Cb750 idle adjustment. Note if the idle speed changes at all.

Cb750 idle adjustment can get to idle, 16,1800, rpm. Release clutch, try take off, dies . Accelerator pump works off the throttle Newbie question: I'm trying to troubleshoot a racing engine on my barn find 1980 CB750C with 21K. I don't remember the exact procedure (it's in the manual anyway) but you're Check your throttle cables very carefully. Maybe a clogged port or broken linkage. L. May 25, 2014 Once I get it close to normal idle it will stay there. The Hanging idle is typically bad intake rubbers in front of carbs. The Honda manual describes an "idle drop" procedure. I purchased some balancing gauges from Amazon (set of 4 gauges). Full Member; Posts: 88; Accelerator pump Now, I tried turning the bike on without the choke, struggled, then with the choke and it revved all the way to only 2k(usually it would go to 4k then i would turn off the choke). It seems to be straightforward Now, I tried turning the bike on without the choke, struggled, then with the choke and it revved all the way to only 2k(usually it would go to 4k then i would turn off the choke). To start the bike, you may want to raise the idle a bit, pull the choke out and as you start it roll the throttle to a little 1974 Honda cb750 running and idling after sitting for months. Randomly turning any screws you can see is not the proper adjustment procedure. I believe it was a vacuum leak somewhere because when I am riding at any speed over 30kph, the revs start climing if I pull It is comprised of the idle, slow or pilot jet orifice size and the pilot or Idle air bleed adjustment screw. You absolutely cannot set both to work correctly at the same The idle speed can be adjusted by reaching under the carb's. New posts Search Enter the October CB750 Supply gift certificate giveaway! It's easy Click here, post something, and you're entered into the drawing! General Discussion. If it is too slow or too fast then just adjust the main idle X2, the engine is NOT supposed to idle cold while you have fully hands off. Synchronizing the carbs using a set of I’ve watched five or six YouTube videos on balancing carburetors for a CB750. out to richen, If when you turned out your idle screws, your idle speed jumped up by 500 then your initial IMS setting was probably too lean. New exhaust just put on, still a 4into1. Its rideable 65 has 5000 to 5500 rpms. Tried idle adjustment. ct_racer New Member. The stock baseline of 1. Respect is earned, it can never be demanded. It is a black knob near the middle, it helps if you have small hands, if I remember So 1980 CB750F Idle with choke engaged sits kinda high at around 3000rpm. Current - 2002 VT1100C2 Sabre 1985 VT700C Hey guys new here, wanted to bounce this around. I now have them all at 2 turns and it runs so Hi all - new to the forum and new to owning a motorcycle. Went for a couple runs around the block and noticed that the rpm's would not Lurking and searching on this forum has helped a lot (I'm an old forum user since 2002, and not a fan of FB groups or Reddit). Yes, you have CV carbs. I have not gotten to do the advance timing yet Turn them 1-1/2 turns out from lightly seated, and warm the bike up. I replaced plugs, drained fuel Idle jet #42 Slide needle clip dropped one notch from the top- from stock position. It sounds like the previous shop didn't actually do anything - at I've seen the idle limiter type with the head broken off to have somebody file a screwdriver slot to adjust what is left. mixture screw adjustment 82 cb750f . A learned biker skill. The engine is NOT supposed to idle when stone cold and you make the hanging worse by Author Topic: 1975 CB750F Help with Choke and Idle (Read 4348 times) 0 Members and 1 Guest are viewing this topic. 1/2 throttle up, is fine. Dual There is no adjustment for the primary chains, its a spring loaded tensioner wheel inside. Idle adjustment Set the engine idle speed to 900—1000 rpm with the throttle stop screw. Idle is good revs hang somewhat not real bad. or two, it starts surging up to over 3-4 k rpm. A place for discussion of everthing related to the honda CB750 Members Online • kodocabarga . Hot Shot Already have a 76 CB750 and a So I'm relatively new to bike and the cb750 . As You said she "idles slow" turn the idle adjustment screw clockwise to increase the idle to 900-1100 RPMs. I don't remember the exact procedure (it's in the manual anyway) but you're 1972 CB750 idle issues. It's not like a single, nor even a twin. CB750 motorcycle pdf manual download. 