Ok, it's time I asked for help
- Thread starter StinkBug
- Start date
kopcicle
antidisestablishmentarian
That's got CV's? Take a #2 phillips screwdriver, heat the tip with a torch until cherry red and plunge it into your eye. It will hurt less. Really. Bikes with CVs have airboxes. Bikes with slide needle carbs have pods. Even Mark Dobeck, former owner of Dynajet, cops to a loss of midrange using his kits.
And for the other eye heat a 3/4" drill bit chucked up in an air drill ...
I can get BS34's to almost work on the 998-1100 with one serious caveat . They will pull hard with the throttle arbitrarily pinned OR they will mix fuel cleanly at part throttle cruise . Pick one I don't know how to give you both . Mark Dobeck and I went back and forth for most of a summer getting several of my customers bikes and my 998 urban terror two wheeler running right . The customers are probably still ****ed even though I neither recommended nor supplied this serious impediment to performance . In the end I knew neither was right (thanx for the flash runs Ron !) But the one that was the best and closest to right got me the most grief . That guy thinks I'm an idiot and in ten years hasn't wasted an opportunity to say so . Funny that the last two guys to touch it asked how I was able to get it so close . The one that isn't so good , that guy thinks I'm magic . The preceding applies even more so to your stock Honda carburettors and individual filters . CV carburettors require an airbox .Anything less falls short of a compromise in a horrible , frustrating and purposefully ignorant manner .
just a partial list
various attempts at
springs
needles
needle jets with and without discharge shields
pilots
mains
main air bleed
air horns within the air filters
closer to or further away from the head
adjustable cam sprockets
different headers ....
All because in one case the owner wanted to look like all the other cool kids
and the other thought it was a pain to get the carbs in and out with the stock aribox
coincidently both of these mental midgets went from 35-36 mpg to 30-31mpg and might have gained a couple of hp on top at the expense of having me spend untold hours filling a huge hole around 4k .
The stock needles are fine for all but full on racing . Why people insist on a "jet kit" is beyond me . I had many conversations over a period of several years with Mark Dobeck about individual filters on constant velocity , diaphragm carbs . Here are the high an low points of that discussion .
Great full throttle response , great part throttle cruise , pick one . You just don't get both .
The larger the volume within the individual filter the better your result .
Finding a velocity stack that will fit over the carb and inside the filter is never a bad thing until its opening is shrouded or interfered with by the filter .
Most needles supplied with jet kits are aluminum for ease of production and not steel for durability .
Find the main air bleed/jet on the inlet to the carb . This will be a fixed brass jet that unmistakably leads to the main down well that the emulsion tube , main jet , and main discharge to the throttle bore reside in . Remember this is a fixed jet and difficult (not impossible) to change . Small diameter changes in this jet can cover the usual giant hole between idle/transfer and the beginning of the midrange .
Last but not least are the ignitors , a well known problem whatever Honda they are used on . Their failure mode spans doa to intermittent as well as high rpm sign off . This last easily confused with coil degradation .
I have no idea why the membership at large has been so patient with an attitude problem looking for a place to profess his ignorance . I'm not nearly as forgiving or tolerant of fools and ignorance . You came here looking for help and were greeted by willing and helpful suggestions from the membership . You responded with unconscionable arrogance , ignorance and abuse toward those trying to help . I leave you with four options ...
1) reinstall the stock airbox
2) find a set of VM , smoothbore, RS anything NON Constant Vacuum carburettors and retain your individual air cleaners .
3) do away with the attitude and contribute to this community
4) fuck off
~kop
btw , don't bother I won't rise to the bait . I'm done with you in all of 83 posts and don't care to read another
And for the other eye heat a 3/4" drill bit chucked up in an air drill ...
I can get BS34's to almost work on the 998-1100 with one serious caveat . They will pull hard with the throttle arbitrarily pinned OR they will mix fuel cleanly at part throttle cruise . Pick one I don't know how to give you both . Mark Dobeck and I went back and forth for most of a summer getting several of my customers bikes and my 998 urban terror two wheeler running right . The customers are probably still ****ed even though I neither recommended nor supplied this serious impediment to performance . In the end I knew neither was right (thanx for the flash runs Ron !) But the one that was the best and closest to right got me the most grief . That guy thinks I'm an idiot and in ten years hasn't wasted an opportunity to say so . Funny that the last two guys to touch it asked how I was able to get it so close . The one that isn't so good , that guy thinks I'm magic . The preceding applies even more so to your stock Honda carburettors and individual filters . CV carburettors require an airbox .Anything less falls short of a compromise in a horrible , frustrating and purposefully ignorant manner .
just a partial list
various attempts at
springs
needles
needle jets with and without discharge shields
pilots
mains
main air bleed
air horns within the air filters
closer to or further away from the head
adjustable cam sprockets
different headers ....
