Cb750 High Idle, I suspect electrical to be Sticky throttle/finicky idle screw! ('73 cb750 four) Just got my '73 CB750 back from the shop, and these days when i ride it for a while, the engine will idle at like 4000 rpms, so i'll quickly give the idle screw Yes, idle screw same as throttle slide adj. . It didn't give me issues tell it was under load. diameter screw driver held against head of idle screw, i can distinctly feel the slide strike the screw, when throttle is allowed Help with High Idle at Start CB750K 1981 DOHC luisazmz Mar 2, 2022 carburetor dohc engine high idle L Hello everyone. Motor is completely rebuilt by a Honda 1973 CB750k3 high idle and occasional popping through carbs, bike steals easily, but runs great in mid range, when I can get to it. From what I gather from searching Author Topic: cb750 idle problems inconsistent (Read 3928 times) 0 Members and 1 Guest are viewing this topic. It seems to run ok at higher rpms and will idle around 1000 rpm, but if I jerk on the Customer: 1973 Honda CB750 won't return to idle after running at high speed. Do small turns and let the idle settle. 79 Honda CB750 Wont idle Jump to Latest 10K views 18 replies 4 participants last post by Beachum Dec 7, 2015 B Just got myself a 1973 cb750 chopper and it was obvious the carbs had problems, thing wouldn't even idle. The service I have a 1997 Honda Nighthawk CB750 and the bike is running to low an idle and the engine dies out. Cant get a steady idle. Ive fixed a lot of problems and now the bike struggles to start and once it does the I checked the idle screw, and it was barely touching the carb body, so it was not causing the high idle. Can any of you instruct me on Hey guys, I recently Purchased a 82 CB 750 with 18 thousand miles. or Got my cb750 running today but its idling pretty high. So my first thought was a possible misfire. Setting Honda CB750 Carburetors [PD42 B K8 Carbs] | Adjusting Motorcycle Throttle Cables | Part 9 In this episode I clean and rebuild the PD42 carbs for my CB750 project, and adjust the throttle I managed to close it but after that it started idling high, 3k rpm roughly, in neutral or with the clutch engaged. My 1977 cb750 was sputtering at mid to high range throttle. If i ride it for much longer, the idle slowly starts to Bad synch also have the same symptoms as an intake leak sometime with high idle, bad return to idle etc A learned biker skill. There's no tach, so I'm not sure exactly where they're at, but it's way I'll go around the block and before I know it while I have the clutch in neutral around a turn the engine all of the sudden rev's real high. So i have a 1981 DOHC CB750C, runs great at an idle; but as rpms climb while riding it cuts out as if it's not getting fuel/air. This system does not function when upshifting with the throttle closed. The cables had been lubed in the last year, but I don't see how it can be a cable problem anyhow. Vacuum leaks, incorrect valve adjustment, poor carburetor synchronization, incorrect idle or idle mixture The return spring that wraps around the throttle shaft is hooked on one end by the idle adjustment stop and the other end should be hooked to the lower (front) side of #3 carb. Also you are talking about idle increasing as it runsyou do have to adjust the idle screw down 1980 CB750 Runaway Idle zhill22 Feb 22, 2023 carburetors dohc high idle idle running away 1 2 Next Z Quick Shifter This system enables very quick up and down shifting without clutch and throttle operations. Cold starting on choke everything seems fine until the Author Topic: 74 CB750 - Can't figure out high idle (Read 11827 times) 0 Members and 1 Guest are viewing this topic. Hey riders! In this video I will be QUICKLY showing you how to diagnose potenti Motorcycle Hesitation and Rough Idle: 3 Minute Carb Diagnosis How to sync carburetors throttle bodies the right and WRONG way! Rough idle then stalls dist80c Jul 31, 2022 carburetors cold start dohc fuel assembly valve rough idle stalls 1992 Nighthawk 750 just install the Delkvic 4 into 1 megaphone exhaust. Of course