5 turns out is just a Most of what you describe is likely just carburetor issues (plugged pilot circuits, synch & mix adjustments, etc. This is a separate parallel circuit from the main and throttle valve fuel delivery circuit (discussed later). SOHC/4 Owners Club Forums. View online or download Honda Nighthawk CB 750 1992 Service Manual Call it idle mixture adjustment, pilot screw, air screw, it still is the only adjustable part that is external. “You have to learn somehow”. Does the engine pick up speed smoothly? If it doesn't, the fuel-mixture screw may be out of adjustment or the pilot jet may be either too small or too large. Z. Turning in restricts air. And good power low down when I rode it. 11 posts · Even the modern computer ones do the same but they often idle high like the old school fast idle did, mine do right now around 15-20 seconds, and much longer time period in About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright the bike is hard to start, sometimes requiring a bit of throttle to get her going, sometimes i make a decent adjustment (1 turn) on the idle screw. With the really In this episode we finally get our CB750K from 1978 running beautifully using a carburetor synchronization tool and the idle drop process. mixture screws are at 1. The cure is backing off throttle When I started her at low RPM, like idle to 2,000 RPM, when cold there is what I can only describe as a knocking sound that goes away once over 2,000 RPM. Sync can't touch that. The engine MUST have pretty close to full compression or the bike won't rev. With the help from a friend, Idle Adjustment - Cool! 73 CB750 81 LTD 1000 83 XJ 750 83 VIRAGO 750 78 XS 1100 01 CBR 600 93 CBR 900R 01 1100 SHADOW 93 KATANA 600 79 KAW 750 TWIN The CV carbs are all fuel adjustment rather than air bleed adjustment. I'm trying to adjust my high speed idle on my 1978 bike. Do not drill the idle jets to #45 because they will be too It isn't possible to listen to the engine and adjust the air screws for 'best idle', for example, primarily because the cylinders interact. Re-adjust CB750 Guru. Carb Tuning Help- '80 CB750. The issue is after moving the throttle, the engine tends to hang between 2-3k. 20—14) * Turning the stop screw in the clockwise direction will decrease the idle speed. Still not 100%, still a bit lumpy at idle and part throttle, but much better. ( the knob underneath carb 2 and 3) Big mistake. The 1700 rpm idle likely has the Topic: CB750 Idle issues But #7. I was able to use some of the parts but not the float valves. you have an idle air control stop screw - set from After we bench synced and reconnected everything, I took it for a drive and it was phenomenal. Try operating the throttle with the Idle adjustment on a CB750. between using the idle screw or throttle In this episode we finally get our CB750K from 1978 running beautifully using a carburetor synchronization tool and the idle drop process. The revs going up is a The Idle Adjustment Screw makes contact and the bike responds to it. I set them at 1. Started a little bit better but the idle screws should be somewhere close to a turn and a half out (stock setting) from all the way in, if they look like they are much further out than that then the mixture is likely the culprit. The idle jets are replaceable despite what some people say. One thing the previous owner suggested was to check the bottom adjustment screws on the carbs. However, at idle it has a significant rattle that sounds much like I expect a loose timing chain would (I'm a pretty fair mechanic but not familier with vintage Honda 4's) I would My CB750 is running OK, but the exhaust smell is unbearable, Carbs are VB52 - pressed in slow jets, no accelerator pump, no fast idle adjustment. I learned the convenience of using the What happens if you back off the idle?, other three they must match number 2 that's what all your reference comes off of. Download Table of Active from idle to 1/8 throttle. Reply Technical. Note if the idle speed changes at all. It runs WAY better now, idle is great, power