Author Topic: Starting issues  (Read 425 times)

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Offline SantaFeHonda

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Starting issues
« on: September 08, 2024, 11:20:19 AM »
1977 CB750K. I just got this bike a few weeks ago and have only ridden it a couple of times so far. When I first got it it seemed to start up with no problem. It has now gotten to where it won't start without several tries and constant recharging of the battery. It sounds like it's not getting gas but after trying to start it for a while it starts to smell like it's flooded. Any suggestions where I might start looking for causes?
« Last Edit: September 08, 2024, 11:22:09 AM by SantaFeHonda »

Offline scottly

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Re: Starting issues
« Reply #1 on: September 08, 2024, 11:23:26 AM »
Check your spark plugs: are they clean and dry? Sooty and dry? Sooty and wet? Clean and wet?
Don't fix it if it ain't broke!
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Offline bryanj

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Re: Starting issues
« Reply #2 on: September 08, 2024, 11:38:52 AM »
What type of carbs has it got
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline SantaFeHonda

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Re: Starting issues
« Reply #3 on: September 08, 2024, 11:48:14 AM »
The plugs are relatively new and look clean. The carbs are Kei Hin. Additionally, when I do get it to start it runs great with no smoke from the pipes.
 

Offline HondaMan

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Re: Starting issues
« Reply #4 on: September 08, 2024, 12:09:04 PM »
This might seem like an odd question (since I don't know your experience with these bikes?) but...are you familiar with the 1970s- style fuel petcock operation on the fuel tank?

I once tried to 'help' someone for several days before I discovered his 750 was the first motorcycle he'd ever owned, and he didn't understand how the fuel has to be turned OFF when parked and ON or RESERVE when running. :(
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

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Offline SantaFeHonda

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Re: Starting issues
« Reply #5 on: September 08, 2024, 12:30:33 PM »
Yes, I've owned a couple of bikes, a 1974 CB750 back in the 70's and 80's. I just got back here after pulling the plugs to inspect them and after putting them back in it decided to start. I'm going to take it out for a quick run and see how it runs now.

Offline bryanj

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Re: Starting issues
« Reply #6 on: September 08, 2024, 12:51:59 PM »
All the 750 have Keihn carbs but its the type that matters, is the top a round screw on or a P shape held on with 2 cross point screws
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline SantaFeHonda

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Re: Starting issues
« Reply #7 on: September 08, 2024, 04:03:16 PM »
I'll have to go check the carbs. More tomorrow.


Offline Don R

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Re: Starting issues
« Reply #8 on: September 08, 2024, 05:16:54 PM »
 A 77 didn't come with the round top carburetors but they often get installed due to the lean characteristics of the 77 carbs .
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Offline newday777

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Re: Starting issues
« Reply #9 on: September 08, 2024, 06:26:59 PM »
What type of carbs has it got

Looking at his posts he has roundtops.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline bryanj

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Re: Starting issues
« Reply #10 on: September 08, 2024, 06:31:12 PM »
I know the F had the problematic PD carbs but the K was rare in UK so i dont know about that one which is why i asked
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline newday777

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Re: Starting issues
« Reply #11 on: September 08, 2024, 06:40:24 PM »
I'll have to go check the carbs. More tomorrow.

Looking at your posts someone has put roundtop carbs on your K7 frame.

Look at the flat surface on the motor side of the slide to get the body numbers
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline HondaMan

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Re: Starting issues
« Reply #12 on: September 09, 2024, 08:13:39 PM »
What type of carbs has it got

Looking at his posts he has roundtops.

That shot looks like a K4/5?
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline BenelliSEI

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Re: Starting issues
« Reply #13 on: September 10, 2024, 10:22:36 AM »
What type of carbs has it got

Looking at his posts he has roundtops.

That shot looks like a K4/5?

It’s a “bitsa”. Very nicely done too!