All because in one case the owner wanted to look like all the other cool kids
and the other thought it was a pain to get the carbs in and out with the stock aribox
coincidently both of these mental midgets went from 35-36 mpg to 30-31mpg and might have gained a couple of hp on top at the expense of having me spend untold hours filling a huge hole around 4k .
The stock needles are fine for all but full on racing . Why people insist on a "jet kit" is beyond me . I had many conversations over a period of several years with Mark Dobeck about individual filters on constant velocity , diaphragm carbs . Here are the high an low points of that discussion .
Great full throttle response , great part throttle cruise , pick one . You just don't get both .
The larger the volume within the individual filter the better your result .
Finding a velocity stack that will fit over the carb and inside the filter is never a bad thing until its opening is shrouded or interfered with by the filter .
Most needles supplied with jet kits are aluminum for ease of production and not steel for durability .
Find the main air bleed/jet on the inlet to the carb . This will be a fixed brass jet that unmistakably leads to the main down well that the emulsion tube , main jet , and main discharge to the throttle bore reside in . Remember this is a fixed jet and difficult (not impossible) to change . Small diameter changes in this jet can cover the usual giant hole between idle/transfer and the beginning of the midrange .
Last but not least are the ignitors , a well known problem whatever Honda they are used on . Their failure mode spans doa to intermittent as well as high rpm sign off . This last easily confused with coil degradation .
I have no idea why the membership at large has been so patient with an attitude problem looking for a place to profess his ignorance . I'm not nearly as forgiving or tolerant of fools and ignorance . You came here looking for help and were greeted by willing and helpful suggestions from the membership . You responded with unconscionable arrogance , ignorance and abuse toward those trying to help . I leave you with four options ...
1) reinstall the stock airbox
2) find a set of VM , smoothbore, RS anything NON Constant Vacuum carburettors and retain your individual air cleaners .
3) do away with the attitude and contribute to this community
4) fuck off
~kop
btw , don't bother I won't rise to the bait . I'm done with you in all of 83 posts and don't care to read another
StinkBug
Been Around the Block
kopcicle said:
LOL, funny I was about to thank you for such a well written and informative post until you decided to get hostile. If you had actually read what I wrote you'd see I was frustrated with just a couple of dickheads in particular, and even while being frustrated admitted that they knew more than I did and asked that they simply either help, or not help, rather than being dicks. I guess admitting ignorance, and expecting to still be treated with any kind of respect is a little much to ask of some people.
Most of the early posters to this thread were actually quite helpful, and I completely appreciated their suggestions. I didn't start getting frustrated until after I tried some of their suggestions, came back to report the findings and started getting snide responses that were basically calling me an idiot, without outright saying it. I fully admitted to not knowing what I was doing, that's why I asked the questions. To those who were actually gracious enough to help me I'll gladly say thank you very much. To those of you who think you're too good to be nice to someone who admits to not knowing something, I say go fuck yourself, or at least just dont bother wasting your time being a jerk.
I've spent many hours on the internet providing advice on the things I do know a lot about, including some topics that are repeated over and over and over again like I know these carb tuning threads are. It's actually gotten me a ton of business over the years, as well as earned me a few friends as well as a seat in a few races. I understand that you dont like answering the same shit over and over again, but nobody is forcing you to do it. The easiest thing in the world is to not click on another thread asking about carb tuning if it bothers you so much.
As for contributing here.....this is the first thread I've ever posted asking for anything. If you look through my 2 build threads on here you'll see step by step photos and descriptions of how I've done everything. It may not be much, it may not be anything revolutionary, and it may not be up to your standards, but I contribute what I know. Hell just last week a member here hit me up in one of my threads asking for info about proper welding procedures for a part he was making, which then moved to PMs. I'm happy to share the knowledge I have, its too bad some of you dont have the same attitude.
If you go to either of the DOHC 750 forums you will note that there is a notice on the front page that they will no longer discuss pod filter tuning. Also, I think your carbs are dirty because you describe having cleaned them in a fashion that did not involve a full teardown and soak.
Read back through this thread without the assumption that everyone is out to burn you and i think you'll note that you got answers pretty well in line with the data you provided. Assume everyone is out to get you and you'll find it where you look for it and your bike will still run like shit.
Read back through this thread without the assumption that everyone is out to burn you and i think you'll note that you got answers pretty well in line with the data you provided. Assume everyone is out to get you and you'll find it where you look for it and your bike will still run like shit.
mydlyfkryzis
当有疑问时踢你的敌人在生殖器上，你可以道歉后
No attitude from me, but frankness.