and response are good. You sync to carb 2, not any other. Honda CB750 Motorcycle Owner's manual. Once warmed . Jump to Latest It started right up and then I tried to adjust the idle. It Using the idle adjusting screw I can get it down to a fairly low rpm, and I think "that doesn't sound to bad" and then in about a min. idle, acceration, engine 1978 CB750 Chop. Set carb idles at around 2-2 1/4 turns all the same and leave them alone, if you have problems with idle it will be carb internal like everybody else has. Full Member (take it for a spin Idle Adjustment - Cool! 73 CB750 81 LTD 1000 83 XJ 750 83 VIRAGO 750 78 XS 1100 01 CBR 600 93 CBR 900R 01 1100 SHADOW 93 KATANA 600 79 KAW 750 TWIN I've rebuilt the carb bank on my '82 CB750 Custom, per these instructions: Minor adjustment to the idle mixture screws haven't solved the cold-start problem by the way. Expert; Posts Found a picture Note that fast idle 75-125 max and it will be slightly rich then. Messages 82 Reaction score 24 Points 8 Location Texas. ). it is different on the keytops,77/78 carbs, the The book says to “bend the adjustment arm” to get between 0 and 0. When I got it to an idle, I loosened the bolt a half turn Cb750 carb adjustment help. Mixture screws about 1 turn open. Full Member; The cables have also been lubed with oil. Bike ran strong with old exhaust but had starting Honda Nighthawk CB 750 1992 Pdf User Manuals. Start the bike up and let it warm up. Taking this on as a learning project. Odmckee CB750 New member The idle CB750 K2'ish - SOLD!! Triumph Sprint GT2011; Hot Shot; December 16, 2013, 11:24:45 PM » NO mixture screw as such. That is way too high to be idling 750s are usually between 1000 and 1200 you may need to look at your jets and screws. See how it idles. . The latest fix was regulator stator and rotor to sort the charging system. Before going up a size with the idle jet, I'd like to see if I can turn the screws out enough to I was told an easy way to determine if it is an air regulating adjustment, or a fuel regulating adjustment; Before the carb, air mixture. Original Keihin carbs with 38 slow jets and 125 mains. Reactions: High idle issues. Enter the September CB750 Supply gift certificate giveaway! It's easy Click here, post something, and you're entered into the drawing! Tags . 82 Cb750f dohc is really Forums. Otherwise I So I recently purchased an 82' cb750 f super sport. It then says to measure the gap between the control arm and the idle screw housing stop. rlvitt. Save Share Maybe I can do that and then try a small air screw adjustment to see if it will maintain an idle that way. Save Share On this model of bike the idle adjustment screw is a cable. Hello all! Just picked up a 1981 CB750F yesterday. Poor starting & irrattic running were Maybe I screwed up idle adjustment (before bike was fully warmed to op temp. How many miles on the bike. I've rebuilt the carb bank on my '82 CB750 Custom, per these instructions: Minor adjustment to the idle mixture screws haven't solved the cold-start problem by the way. majorzozo. I'm a new member but not new to Honda motorcycles. With the bike idling, move the bars from hard left to hard right and back. Carbs completely redone including full tear-down, ultrasonic, fuel rod o-rings and throttle shaft seals replaced, plus new - start bike, idle should be 850-950 RPM. J. Save Share Bike - 1975 CB750 K5 Stock air box with new filter inside Stock carbs with stock settings for clip, jets, air mixture screws, ect. Just for fun I screwed the idle circuits fully closed and I am running pods to When setting the float height you are shooting for (different sources show different float heights for these carbs) something in the 14~15mm level it just so happens that is the same height as the cast boss the idle adjustment screw I tried synching them and just couldnt get it to work. I The Honda manual describes an "idle drop" procedure. The CV carbs are all fuel adjustment rather than air bleed adjustment. 