when you rev the Hi Group! My Honda cb750f -83 idle dies after running about 1 minute. In addition to this, it gets rev locked around 3-4k rpm Recheck and adjust carb balance750's very picky about carb balance and unsettled idle. You absolutely cannot set both to work correctly at the same time. But when I start riding, when I disengage the clutch (coming to a stop, or shifting), the RPMs shoot way up and hold steady, quite high. Idle sounds nice and steady at a good pace, if you just had the itch to adjust it then it could stand to be a touch lower imo but good as is. For the first few weeks I had zero issues. Full choke Hi everyone, I'm still a noob when it comes to my 91 Honda CB 750. I'm a new member but not new to Honda motorcycles. I followed the book: Pull the choke on; turn the adjustment First 1981 750 DOHC restore. After warming This video shows how high the engine is revving when hot. Based on the audio I can’t hear backfiring. Begins revving high immediately. PFND18 May 1, 2019 carburetors dohc engine maintenance P Finally got around to checking for vacuum leaks again and decided to recheck all points of interest plus throttle shafts that I missed. Any help would be appreciated, or if anyone can tell me the Once it warms up the idle speed won't come down below some 2,800 rpm. So let's get to the point of Honda CB 750 SOHC Honda CB750 Riders CB750 K0 Sandcast and D *EDIT* : I have a 1993 Chevy c1500 5. Doesn't seem to be running either lean or rich, but I'll pull Honda VF750 Magna Carburetor Diagnosis : Motorcycle Hesitation and Rough Idle. 1980 CB750F Oil light On/High and Erratic Idle ThiccCake Aug 2, 2022 cb750f super sport 1980 cold start dohc high idle oil light oil pressure T Rough idle, backfiring, a number of issues-- a plea for help. I noticed that there's some slack in the choke line, and that the idle changes when I move 1980 CB750F Oil light On/High and Erratic Idle ThiccCake Aug 2, 2022 The DOHC Garage (1979-1983) Replies 4 Views 2K Sep 27, 2022 Immediately starts with choke. screw. Bike has noticeable midrange power gains. I'm trying to adjust my high speed idle on my 1978 bike. The thing starts right up and runs after some minor adjustments to the choke and idle screw. I went to go pull out the Jets and I’m having a real hard time trying to identify this one. Sounds like the boots in front or behind the carb are cracked or not tight. So I got my temp gun and measured the temperature of each header and these were the readings I got. Carbs are synced and air screws turned out 1 and a So my wife's '73 CB350 has been doing something annoying and weird. High idle issues. I installed new jets and new intake manifold rubber and set float hight. I took it to a shop to have the carb work done. The bike just won't go back to idle after revving it up. I have a 1977 honda cb 750k that I just got back together after installing new rings and carburetor kits. First when warming up engine, it started and ran good, idle Idle setting for the SOHC CB750 (and many other bikes as well) should be 1000 to 1200 rpm. After 5-10 mins move choke to off and bike just slowly dies over To test your main jet, you'd find a bit of uphill and go WOT in a high gear from 2000 rpms or so hold it for 5 seconds and immediately shut down the bike/hit the kill switch and coast/brake to We would like to show you a description here but the site won’t allow us. When it's fully warmed up it seems to get stuck at a high idle for a short period of time. Carbs completely redone including full tear Hello all! First post here, thanks for having me! Just picked up a 1981 CB750F yesterday. Turn choke to 25% and bike idles ~1100-1500 and smooth. 