Author Topic: I'm new to the CB750 (Read 1293 times)

ts354 · « **on:** September 11, 2023, 08:53:44 AM »

So I've worked on several small displacement CB's before, but not the big CB750K models. Just purchased a 1972 CB750 that had been setting for 2 years and right off the bat - "Hmmmm This thing is Waaay low on oil."

Can you guess what happens next? Test ride and I'm spinning the rear tire all the way down the street. "What's all that oil spilling out of the breather tube?"
I do some research and I probably have about 5-6 qts in that thing. No wonder its pumping oil out!

Anything else I need to watch out for?

Thanks for the heads up in advance.

Airborne 82nd · « **Reply #1 on:** September 11, 2023, 10:23:45 AM »

It was not low on oil just in the wrong place. It drained out of the tank and into the pan. Have you done anything to correct this?

ts354 · « **Reply #2 on:** September 11, 2023, 10:27:22 AM »

Yes, I've drained all the oil out now, waiting on a filter, and then going from there. Carbs actually seem to be okay.
Speaking of carbs, the old cheapo pod filters the P. O. had on there are coming apart (unglued). What pods does anyone suggest other than the cheapo Chinese ones? Uni's???

newday777 · « **Reply #3 on:** September 11, 2023, 10:33:15 AM »

Welcome to the 750 sump-n-puke.

If it doesn't correct itself once you ride it a bit you will need to rebuild your oil pump check valve.

Pods? Dump them in the circular file and put the stock airbox back on. Or you'll be fighting for a good running bike.

ts354 · « **Reply #4 on:** September 12, 2023, 08:31:43 AM »

I had a big long thing typed out about the carbs and pods. Lost it when I had to do work instead of play on the internet. Anyway here is a picture of what I'm riding/dealing with.

Airborne 82nd · « **Reply #5 on:** September 12, 2023, 09:54:03 AM »

Don't pull off with that front tie down hooked to the ground

Don R · « **Reply #6 on:** September 12, 2023, 10:07:13 AM »

At the top of this page there is a section on how to run pods.

Don R · « **Reply #7 on:** September 12, 2023, 10:12:06 AM »

Quote from: Airborne 82nd on September 12, 2023, 09:54:03 AM

Don't pull off with that front tie down hooked to the ground

I consulted the official SOHC safety committee, and they said that ground tie is a bad idea! L0L! Is that at the airport?

Nurse Julie · « **Reply #8 on:** September 12, 2023, 01:26:03 PM »

Quote from: Don R on September 12, 2023, 10:12:06 AM

Quote from: Airborne 82nd on September 12, 2023, 09:54:03 AM
Don't pull off with that front tie down hooked to the ground
I consulted the official SOHC safety committee, and they said that ground tie is a bad idea! L0L! Is that at the airport?

🤣🤣🤣🤣🤣🤣

Kaze · « **Reply #9 on:** September 12, 2023, 02:15:55 PM »

Nice Supersport. But either that oil tank is not from that bike, or the bike is not from that oil tank.
New to CB750? Welcome to Heaven. Hope ya gotcher JIS-tipped impact driver.

Kelly E · « **Reply #10 on:** September 12, 2023, 04:39:19 PM »

Quote from: Don R on September 12, 2023, 10:12:06 AM

Quote from: Airborne 82nd on September 12, 2023, 09:54:03 AM
Don't pull off with that front tie down hooked to the ground
I consulted the official SOHC safety committee, and they said that ground tie is a bad idea! L0L! Is that at the airport?

Maybe it's to make sure that your stuff is still parked there in the morning.

HondaMan · « **Reply #11 on:** September 12, 2023, 08:04:45 PM »

Interesting mix of parts: I see an F2/3 frame/wheels and K1-6/F0-1 carbs, aftermarket exhaust, K1-K6 oil tank, CB400F points cover?
What's the unusual-looking tube-over-tube arrangement at the front right upper frame tubes, near the tank?

Don R · « **Reply #12 on:** September 12, 2023, 08:12:49 PM »

HA! I zoomed in and that's a spreader bar on the trailer not a ground lug. Sorry, optical illusion.