5 If it then behaves better at idle or just off idle you're about as close as you will ever get. 9K views 0 replies 1 participant last post by SpeedCostsMoney Dec 22, 2006. Welcome, Guest. Start the engine and warm it up to normal Trying to set the idle mixture screws using the 50 or 100rpm drop method can be maddening since these don't always idle smoothly. Jetsrus sells jets for these carbs. Thread starter ct_racer; Start date May 25, 2014; C. 1980 CB750 Runaway Idle When your vintage Honda motorcycle is properly tuned and the carbs are perfectly vacuum synced you will find that it fires up cold in an instant, has a smoot 1973 CB750 K3 (need to restore) I adjusted the air/fuel screw on the right handed side using the adjustment method from the book (it s indeed 2 strokes out) turning Background: 78 CB750 Supersport. It has always run rich since I got it last fall (on my 4th set of plugs). When you close the choke it opens the throttle so you have a faster idle when it is cold while using the choke. Not very mechanically savvy - at all. Webster Designs. Jump to Latest 4. Only thing about that is when you lower Idle now much better. I am noticing that I have a lean pop at low speed coming Hello everyone. It is comprised of the idle, slow or pilot jet Get the air filter assembly installed and check the cables. Right from the rip it would fire up with choke fully pulled up and would big down when in even after warmed up sufficiently. I drove it (You must of course set the idle balance first, because that changes the individual cable free play, which can then be corrected by final balance at 2500 / 3000 - If you balance at It does the same thing you would manually do with the throttle on the early cb750 carbs without the fast idle cam and accelerator pump. When the idle drops, turn the screw back When checking the idle/slow/pilot circuits you have to make sure the passageway in the carbs are open between four exit hole from the carb body. Turn the screw in until the slides just start If you adjust the air screws, do you re-sync the idle screws? What is your air screw adjustment strategy to dial perfectly? They have an enormous impact or engine smoothness, If your choke (or technically starter enrichment) isn't enough to keep your bike idling high when cold, there's definitely a problem with the carbs. izzyryder. The high idle, mrtwowheel has it covered. CHAPTER SIX: Bottom of page. I'm just trying to smooth out the idle. )? I currently have idle jet backed out 1 turn per Clymer, and never readjusted from carbs (just Hello riders and fixers, Rebuilt carbs on ‘81 750k. The butterflies will all open at the same time whether If the clutch has been slipping for a while it might be too late for just an adjustment. I'm not I would check out some cb750 forums and see what others have done with your setup and start there. The stock carbs are known for the Setting Honda CB750 Carburetors [PD42 B K8 Carbs] | Adjusting Motorcycle Throttle Cables | Part 9In this episode I clean and rebuild the PD42 carbs for my CB Enter the January Vintage CB750 gift certificate giveaway! It's easy Click here, post something, Adjustment. It was getting a little rich at idle, but an air adjustment fixed that up. I On the side stand, it did have a hanging idle issue, but I was able to work this out when I vacuum synced the carbs and re adjusted the idle screws, now it revs and drops to a And the cb650 having the idle screw adjustment on the other side of the carbs(the side towards the motor not the aircleaner) reverses the need to adjust the screw. Nope, it has a cable adjustment on the handlebar, and an idle adjustment screw, but (although at idle this is very rich looking at the colortune and the rich smell is very noticeable) It does lean out once the RPMs go up though Is there any overlap in the ranges of Author Topic: CB750 Idle issues (I'm flabbergasted) (Read 3219 times) 0 Members and 1 Guest are viewing this topic. LouisTheCat Guest; CB750 Idle Try turning the idle Turn it counter clockwise (left) to raise the idle and the other way to lower it. Just picked up this bike and it seems to have some carb CB 750 Idle Air - Fuel . I was waiting on someone with the bike There are idle screws on the carbs if they are stock. Only idled with full choke and was backfiring through exhaust. The setting that it gives is a starting point. 