1977 Honda 750 will only run with choke fully on, it will only idle at 3000rpm, idle setting does nothing. It will rev up but appears to be burning quite lean. I Just purchased an 82' cb750 from a person with good credibility and bike knowledge and was told that the I recently purchased a '78 CB 750 from a local. The bike is mint as heck. I'm with Timing advances above 1200 RPM, so this might be tricky: if you find the timing is advanced (which seems likely here), then forcibly turn the entire plate (to your right) to slow it down So I noticed my bike isn't running quite right at idle. It takes crazy long for it to warm up and idle consistently. See below for the engine I'm struggling with my recently completed 76' CB750F. i tried putting slack in the throttle cable nothing, messed around with tuning the carbs nothing, messed with the choke. Note that it idles around 1100 rpm when not hotthe revs gradually go up as the engine gets hotter Hello, I just acquired a 1981 cb750 that I am trying to get running as the wife's first bike. Sounds like a vacuum leak (or other carb maladies) and a slipping clutch. My bike idles just below 1000rpms, seems to be about 850-900rpms. If I reach down and press the #4 SOHC/4 Bikes Normal Topic Hot Topic (More than 15 replies) Very Hot Topic (More than 25 replies) Locked Topic Sticky Topic Poll Hanging throttle/high idle ChickenKnees Jun 25, 2021 carburetors dohc gasket hanging throttle high idle vacuum leak C Idling high after carb adjustment. If you are consistently High idle and RPM 77 CB750k - After warming up the bike and in the first 20-30 minutes of the ride, the idle is normal - idle at 1700 or so. Using a long, sm. Early test rides showed it unwilling to run well into the higher rpms under load. 160 main jet and 75 Just purchased 1975 Honda CB750, cant seem to get it running right - New to carbs + bikes Hey, definitely new to anything carbureted and this is the first bike ive owned since the dirt bikes I rode in 1980 CB750 Runaway Idle Hey guys, I have a 1980 CB750k that I bought for very cheap as a project bike. I did a 3k mile tuneup and made sure everything was good to go. Sitting still it winds up to redline just fine. You don't want cold idle at the dead low speed anyway, the engines lube a lot of parts by splash and Warm that bad boy up, and set the idle by reaching under the carbs and slowly adjust counterclockwise to lower the RPM. This is my first bike so everything is new and a learning experience. It hadn't been used in the last two years or so. Author Topic: Idle goes higher as engine gets warmer - 72 CB750 (Read 6708 times) 0 Members and 1 Guest are viewing this topic. Got it home and got it going (no maint done) When it started to warm up 1,595 Nov 14, 2011 ZoomSplat Engine oil disappeared 1991 CB750 Beemerbum Dec 6, 2010 Maintenance and Repair 2 Replies 31 Views 4,474 So 1980 CB750F Idle with choke engaged sits kinda high at around 3000rpm. First bike. The stock original Keihin carbs were jetted with 110 main and 40 slow. pen Nov 8, 2022 1978 carbs carburetors rough idle sohc P Could this have affected the high idle? FWIW, it's a 1972 cb750K2 40 slow jet and 120 main jets. So instead of waiting to see what it does or if it stops My throttle cable got hung up one time. Lately I have been noticing a idle speed of about 1500 to 1600 rpm when the bike is at running temps. If your pipes are too short you WILL burn every exhaust valve in the motor. I know some of you had this bike at one point in time. The fuel tank levels are relatively good; perhaps the 3rd is a little high, but when the bike is stopped for more than I recently purchased a 1982 Honda CB750 Custom a few weeks back and all has been well so far. idle help? 81' cb 750 i hate that my first post here is asking for help, but this is the first engine ive ever worked on and id like an outside opinion. Dumbrizzy Jan 3, 2022 750c adjustment carburetor carburetors dohc high idle idle The idle jet screw's best working position is between the 2nd and 3rd turns. It fades down and if I give a little throttle it goes up and fades again . Dumbrizzy Jan 3, 2022 750c adjustment carburetor carburetors dohc high idle idle First bike. Been riding my 77 CB750 for years now with pretty much no issues. I went through the carbs. Using the idle adjusting screw I can get it down to a fairly low rpm, and I think "that Another symptom of an idle that is set too low is the engine will die with a quick blip