Dump your advice here! 81 cb750f

[macepatrick]

One step forward, two steps back!
Got the muffler mounted finally. New brake pads and missing pieces arrived, got everything installed. Just need to get some brake fluid and bleed everything. Unfortunately, shes finally sat long enough to need the carbs redone for real. Needed full choke and some throttle to get it to start, then it was very bogged down of course. It could break free and start getting to about 3k rpms, but fuel started pouring from all 4 overflows at the bottoms of the carb bowls. I didnt want to start a fire, so I stopped there. Closed the petcock and cranked it a few more times just to burn any fuel in the cylinders. Put the battery on the charger for a while, tried to crank one last time and she wouldnt give it to me. Im guessing fouled plugs. These plugs werent bad , and I cleaned them up a little, but Ill buy some new hot ones for until I get this running smooth. So, its a slow go, but Ill get it right at some point.
I need machined billet piece (stopper) that sits in the end of the frame for the chain tensioners to work against, if anyone has one. I have the one on the chain side, but not the other side. If you have one youre willing to part with for a reasonable price, like less than $20, please send me a message!

 

[macepatrick]

I guess the carb stack came off of an 82 custom? or something,, the rebuild kits I bought had different float valves, emulsion tube, and needle tube. Always get your old parts in your hands first before you order new parts hahaha. I know this rule from working on cars so many times, but Ive been too anxious to keep this project rolling.
I got the carbs cleaned up and reinstalled. She idles , but needs full choke. The other day I did manage to get it dialed in to idle with no choke , but it only lasted a minute or so. Its been quite finicky.
Crush washers for the brake banjos and the missing chain tensioner stopper have been ordered, so I should be able to wrap everything up soon. Maybe with my days off this week I will install the body panels and get all the lights working.

 

[Trkdrvr1376]

I guess the carb stack came off of an 82 custom? or something,, the rebuild kits I bought had different float valves, emulsion tube, and needle tube. Always get your old parts in your hands first before you order new parts hahaha. I know this rule from working on cars so many times, but Ive been too anxious to keep this project rolling.
I got the carbs cleaned up and reinstalled. She idles , but needs full choke. The other day I did manage to get it dialed in to idle with no choke , but it only lasted a minute or so. Its been quite finicky.
Crush washers for the brake banjos and the missing chain tensioner stopper have been ordered, so I should be able to wrap everything up soon. Maybe with my days off this week I will install the body panels and get all the lights working.

Pay close attention to making sure that there are no air leaks between carbs manifold and air box I have had issues with this and if you have air leaks you will be chasing your tail forever. With the bike running spray starting fluid if rpm’s fluctuates you have leaks . Hope this helps and good luck

 

[Texaspolecat]

Keep plugging away. Back off when you get frustrated, especially when working on carbs, and at the end you will have a great bike. Bought a 1981 CB750c for 760.00 and now have only 2180.00 in the project. Working on decal design for fuel tank.

 

[macepatrick]

Keep plugging away. Back off when you get frustrated, especially when working on carbs, and at the end you will have a great bike. Bought a 1981 CB750c for 760.00 and now have only 2180.00 in the project. Working on decal design for fuel tank.View attachment 20716View attachment 20717

i like that seat

 

[macepatrick]

Its been a month. Been working on the brakes the whole time. The pistons were hella stuck in the bores.. finally got them all out. Hoping I dont also need to buy new brake lines, but something tells me I should just bite the bullet and do it anyway. New O- Rings and rubbers in for the caliper rebuilds, so hopefully there will be a positive update with some actual progression coming soon.
I still think I need to find new float valves in the carbs, but I havent been able to find a kit with the exact match of needle and emulsifier tubes,, everything else is slightly different, including in the last carb rebuild kit I bought. Also in that kit the float valves seemed to be like 1/32 longer, so I dont want to try and use them. And of course nothing comes with actual specs anymore, so I cant just buy by the measurement.
If I can at the very least get the brakes together and working properly, I should be able to putter around the neighborhood in a week or two. At that point, I think Ill see how much further and deeper I really want to go with this build.

 

[Bo82CB]

Most definitely replace brake lines!!! Why would you gamble with your safety just to save $200!?
Good work, just keep on and stay committed.

 

[macepatrick]

Well, she's complete.
Clutch is sticky and throttle is really slow. So I haven't really been able to take it for a ride yet. She's still stuck in the back yard, too. Waiting on help to get it through the house and out front where I can really take it for a ride.
Tach cable broke the other day, got a replacement coming in a few days.
Still very little rear brake pedal, gonna keep working on that.
Its been quite an adventure. I'll let y'all know when she gets taken out for a walk.

 

[Trkdrvr1376]

Congratulations
I am sure it’s exciting to take that first ride.
Good luck

 

[mrtwowheel]

Adjust the chain before adjusting brake pedal and stop light switch.

 

[macepatrick]

I finally got some miles on her!

Ok, literally "some" haha

Over the last two days the weather was nice enough and I had the free time so I warmed her up and took her around the neighborhood. Put a total of 7.9 miles on her and got it up to 30mph. No wobbles, or anything scary. Carbs definitely need synched, but I dont have the equipment. She was pretty reactive and spunky. just not happy at low idle.

The only things that really need work is possibly a new rear brake master, the carbs getting synched/ tuned, and some fresh dust boots for the front forks.
It wouldnt hurt to have a pro go over it, Im sure they would find things to improve.

But I have ultimately completed what I wanted to. My stepdads final project is reassembled and got a few miles on her.

Im gonna put it up in classifieds, but probably very mildly over priced. If no one wants it at the cost, maybe ill keep at slowly but surely over the winter. I just want to recover the few bucks I put into it for my part, but its really a fundraiser for my mother. Now that shes alone and should be retired, (but that doesnt even cover her medical), every little bit helps. I think since my stepdad originally put the money to buy it, then the profits should get returned to her (their) account anyway.

I appreciate all the feedback and advice and shared adventures. You all have been great! Ill be around, and if I keep it, I will keep the updates coming!! If I remember later, I will post a short vid of me putting on her first few tenths of a mile since being put back together.

 

[DEO]

I finally got some miles on her!

Ok, literally "some" haha

Over the last two days the weather was nice enough and I had the free time so I warmed her up and took her around the neighborhood. Put a total of 7.9 miles on her and got it up to 30mph. No wobbles, or anything scary. Carbs definitely need synched, but I dont have the equipment. She was pretty reactive and spunky. just not happy at low idle.

The only things that really need work is possibly a new rear brake master, the carbs getting synched/ tuned, and some fresh dust boots for the front forks.
It wouldnt hurt to have a pro go over it, Im sure they would find things to improve.

But I have ultimately completed what I wanted to. My stepdads final project is reassembled and got a few miles on her.

Im gonna put it up in classifieds, but probably very mildly over priced. If no one wants it at the cost, maybe ill keep at slowly but surely over the winter. I just want to recover the few bucks I put into it for my part, but its really a fundraiser for my mother. Now that shes alone and should be retired, (but that doesnt even cover her medical), every little bit helps. I think since my stepdad originally put the money to buy it, then the profits should get returned to her (their) account anyway.

I appreciate all the feedback and advice and shared adventures. You all have been great! Ill be around, and if I keep it, I will keep the updates coming!! If I remember later, I will post a short vid of me putting on her first few tenths of a mile since being put back together.

Good on you bro. You're a good son.