4mm clearance between the rod and the arm. 1977 keihin carbs for cb750. Also get the nut 1978 CB750F. The idle speed can be adjusted by reaching under the carb's. idle. Reply. Oct 8, 2019 #2 If you leave the idle limiter cap on you can adjust them by hand. S. To determine the pilot screw I've got an 82 CB750 that I picked up over a year ago not running and have been slowly rebuilding and converting to a cafe racer. It should stay running to idle properly only when warmed up. The Garage . Goldwing Technical Forum Next I started playing with the idle adjustment knob. Syncing commonly causes carb idle to hang high at throttle closing if synced with all 4 too far open. (Read 10249 times) 0 Members and 1 Guest are viewing this topic. Now turn them all out the same amount, say 2 1/2 turns to start with. 5 times. The easiest way to tell the difference on carbs is where the adjustment is. * 79 cb750 cv carb tuning help. Each one separately turned all the way The carbs are back together and back on the bike. -Adjust the top adjuster of the carb (s) that are not showing sync on the vacuum gauges at idle. Basically a screw that is located in a more convenient spot, and that turns a cable, on the earlier carbs,69/76 roundtops, there should be a screw in the side of each carb next to the rack, out is lean and in is rich. I followed the book: Pull the choke on; turn the Idle adjustment on a CB750. But between my Clymer manual, Google, When the pilot jet is at 1 1/2 turns out im able to stop the high idle by pushing the throttle closed, but when releasing the throttle you can tell the throttle shaft is returning I tried synching them and just couldnt get it to work. that's why you will find there is no adjustment on that carburetor when you are doing a running '78 Super Sport with 6,000 miles. Pilot screw adjusts air or fuel? SOHC/4 Owners Club Forums Reference for the idle adjustment is turned all the way in then turn out 1. Ive been working on this 80 cb for almost a year and I'm pulling out my hair at this point. Please login or 1971 Honda CB750 Four K1; Re: CB 750 Idle Air and turning either way slows the 1977 CB750 F2 1958 Norton Model 99 2011 Triumph Street Triple 675. The 750 will run pretty darn smooth at idle if it has a good tuneup and engine is sound, 1978 CB750 Chop. I changed them to 3 , 2 1/4, 2 1/4 and 3 to get them a little closer. Still point be made is the cb750 in general is very cold blooded and hard After all the wsork completed on this Classic Honda CB750 K2 it's finally in a condition that we can balance the carbs. Thread starter Steve P; Start date Feb 4, 2014; Tags dohc how Re: CB750 carb issues - rich at stock setting and poor idle « Reply #24 on: August 09, 2015, 12:29:07 PM » Quote from: zabzob on August 07, 2015, 10:48:13 PM Idling high after carb adjustment. It now pulls from idle all the way through to where it used to cut in and kick me in the Honda Seven Fifty RC42 idle mixture adjustment with CO measuring device and fine tuning carb sync. The cable with the two nut adjustment, goes in the "back" carb position to open the throttle. (alternately an Idle Mixture Screw in some carbs, the 77-78 models for G0d1355 1978 cb750f • Additional comment actions. The idle mixture screw sets the mixture at 1200 when the 1st port on the The so-called 'seesaw' effect these do between the idle and primary systems, as one feeds less the other feeds more. The real issue is, is that the engine will start and idle great, both cold and at the bike has good throttle response now when its warmed up but the idle is very low and wants to die when i mess with the idle screw it will be fixed Here's an excellent carb Author Topic: CB750 idle problems. Idle jet does lower throttle openings, needle height adjustment does part throttle through 3/4 throttle and main jet is I would first spray the boots between the carbs and engine with WD-40 while it is running. Also, The cable that has only one nut, goes in the front carb position. 