1981 CB750K - Repair/Tune-up

classic Classic list List threaded Threaded
539 messages Options
1 ... 6789101112 ... 27
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

shinyribs
Administrator
Glad you got to ride,even if wasn't perfect.Good luck with the job hunts...ever consider playing the lottery? I hear it's nice.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Of course I did! Put $40 down when it was so high, and won $4 back! 

Is 70 mph @ 6k rpm normal? I would've thought they can do better than that... hell, I bet the Suzuki I looked at could've done the same given that it's got a 6th gear! 

On Wed, Apr 18, 2012 at 11:33 AM, shinyribs [via Honda CB750'S] <[hidden email]> wrote:
Glad you got to ride,even if wasn't perfect.Good luck with the job hunts...ever consider playing the lottery? I hear it's nice.
Montvale,Virginia
 Piute said it best:  "wheres my 10mm?"
Hellbilly-"that is a great way to tell if you have come to your senses, when you start drilling random holes in things... "

Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato








If you reply to this email, your message will be added to the discussion below:
http://honda-cb750-s.456789.n3.nabble.com/1981-CB750K-Repair-Tune-up-tp3846604p3920369.html
To unsubscribe from 1981 CB750K - Repair/Tune-up, click here.
NAML

Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

shinyribs
Administrator
My bike is geared slightly lower than stock and it turns 5k rpm at 70mph,so yeah,yours does sound a bit high. it's seems like your killing the poor thing running it that wound up,but I regularly get 45-50 mpg on the highway...depending on how much playing I have been doing.I have never gotten below lower 40's mpg.

Cutting out in high gear sounds like you mat have some sort of fuel delivery problem.Probably either a clogged petcock/fuel filter/fuel line or maybe the floats are a little low.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Ya, I'm betting it's something in the carbs.

Went out for a helluva ride today. Got to the gas station (since last ride I had to flip to reserve) and I had 67 miles on it. Filled up, reset the odometer, and took off. I went to a buddy's yesterday to help him pull the motor from a Z28 yesterday, and he was pissed that the exhaust wasn't fitting back up after replacing the oil pan - previous owner had beaten it and stopped leaks with JB Weld. So I went to his work to show him the bike and offer to help him get the exhaust resolved. He wasn't there, so then I decided to go a bit further and see if a buddy of mine was home. In Wayland, another 15 miles in the wrong direction.

After seeing him, went back to first buddy's work, where he was, and talked to him some. Then rode home.

86 miles put on 'er today. So I've more than doubled my miles now. I've also started tracking my fuel economy on fuelly - I track it for the truck and my Integra, so now time to add the bike to the fleet.

In the next couple weeks, I'm going to order up the stuff to do my carbs, as well as possibly look into my motor stuff. I'm betting my 6k rpm @ 65 mph is due to my motor needing to be rebuilt. Because it's so low on power, it takes more revs to make the same power.

In other news, I find out this week if I'm first pick for University of Michigan's open networking position. Here's to hoping...
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

shinyribs
Administrator
Your RPMs at sixty mph will never change. Unless you change your gearing, of course. You gotta straight drive with a clutch. If aint slipping then your  are looking at whatever rpm you are gonna be running from now on.

Regardless,glad you got to ride! Keep it up cdaiscold !
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Hmm. I thought it was because it was taking more RPMs to make the same horsepower. 

I wonder if the clutch is slipping then. Wouldn't surprise me, this bike then. I'm || that close to just selling this and getting something else. I am quite tired of seeing problem, after problem, after problem, after problem crop up. I am about to just say screw it, sell this one, buy a bike for like $800, and try a 2nd time with doing it proper. Even though I've JUST put insurance on it a few weeks ago and everything else. 

Ugh. Something cannot be right with the trans, because this CAN'T be a 6k+ rpm @ 70 mph. If I want to do 80 mph to DC with my dad, this isn't the bike to do that on. And that was SPECIFICALLY why I bought this bike. 

Not sure what I'm going to do now. I'm not going to have a CB750 that's perfect for 55 mph biking. Fuck that. 

On Sun, Apr 22, 2012 at 10:02 PM, shinyribs [via Honda CB750'S] <[hidden email]> wrote:
Your RPMs at sixty mph will never change. Unless you change your gearing, of course. You gotta straight drive with a clutch. If aint slipping then your  are looking at whatever rpm you are gonna be running from now on.

