needles to 3rd from top. Oh and just a refresher, my setup is as follows
175/180 mains
48 pilots
needles: 4th from top
mixture screws: 2.25 out
OEM filter
Thanks
175/180 mains
48 pilots
needles: 4th from top
mixture screws: 2.25 out
OEM filter
Thanks
Experience doesn't count unless it's been on the dyno that exact way...I agree with residentg... Possibly try the needle one clip setting in each direction... The thing is, if you swap that, you don't even need a dyno run to put it back to the way it is now... You know how to do all that... Right?
But the easiest thing to do, that you can actually do between runs on a dyno if you have the needed tool is to try 2 turns, 2.25 turns, 2,5 turns and see what the results are... Adding a quarter of a turn to the mixture screws is a 30 second job if you have the tools and have done it before... Go get yourself an angle head bits screwdriver...
wyldryce has a valid point, but he's probably missed the bit about free dyno runs, I would most definetly do the mixture screw experiment...
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Sorry... Experience doesn't count unless it's been on the dyno that exact way...
I agree with residentg... Possibly try the needle one clip setting in each direction... The thing is, if you swap that, you don't even need a dyno run to put it back to the way it is now... You know how to do all that... Right?
Experience doesn't count unless it's been on the dyno that exact way...I agree with residentg... Possibly try the needle one clip setting in each direction... The thing is, if you swap that, you don't even need a dyno run to put it back to the way it is now... You know how to do all that... Right?
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Superstock
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I didn't miss the point about free dyno runs, but I suspect that "free" doesn't really mean perpetual 
. I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it.
Again, I am definitely curious about his elevation, as I know it to make a HUGE difference on my bike. In general, I'm a fan of carbs on bikes, as I liken it to an Analog vs. Digital experience (I'm also a musician and prefer recording to 2" tape than Protools, but the world moves on, right? ) but where fuel injection really has it best is in it's ability to compensate, be it for humidity, elevation, temp etc, and wring out proper mileage from an engine. Overall, I've found drivability on most carbed bikes, once warmed up and jetted properly, to be far more forgiving and desirable that injected. My TL1000s was a nightmare that way... And my Dad's 07 FJR which I just broke in new tires on last night, was hard to be smooth on too. Of course, if we just turbo the damn thing, the bike won't give a crap about elevation
Tweety, one other question...as you can see, I have been absent from this forum in eons (career evaporated, been in nursing school and having a kid will do that), but can you comment on whether you think the velocity stacks you all had made up did anything to improve mileage in any appreciable way?
Sorry...not trying to hijack...
-R
. I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it. Again, I am definitely curious about his elevation, as I know it to make a HUGE difference on my bike. In general, I'm a fan of carbs on bikes, as I liken it to an Analog vs. Digital experience (I'm also a musician and prefer recording to 2" tape than Protools, but the world moves on, right?
) but where fuel injection really has it best is in it's ability to compensate, be it for humidity, elevation, temp etc, and wring out proper mileage from an engine. Overall, I've found drivability on most carbed bikes, once warmed up and jetted properly, to be far more forgiving and desirable that injected. My TL1000s was a nightmare that way... And my Dad's 07 FJR which I just broke in new tires on last night, was hard to be smooth on too. Of course, if we just turbo the damn thing, the bike won't give a crap about elevation Tweety, one other question...as you can see, I have been absent from this forum in eons (career evaporated, been in nursing school and having a kid will do that), but can you comment on whether you think the velocity stacks you all had made up did anything to improve mileage in any appreciable way?
Sorry...not trying to hijack...
-R
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I didn't miss the point about free dyno runs, but I suspect that "free" doesn't really mean perpetual . I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it.
. I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it.
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Wyldryce. Elevation where I live is 2200 feet, give or take 100. Seems to run great. As far as mileage. With the current setup, i rode 150 miles each way yesterday and on the way there I got 42 mpg and 44 on the way back. It was all highway. Everyday riding I usually get no higher than 38. If I ride agressively, considerably less.