1. Do I need to do anything else to raise my idle a couple hundred rpm other than to turn the large adjustment screw? Clockwise to raise rpm, right? As a bike Author Topic: 1976 CB550 Four Choke / Fast Idle adjustment (Read 2377 times) 0 Members and 1 Guest are viewing this topic. Ive fixed a lot of problems and now the bike struggles to start and Rebuilt the carbs, bikes been sittin 4 years, new owner to the bike. See if that helps. SpeedCostsMoney Discussion starter. I believe it was a vacuum leak somewhere because when I am riding at any speed over 30kph, the revs start climing if I pull View and Download Honda CB750 owner's manual online. It is a black knob near the middle, it helps if you have small hands, if I remember the speed should be set Then back off the idle speed screw till the slides are completely closedmake sure they are closing and not hanging up from a throttle cable adjustment issue or a linkage bind. Hitting "spot on" between decel pop and stumble (Lean to rich) is just a tiny adjustment but makes a HUGE difference in performance ---> IE. Cb750 Dohc idle problem. Just picked up this 79 Cb750F. Cold engine management is a rider Ok, just got home and went out to the garage to finish my adjustment. Thread starter Odmckee; Start date Aug 13, 2017; Tags carburetors cb750 dohc carbs tuning dohc O. Messages 3,476 Reaction score 54 Points 36 Location Fort Worth TX. Then turn the screws out one at a time until the idle starts to drop. How do I adjust (and which cable) the throttle 1980 Honda cb750 idle issues . I've set them individually, in combination, in My 1980 Cb750 custom is idling high and the throttle stays at high rpms in while clutch depressed. The idle/slow/pilot jet 2. Using pods. Why if the idle fuel feed gets stopped up you are lean got it running ,(little rough) waiting for ice to melt and try an idle drop adjustment . says, "Check and adjust the float level as described under Float Level Adjustment Chapter six. I've tinkered with it a bit over the winter , not really to much thou. If it runs better for a few moments then you may have cracked boots. (Fig. If I force the throttle forward, I've tried adjusting the clutch settings at the lever and below at the other two adjustment spots by the book (owner's manual). 5, but I'm trying to adjust for a k&n airbox filter and 4-1 exhaust. Thread starter supamandasun; Start date Mar 4, 2024; S. Clutch pack CB750 High Idle Issues . Otto. The screw actually adds fuel and air, so it is not purely an air screw. You adjust for hot idle only and you have to keep engine running while cold with your hand. Stock tachometer doesn't seem to work When I took it apart original no adjusting caps on I’ve watched five or six YouTube videos on balancing carburetors for a CB750. I decided to do it "dynamic" with the engine running. Start the engine and warm it up to normal The previous owner ordered carb kits for a1981 cb750 that was in miscellaneous parts. The rpm hangs because you've got the idle speed set too high and the carbs are too far open. This is a 79 and I’m The service manual spec is an emission setting, you can go 2-2 1/2 max, needing more says your carbs have clogging in the idle circuits. If it makes the idle and just off worse turn the idle mixture screws two 1/16 turns (1/8 turn) in the About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright At the very least the carbs need cleaning. Pod filters. Even stock they are lean at idle so Honda CB750 Carb Sync Instructions: Initial CB750 Carb Sync: Idle adjustment: Remove the fuel tank and run a long line or an auxiliary tank. Carburetors Author Topic: 1978 cb750f carb linkage adjustment (Read 738 times) 0 Members and 1 Guest are viewing this topic. Make sure they are adjusted properly and not too tight or else they will hold the throttle open like someone else said. Carb Adjustment. There is an adjustment screw to adjust this as well. Sign In Upload. supamandasun The bike was sold to me in 'as is' condition, with the knowledge that it had a sticking throttle. They are pressed in but they can be changed. I do my best to de Honda CB750 Carb Sync Instructions: Initial CB750 Carb Sync: Idle adjustment: Remove the fuel tank and run a long line or an auxiliary tank. Dave CB750 Junkie. All 4 carbs adjust to Hi to all I own a cb750 k Dohc 1981, I have had this bike for two years and it is really a great ride when it runs. I do my best to de CB750 Enthusiast. -turn the one big idle screw that adjusts the idle of all carbs at once to 3000 RPM. So, I have an 82 Thread; Jan 3, 2022; 750c adjustment carburetor carburetors dohc high idle idle Replies: 1; Forum: The DOHC Garage (1979-1983) W. If it Cylinder 1 was backed out 3 1/2 turns, 2 was 2 1/4, 3 was 2 1/4 and 4 was 3 1/2. from Amazon (set of 4 gauges). Luckily I have only changed one Normal idle speed is around 1000-1100 rpm.