Regardless,glad you got to ride! Keep it up cdaiscold !
Montvale,Virginia
 Piute said it best:  "wheres my 10mm?"
Hellbilly-"that is a great way to tell if you have come to your senses, when you start drilling random holes in things... "

Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato








If you reply to this email, your message will be added to the discussion below:
http://honda-cb750-s.456789.n3.nabble.com/1981-CB750K-Repair-Tune-up-tp3846604p3931345.html
To unsubscribe from 1981 CB750K - Repair/Tune-up, click here.
NAML

Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

TOOLS1
Administrator
Count the number of teeth on your sprockets, and divide the smaller number by the bigger number. That will give, you the gear ratio. Then figure out what ratio, you want, and change it. These were not 55 MPH bikes!!! Now quit bitching, and fix it!!!!!!
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
I will do that. Any idea what was stock on these things? Count on the front and rear?

I'm counting them sometime this week, that's for sure. Definitely don't want a 55 mph bike, I want a 100+ mph bike if possible so I don't wear out the bike at 80 on the highway for multiple hours!


But she does bring a big smile to my face. A big smile.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
So, I think what I'm going to go with for my eventual overhaul:

-823 kit from CycleX
-HD studs
-Randakk carb rebuild kit
-900 cams - difference between 900c and 900f? What years would work in my 81K?
-Dyno tune

Alternatively, I may just cheap out, put rings into this one, and buy a bigger bike. I know that's what my dad suggests.


I don't even know why I'm thinking about this now. Going to ride this thing in town, and start working on the car. I am getting sick and tired of not getting further on that. I have people to beat and take money from... :D
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

shinyribs
Administrator
Tools is right.Check your sprockets.See if somebody geared the piss out of it.

You got your brakes straightened out and you KNOW that motor is clean inside.There couldn't be too much wrong with it.Just takes time man.You'll get it. If your gearing checks out ok you might wanna check into seeing if your tach is off.Is it the factory tack that belongs on that bike? See if you can find someone with a clip on tach. One that reads off an inductive pickup like a timing light. You can verify your tach that way.
Oooor,maybe your tach is cool and your speedo is off.Hey,ever heard of trapster?SOMEBODY turned me on to it...its really cool

Stock gearing on a SOHC K was 18-45.  My F has 18-48.With a 120 rear tire it runs 5k @70.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool

What's this program? Sounds like something a cop would want you to use!

As for the speedo, I verified with my dads Goldwing that the speedo is nearly perfect, a couple mph off at best. I have to do some stuff for my dad the next couple days after work, and back to my Camaro buddy's Friday and Saturday. So we will see when I get time for the 750.

I am largely thinking new sprockets and 530 chain is on order soon. And depending on up and coming cash, the other work too. I at least want to get her running as well as I can.  Do the chain, sprockets, and carbs and see what I can get for the rest of the year for riding time.

On Apr 23, 2012 12:42 AM, "shinyribs [via Honda CB750'S]" <[hidden email]> wrote:
Tools is right.Check your sprockets.See if somebody geared the piss out of it.

You got your brakes straightened out and you KNOW that motor is clean inside.There couldn't be too much wrong with it.Just takes time man.You'll get it. If your gearing checks out ok you might wanna check into seeing if your tach is off.Is it the factory tack that belongs on that bike? See if you can find someone with a clip on tach. One that reads off an inductive pickup like a timing light. You can verify your tach that way.
Oooor,maybe your tach is cool and your speedo is off.Hey,ever heard of trapster?SOMEBODY turned me on to it...its really cool

Stock gearing on a SOHC K was 18-45.  My F has 18-48.With a 120 rear tire it runs 5k @70.
Montvale,Virginia
 Piute said it best:  "wheres my 10mm?"
Hellbilly-"that is a great way to tell if you have come to your senses, when you start drilling random holes in things... "

Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato








If you reply to this email, your message will be added to the discussion below:
http://honda-cb750-s.456789.n3.nabble.com/1981-CB750K-Repair-Tune-up-tp3846604p3931518.html
To unsubscribe from 1981 CB750K - Repair/Tune-up, click here.
NAML
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

Hellbilly429
These bikes are just geared really low, mine does about 6k rpms at 60-65mph so its not just your bike. My dad used to own an '81 and said they are stop-light bikes, meant to take off fast but not go fast, hence why the speedometer only goes to 80mph.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Hmm. That's the first I'd heard these being 55 mph bikes. My dad had an SOHC, and said that he remembers some high-speed stunts on his.