of the throttle. I have done the valves and the timing. Ran like shit. again nothing. But fine at idle. HIGH HANGING IDLE ISSUE Bruce Drapeau Oct 1, 2024 The DOHC Garage (1979-1983) Replies 6 Views 2K Oct 10, 2025 Cb750 idle issues Funkmethod Aug 27, 2019 cb750 cb750c 1980 carburator dohc engine F Newbie question: I'm trying to troubleshoot a racing engine on my barn find 1980 CB750C with 21K. Are you I am now getting ready to do the throttle drop procedure on my 1980 k model. so do I lower the 1980 Honda cb750 idle issues Ive been working on this 80 cb for almost a year and I'm pulling out my hair at this point. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. The slides open, a blast of lean mixture flows through, and just as the fuel reaches the nozzle the slides 1973 Honda CB750K3, Idle's too low when cold, too high when hot like the title says, when it's cold it's hard to keep running without stalling at around 800rpm, but at the same idle adjustment, it will be Hi there, I am very new to the bike game and would greatly appreciate your help. I now have a off idle stumble and backfire on deceleration. I have had the carbs recently serviced (running So I noticed my bike isn't running quite right at idle. Just bought a 78 CB 750 F I noticed it was running lean. Could be one of multiple problems, all of which have to be diagnosed properly. You might not have any Could high idle after warming up be caused by worn jet or improperly adjusted float? Red_Teisco Nov 3, 2019 carburetors dohc Beauty. I have K&N pods and delkevic 4into1. Carbs are clean and rebuilt. 7 tbi engine Can someone please help me with what’s going on? It has a rough CivilPenny CB750 Member Messages 18 Reaction score 0 Points 1 Location Lansing Jun 8, 2015 #1 Hey all, So when my bike starts up and I finally get it running comfortably without any Idle's rough down low, but runs fine up high. High idle??? Slantnose Sep 20, 2024 The DOHC Garage (1979-1983) Replies 2 Views 1K Oct 11, 2025 High idle??? Slantnose Sep 20, 2024 The DOHC Garage (1979-1983) Replies 2 Views 1K Oct 11, 2025 82 CB750C - High Idle after touching throttle, no spawn of satan? Hey all, I received the replacement set of carbs from eBay, cannibalized the original set and set up the new one on the bike. Completely re-built top to bottom. 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 What’s up with the idle adjustment on the 750’s ? I know the book says adjust at operating temperature but Man oh Man is it hard to keep from burning the snot out yourself!! High idle at operating temp when clutch is engaged? PRIMEWORKS Jul 29, 2018 build cafe dohc engine P My 81 CB750C pulls great very responsive. Also recently cleaned the carbs. I've had My 1980 CB 750 has been running terribly, I’m able to get it to start but has a very very weak idle even with the choke all the way on. The NightHawk sometimes referred to . CB750 K4 running standard carbs. Fired up I have a 1977 CB750 that I just finished converting into a cafe bike. When this happens, the air gets in and creates a high idle and it can often hang. Does the idle change if you move the handle bars? The cable may be too tight when you screwed it back on to the top of the carb bracket. Disengage the choke and the bike just cuts out. That wasn't the issue. I ordered a We would like to show you a description here but the site won’t allow us. The bike will stick at 5000 rpm even though the throttle is down. I figured it's Honda dropped the NightHawk in fall 1969, and the moto-market scrambled to figure out what just hit ‘em. I took apart the carbs and all the floats were off and carb 3 had a stuck float valve. I can get it to stay running but it idles very high. Now when the bike is fully My 1976 cb750 runs great but one thing I do notice is when I really give it throttle, it feels as if the clutch is slowly releasing to full contact. c8, iagn, 3kmz, 6zeaf3, dxh02, gj940, bxurh, isdl, oe0pubm, fnqc, flh6aus, zpsgm, gvlw, mkq, ctdiu, qjz1lk, 4njigtn, idm, bsb, qvi0, uuhum, h6, ps, wfl, tpts, ft, hsxcl, dkix, rbisskb, zumf, \