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Wyldryce, I must say you have me intrigued with the flo commander. Checked out the website and perhaps its worth a try someday. I especialy like the claim of easier sychcronization. Mine has been somewhat difficult.
Out of my mind, back in 5
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I didn't miss the point about free dyno runs, but I suspect that "free" doesn't really mean perpetual . I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it.
Again, I am definitely curious about his elevation, as I know it to make a HUGE difference on my bike. In general, I'm a fan of carbs on bikes, as I liken it to an Analog vs. Digital experience (I'm also a musician and prefer recording to 2" tape than Protools, but the world moves on, right? ) but where fuel injection really has it best is in it's ability to compensate, be it for humidity, elevation, temp etc, and wring out proper mileage from an engine. Overall, I've found drivability on most carbed bikes, once warmed up and jetted properly, to be far more forgiving and desirable that injected. My TL1000s was a nightmare that way... And my Dad's 07 FJR which I just broke in new tires on last night, was hard to be smooth on too. Of course, if we just turbo the damn thing, the bike won't give a crap about elevation
Tweety, one other question...as you can see, I have been absent from this forum in eons (career evaporated, been in nursing school and having a kid will do that), but can you comment on whether you think the velocity stacks you all had made up did anything to improve mileage in any appreciable way?
Sorry...not trying to hijack...
-R
. I think at this point though, he's just chasing the dragon. I would kill for that kind of mileage, and maybe with 15/43 gearing and an agressive throttle hand when I go on riding trips (I'm always looking for the squggliest line on the map) I am never gonna get better than low 30's mpg, but I am definitely jealous of the people that post 39 to mid 40's mpg...almost jealous to the point that I don't necessarily believe it. I can approach 36 mpg if I am super light on the throttle and go a half clip leaner on the needles, but at any elevation at light throttle cruise, it starts getting nasty lean surges. Maybe that's a function of the full system exhaust, but it's frustrating not to be able to do better. Mine is always going to have a bit of soot on the tips of the pipes, because the bike just isn't happy otherwise. Could I improve on it if I were to chase the dragon and buy a different jet kit with different needle profiles? Perhaps, but I have no desire to dive into those carbs anymore when drivability is good and I'm otherwise happy with it. Again, I am definitely curious about his elevation, as I know it to make a HUGE difference on my bike. In general, I'm a fan of carbs on bikes, as I liken it to an Analog vs. Digital experience (I'm also a musician and prefer recording to 2" tape than Protools, but the world moves on, right?
) but where fuel injection really has it best is in it's ability to compensate, be it for humidity, elevation, temp etc, and wring out proper mileage from an engine. Overall, I've found drivability on most carbed bikes, once warmed up and jetted properly, to be far more forgiving and desirable that injected. My TL1000s was a nightmare that way... And my Dad's 07 FJR which I just broke in new tires on last night, was hard to be smooth on too. Of course, if we just turbo the damn thing, the bike won't give a crap about elevation Tweety, one other question...as you can see, I have been absent from this forum in eons (career evaporated, been in nursing school and having a kid will do that), but can you comment on whether you think the velocity stacks you all had made up did anything to improve mileage in any appreciable way?
Sorry...not trying to hijack...
-R
But also, my bike might not really be setup for mileage...
So far I have counted 3 original and untouched parts on my bike... Engine included... And I'm a sucker for punishment since I'm on the verge of building an engine that will get even less mileage, but more smileage...
Out of my mind, back in 5
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Was it difficult to install? If I were to use one, do I need to get as close to perfection as possible before installing, or can I use the flo commander to get there? If i can fatten up that bottom end, but leave the mid untouched, or get it leaner, I'd be satisfied. Tomorrow I'm gonna crank those pilot screws out, see if that helps.
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Joined: Jan 2005
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From: Nooksack WA
I've got one. Works very well for sorting out lean vs. rich issues. That being said, your carbs should be well synced before installing. It works by giving a common air source for the pilot jets. You can enrich about one jet size if I recall their website. Adjustment is through a hole in the side of the air box and only takes seconds.
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