He is also starting to try talking me into not modifying my 750, but instead picking up an 1100 lol. Sat me on his 1200 Goldwing today, and told me once I'm licensed I'm taking it out to experience the power.

I have to look more at the gearing. I think I'll have some time tomorrow to check the gearing and see what it is, compared to stock.

Perhaps I can -finally- get the brakes done on the Integra. Naaaahhhh.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
In reply to this post by Hellbilly429
Hmm. That's the first I'd heard these being 55 mph bikes. My dad had an SOHC, and said that he remembers some high-speed stunts on his.

He is also starting to try talking me into not modifying my 750, but instead picking up an 1100 lol. Sat me on his 1200 Goldwing today, and told me once I'm licensed I'm taking it out to experience the power.

I have to look more at the gearing. I think I'll have some time tomorrow to check the gearing and see what it is, compared to stock.

Perhaps I can -finally- get the brakes done on the Integra. Naaaahhhh.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

shinyribs
Administrator
Seems strange to me ,too.I know the SOHC's will do 100+ easy.I couldn't imagine the DOHC's not. They have more HP,they should be able to pull more gear than a SOHC.Maybe Honda geared the piss out of them for seat of the pants feel? Hmmm,i'm interested in all of this.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Hmm. I responded by e-mail but it isn't coming up apparently.


Ya, as I've said, I think the gearing's off. I've verified my roommate has tomorrow off, so I am going to count teeth tomorrow.


I'm going to possibly remove the carbs and just do a cleaning for now. I'm just hoping tomorrow morning I get an e-mail that says I'm moving to Ann Arbor. Perhaps I'll just get a carb rebuild and carb sync tools in the next few weeks. Start working on making it run better.

Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

Hellbilly429
In reply to this post by cdaiscool
Might just be the K models geared low since they seem to be geared more towards touring than racing.

Sent from my HTC Inspire™ 4G on AT&T

----- Reply message -----
From: "cdaiscool [via Honda CB750&apos;S]" <[hidden email]>
To: "Hellbilly429" <[hidden email]>
Subject: 1981 CB750K - Repair/Tune-up
Date: Mon, Apr 23, 2012 11:53 pm


Hmm. That's the first I'd heard these being 55 mph bikes. My dad had an SOHC, and said that he remembers some high-speed stunts on his.

He is also starting to try talking me into not modifying my 750, but instead picking up an 1100 lol. Sat me on his 1200 Goldwing today, and told me once I'm licensed I'm taking it out to experience the power.

I have to look more at the gearing. I think I'll have some time tomorrow to check the gearing and see what it is, compared to stock.

Perhaps I can -finally- get the brakes done on the Integra. Naaaahhhh.


If you reply to this email, your message will be added to the discussion below:
http://honda-cb750-s.456789.n3.nabble.com/1981-CB750K-Repair-Tune-up-tp3846604p3934303.html
To unsubscribe from 1981 CB750K - Repair/Tune-up, click here.
NAML
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Perhaps. Either way, I need to change this. I'm not a fan of having a 750 that's a street bike. I bought this to get me to DC, and I'll be damned if I can't get there on this one.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Ut oh. So I'm trying to get the foot peg off to remove the front sprocket cover, to see the number of teeth...

AND THE BOLT WON'T COME OFF.



It's just spinning in its little hole. And I don't see a nut holding it on. So, what holds that bolt in place? Is the frame itself what it goes into, and that is stripped? Causing the bolt to refuse to come out? Or is the nut somewhere I can't see, that is spinning and needs to be held down?

I've tried with a wrench AND with a socket. I haven't put an impact on it, but that's only because I can't find my 3/4 socket for the impact, and I can't find my 1/2>3/8 adapter to use the 3/8 socket.

I've already found 1 welded nut that was spinning, so I won't be surprised if there's more on this thing.


Help?
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
Reply | Threaded
Open this post in threaded view
|

Re: 1981 CB750K - Repair/Tune-up

cdaiscool
Well, just like any other time, after I ask for help...

I found a 19 mm, 1/2 drive, and put that on my impact. came right off. Odd.

But since I've got you here....


Sometimes, this bike fights to go into neutral. I'm not sure if it's just not dropping down to gear or if it's saying between 2 and 3, or if neutral just refuses to take. Any suggestions?
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
1 ... 6789101112 ... 27