The only "easy" way to tune a carb properly is with a dynanometer. Otherwise it is constant plug chops and takes a long time.
You are asking for help with a complicated process. Tuning a carb properly for non-stock application is a skilled task, requiring some definite understanding of how the carbs work.
Teaching someone to diagnose carburetor issues over the internet is like teaching someone to ride a bicycle over the internet. I can give you lots of information, but ultimately, it requires your own skill and courage.
I read through all three pages of this. You have been given every step needed to resolve the issue.
I seen some things that cought my eye. You said 2 carb don't hit the idle adjustment screw. That means the carbs are out of sync. Syncing carbs is a process. You can't do it in a minute. My CB360 takes some time and it's only 2 carbs. My 750 takes a lot longer, as it is a repetitive process.
do you have vacuum gauges to really see if they are in sync? Out of sync carbs will idle terribly. Off throttle will be a problem with stumbling. I have both a 750 and a 360, and when the carbs are out of sync, they are really rough.
You can't adjust carbs with internal blockages. that was covered.
Pods are problematic as the flow into the carburetor is not laminar, and the turbulent flow messes up their response. A little roughness you will need to live with, because that's the nature of pods.
The "dickheads" gave you good advice. If you can't see past the attitude and recognize the good information, you can pay a shop to fix it, and learn that it is cheaper to put up with a little poking here, then pay someone else to fix it for you.
Also, you need the face the possibility, the reality, that you may not have the skill to fix it. There is more then nut and bolts to take off and replace. Tuning an engine is a craft, a skill. Not everyone has it. My wife can't tune a lawnmower. She does other things well. If you are really having trouble getting where you want, you need some help with the bike, from someone who is experienced and touching the bike. The internet will not teach you everything.
The only "easy" way to tune a carb properly is with a dynanometer. Otherwise it is constant plug chops and takes a long time.
You are asking for help with a complicated process. Tuning a carb properly for non-stock application is a skilled task, requiring some definite understanding of how the carbs work.
Teaching someone to diagnose carburetor issues over the internet is like teaching someone to ride a bicycle over the internet. I can give you lots of information, but ultimately, it requires your own skill and courage.
I read through all three pages of this. You have been given every step needed to resolve the issue.
I seen some things that cought my eye. You said 2 carb don't hit the idle adjustment screw. That means the carbs are out of sync. Syncing carbs is a process. You can't do it in a minute. My CB360 takes some time and it's only 2 carbs. My 750 takes a lot longer, as it is a repetitive process.
do you have vacuum gauges to really see if they are in sync? Out of sync carbs will idle terribly. Off throttle will be a problem with stumbling. I have both a 750 and a 360, and when the carbs are out of sync, they are really rough.
You can't adjust carbs with internal blockages. that was covered.
Pods are problematic as the flow into the carburetor is not laminar, and the turbulent flow messes up their response. A little roughness you will need to live with, because that's the nature of pods.
The "dickheads" gave you good advice. If you can't see past the attitude and recognize the good information, you can pay a shop to fix it, and learn that it is cheaper to put up with a little poking here, then pay someone else to fix it for you.
Also, you need the face the possibility, the reality, that you may not have the skill to fix it. There is more then nut and bolts to take off and replace. Tuning an engine is a craft, a skill. Not everyone has it. My wife can't tune a lawnmower. She does other things well. If you are really having trouble getting where you want, you need some help with the bike, from someone who is experienced and touching the bike. The internet will not teach you everything.
the real easy way today is i use a air/fuel ratio meter on my test development bikes with built in data logging
and 4 broadband o2 sensors in the exhaust go for a ride then pull the usb key and stuff it in my laptop and see
what happened then make adjustments
the dyno gives me good power and full pull data but sketchy for drive ability issues
the stock jetting on the 1980 carbs i took off my cb750 to put the mikuni setup on was 68 and 140 mains
and 4 broadband o2 sensors in the exhaust go for a ride then pull the usb key and stuff it in my laptop and see
what happened then make adjustments
the dyno gives me good power and full pull data but sketchy for drive ability issues
the stock jetting on the 1980 carbs i took off my cb750 to put the mikuni setup on was 68 and 140 mains
StinkBug
Been Around the Block
Rich Ard said:
Maybe you should try giving advice like this rather than saying "try cleaning them for real". This post was actually constructive, and respectful. The other one you came off as an arrogant prick, and I'll admit I was already a bit frustrated with the bike, and took it badly. I honestly wasn't trying to start a shit show, more pointing out that it takes the same amount of time to help someone as it does to help them while calling them an idiot. When it comes to this stuff, I probably am an idiot, but I'm trying my best to wrap my head around all the info that's here, and trying to apply it to the parts in my hands. I know a lot of the terms and parts and procedures are common knowledge around here, but I've spent my adult life building off-road trucks and desert racers, not old bikes. I can tell you how to set up a 4-link, how to tune a coil-over, how a bypass works, and how to calculate the bends in your roll cage. I cant name every piece in this carb setup though. I tried to give all the pertinent info up front, and added more that was asked. When I was given an attitude.....well I gave one back. I'm sorry, I'm human, it happens. Lets move on. Thanks for getting more constructive with your responses.