Stev-o · « **Reply #13 on:** September 13, 2023, 07:13:33 AM »

Quote from: HondaMan on September 12, 2023, 08:04:45 PM

Interesting mix of parts....

It's a Bitsa! Not there is anything wrong with that.

MauiK3 · « **Reply #14 on:** September 13, 2023, 07:57:44 AM »

Sure isn't a 72
Welcome aboard!
You need to get Hondaman's book, a Honda shop manual and a parts book to be able to tell what it really is and how it works.

It's funny what spell check is always trying to do with Hondaman when I type it.

Floshenbarnical · « **Reply #15 on:** September 13, 2023, 08:45:10 AM »

Quote from: ts354 on September 12, 2023, 08:31:43 AM

I had a big long thing typed out about the carbs and pods. Lost it when I had to do work instead of play on the internet. Anyway here is a picture of what I'm riding/dealing with.

That bike is a schizophrenic Frankenstein's monster of parts and I love it

Time to find an airbox on eBay or some PD carbs, though. The pods thread sticked at the top of this sub folder was educational for me and made me thank my lucky stars I have PD carbs.

ts354 · « **Reply #16 on:** September 13, 2023, 09:14:28 AM »

Hondaman; Floshenbarnical - Yes, there are very many different years/model variations represented in this example of a motorcycle.

I'll try and get a pic with the seat on tonight.

HondaMan · « **Reply #17 on:** September 13, 2023, 07:57:31 PM »

I think it needs a sissy bar to be complete...

scottly · « **Reply #18 on:** September 13, 2023, 08:10:28 PM »

Quote from: ts354 on September 11, 2023, 08:53:44 AM

Test ride and I'm spinning the rear tire all the way down the street. "What's all that oil spilling out of the breather tube?"

Since you have an early oil tank and an early engine in your F2/F3 bike, you should have both a breather tube,from the oil tank and one from the cam cover; both should be routed down on the right side near the swing-arm pivot, out of the way of the tire.

Also, your early oil tank should have a drain tube on the back side that is connected to the nipple on the back of the crankcase.
What are the serial numbers on the engine and frame? What is the chain size: the early 750's used 530 chains and sprockets, but the late K and F models used 630. Stock gearing for the
F2/F3 was 15 front, 42 or 43 rear, IIRC. The offset of the front sprocket was also different.
The good news is that you have the late F front forks with the option to improve the brakes using factory parts, as well as the stock rear disk. I also see an aftermarket fork-brace.

ts354 · « **Reply #19 on:** September 16, 2023, 04:58:08 PM »

Scottly, I'll get that info in a minute, but first here's a quick video. Well, maybe not. Can we post videos? Well here's a pic anyway.

ts354 · « **Reply #20 on:** September 16, 2023, 05:06:29 PM »

Video Linky

Stev-o · « **Reply #21 on:** October 17, 2023, 10:02:30 AM »

Sounds pretty good, how does it ride?

Jcop.550 · « **Reply #22 on:** October 17, 2023, 11:46:05 AM »

Welcome! Looking forward to seeing the progress.

By the way, this is Jake from fb marketplace - I sold you a couple parts! Recognized the bike from the pics you sent on messenger.

Sent from my iPhone using Tapatalk

Kaze · « **Reply #23 on:** October 18, 2023, 03:56:52 PM »

That's one hot lookin' bike.

ts354 · « **Reply #24 on:** October 30, 2023, 08:07:41 AM »

Wow, I guess I'm not getting notifications of responses to this thread - or they may be going into my junk mail folder, I'll have to check.

Stev-O; Actually rides pretty good.

Jcop.550; Hey!!! good to see you on here. Got the parts and everything looks good, I just need to motivate myself to go out to the cold dark garage and put them on!

Kaze; Thanks!, it's a pretty solid bike. Just needs some maintenance, new chain/sprockets, couple of gaskets etc...

News:

Author Topic: I'm new to the CB750 (Read 1293 times)