Pretty sure I found the problem. I opened up the #1 and 2 carbs last night and it does look like the pilot jet on #1 is clogged up. It's not flowing anything through to the pilot screw passage. Unfortunately it is one of the pressed in pilots, and not a screw in like I thought so it's becoming a real pain in the ass to get cleared. It's soaking in a can of Carb dip right now, and I've run about a can and a half of carb & choke cleaner through the various ports, but that one is still clogged. Am I on the right path, or is there something else I should try to get it clean?
StinkBug
Been Around the Block
mydlyfkryzis said:
I think there may have been a little misunderstanding. I didn't say 2 carbs weren't touching, I said that the main idle adjustment screw wasn't touching. The big plastic knob thing in between the middle 2 carbs that pushes on the deal the throttle cables pull on.
I sync'd the carbs with an old motion pro mercury vacuum tube deal a friend of mine gave me. 4 big long tubes with a bunch of mercury sitting in the bottom and 4 hoses going to the ports. They are all within a small fraction of each other.
I wasn't expecting anyone to be able to completely tune this thing for me over the internet, just tell me some reasons for the backfiring at idle, which they did. The bike actually runs great other than the idle. I've been riding it as is for several months now. I just finally got around to doing the sync and was a bit confused when the idle got worse and not better.
That's exactly what the guys have been saying about cleaning the carbs. Blast carb cleaner and compressed air through every drilling and passageway and compare one carb to the others. If you don't have a compressor, but a couple of cans of air for PC cleaning. They come with a tuibe that let's you get into those small passages.
Maritime
Over 10,000 Posts
What sonrier just wrote is important in syncing. Bench first with carbs on rack so you can look at the butterflies and see them all open and close at the same time, if one hits the closed position first, it will screw with the rest and your idle. Or 3 of 4 are all closing right and one is sticking open. Really hard to see that on 4 carbs on the bike with frame bits and crap in the way. I know it sucks to pull carbs off the bike, but try it on a goldwing where they are under the tank in a box of 4 instead of a line, that is fun! Good luck but I would say pulling the carbs, cleaning them again as best you can and then bench syncing them, setting to factory settings on Air turns etc., then putting them back on and starting from there, clean slate so to speak and then taking one part at a time to correct until you get it is the best course of action. ALso not sure on the 1980 CB750 but the rod that connects the butterflys on the racks may have corrosion that can hang up one or 2 of them and just a good cleaning and lubing can help a lot. My CX when I was bench syncing the carbs I (Same style CV only 2) the shaft was crusty and the choke would hang on one carb even though all the slack was off the choke cable.
SONICJK
Reminds me of...me No, I'm sure of it. I hate him
Also just a note:
If your idle screws aren't making any difference check your pods to see if get block airflow to any of the small openings in the very front of the throat on those cv carbs. Cheap pods have a lip inside that blocks flow, totally screwing your idle adjustments
If your idle screws aren't making any difference check your pods to see if get block airflow to any of the small openings in the very front of the throat on those cv carbs. Cheap pods have a lip inside that blocks flow, totally screwing your idle adjustments
K
Kamn
Guest
And if you have the means, clean them in an ultrasonic cleaner............Harbor Freight cheapy is actually a good cleaner
StinkBug
Been Around the Block
The carbs are out of the bike right now, with the one soaking in carb dip. The butterflies all appear to be very very close to each other, but I haven't actually measured their positions yet. I will before putting everything back together. Regardless they are all opening and closing together and not hanging anywhere. I'll be going through the whole syncing process again when I reassemble though.
On that topic though, I've seen a lot of mentions of bench syncing, and "the two finger method" but cant seem to find any details on this method. Anyone have a link?
Pretty sure this one just comes down to the passage between the pilot jet and the idle mixture screw being clogged. Would explain why everything is happy above idle and why adjustments to the screw didn't do anything. It wasn't getting fuel either way.
On that topic though, I've seen a lot of mentions of bench syncing, and "the two finger method" but cant seem to find any details on this method. Anyone have a link?
Pretty sure this one just comes down to the passage between the pilot jet and the idle mixture screw being clogged. Would explain why everything is happy above idle and why adjustments to the screw didn't do anything. It wasn't getting fuel either way.
