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  1. JMC

    Introduction - 1981 CB750K

    Hello Fellow Wrenchers, I just wanted to introduce myself. I'm sure I will be picking everyone's brains/experience here as I work on my most recent project. I have restored 2 Yamaha QT 50's ('79 and '80), fought with a 1978 Sachs Balboa, and recently picked up a 1981 CB750K (for $90!!!) from...
  2. W

    CB 750 build

    I am looking for connecting rods from a CB 1000 to go onto my 900 crank I will also need carbon and exhaust recommendations for an 1100 F if anyone knows where i get such parts.
  3. W

    Cb750 build

    I have a CB 900 crank to put into my 750, I am looking for 1981 CB 1000 custom connecting rods if anyone knows where I can find them. Also I will be in need of carbs and an exhaust for an 1100f if anyone has any recommendations
  4. T

    Advice on Rear Fairing Fab

    Hey all, this is my first post so I appreciate any advice that helps. I have a 1980 cb750f that I'm doing a full cafe build on. I've been looking into different tail options and although I like a lot of options out there I'd love to try and use the stock rear tail and integrate it into my new...
  5. W

    Cb750/900 build

    i have a 1980 dohc cb750 that needs all new gaskets and seals. I build national championship winning dirtbike motors but have never touched one of these motors before so it is a bit of a learning experience for me. I have read in multiple places that a cb900 crank and top end will fit my bike...
  6. W

    DOHC 1980 cb750

    As stated in the title i have a 1980 cb750 with dual cams, i recently purchased the bike with unknown miles and have very little knowledge of these bikes. It has pod filters and was tuned for them, the left side breather hose had a plug in it which is something i will fix but i am having a few...
  7. deeveeance

    Almost done with project 1982 CB750C, looking for final elements/advice

    At the end of 2021, I traded an unused Macbook Air for a decent 1982 CB750C with title and all, got it registered under my name and off to the races. I went through some carb trouble, fought drivetrain elements, and, everyone's favorite, electrical gremlins. Summer of 2022, I slapped on a new...
  8. WhiteWidow

    Fork Oil - capacity's & type

    Having issues when braking, I feel a CHUG/VOID in compression of fork when braking. Looking @ the factory specs. I noticed oil type is not shown. I've heard that heavy viscosity automotive oils can be used. I've also noticed on this chart that the amount of oil varies from assembly to...
  9. J

    High altitude jetting

    Hello all, Ill keep this simple, moved from 500 foot elevation to 7200 feet. Bike is running really rich now due to thinner air. I would like to fix that problem. Most riding will be done between 6000-7000 feet i should note. I have all stock setup with 105/70 jets. Bikes a 1979 Cb750K What...
  10. thughes0025

    Getting some speed out of a 81 cb750c

    I'm new to this style bike had a 05 R6 for many years now I know the 81 cb750c isn't even close the same but I would think 60mph an tacking 5,000 rpm is a bit hard on her...ol'girl runs like a top just seams she's reving extra high on highway...umm was thinking sprocket change would help just...
  11. R

    Primary chain loose. chain from crank to primary shaft CB 900F

    Hi, I have a 1982 CB 900F and I need some help with it. I had finished building the engine and everything seemed to be perfect. However, when I accelerated, the primary chain (the chain from the crank to the gearbox) slipped. I opened the gearbox and found that the chain was loose and had...
  12. K

    30 amp fuse pops when key turned “on”

    Hi all, The problem started after the bike was dropped. Now the main 30 amp fuse pops whenever the key is turned to the “on” position. I replaced the wiring harness and managed to get the bike to turn over a couple times before the main fuse popped again. My battery cables don’t seem to be...
  13. A

    81 DOHC Rebuild- anyone know what this part is

    Doing my first engine rebuild and while I was tearing down the motor, working on getting the crankcases separated (I think) I had the motor on its side and this guy fell onto my worktop. Not sure what it is our where it came from. Any thoughts?
  14. popsycle

    Physical Exam just became an autopsy!

    I have been examining the motor on a CB750K (1981) with an eye to getting it to run. It's a bike that was left in a storage locker with a license plate that expired in 2001. I found the electrics had a dead short and other apparent issues but today I did a "thumb" test and found no compression...
  15. S

    Fuel level sensor

    I have a beautiful 1982 CB 750 SCA Nighthawk. Need the fuel level sensor for the tank (fuel gauge device). Any sources for it? Also the Nighthawk emblems off the side covers. Please help! It’s a true time capsule found in a storage locker, wanna do it right. Needs the proper color to be correct too
  16. S

    Pulse generator wire connecter has gunk in it and how to check it

    1982 cb750c custom I’m trying to check the resistance of the pulse gen at the connecter site and a there is some grease in here is this normal? And b I don’t know which wires to be checking together and for what measurement? Any help is appreciated.
  17. R

    Hanging Idle But Seems Rich

    Hello, I just acquired a 1981 cb750 that I am trying to get running as the wife's first bike. I can get it to stay running but it idles very high. Cold starting on choke everything seems fine until the choke is off then it stalls unless given throttle. However if given throttle it has a hanging...
  18. J

    Steering lock

    Hello all, I got a 1979 Honda CB 750k (Fancy-schmancy 10th anniversary edition) Anyway i’ve never been able to get the steering lock to work properly. Essentially I turn the wheel all the way to the left press down on the key and attempt to turn it to the lock position and it just does not...
  19. D

    Brake Caliper Seals

    Good day, I'm new on here, but not new to bikes and have worked a fair bit on Honda CBs. I have an 82 CB900F in the garage at the moment. Pretty much a rebuild as it hasn't ran since 08. I took the calipers apart and cleaned them and bought new seals from the Honda dealer. The kits were from...
  20. S

    Unknown part name and it’s functionality.

    I have never worked on a motorcycle before, never mind a carbureted engine. A friend of mine gave me a bike he planned on fixing but was just going to scrap because he gave up. I put fuel in the tank of this old 82 750SC and the fuel wasn’t getting through the lines of this diaphragm part thing...
  21. A

    Lwr Case - Is this a crack?

    Just inspecting and saw this. Not sure if this is a crack. Nothing is visible from the inside of the case. So not sure what’s going on here if if it is any concern.
  22. N

    Carburettor reaper kit

    Hi everyone this is my first post and was hoping someone mite be able to help me . I have a 1982 cb 750 that I’ve taken the carburettors off and trying to rebuild them but I’m struggling to find the right reaper kit . The make of carburettor is Keihin and the number is 52ADTA but nobody has this...
  23. A

    Main Bearing Look

    Tearing down my first engine and wanted to get some seasoned eyes on my main bearings. They look good to reuse? I am Picking up some plastigage so I know that will be the determining factor but just asking if The old ones pass the eye test.
  24. S

    What is this thing called I need to find a new bolt for it.

    I’m getting frustrated because everything I try to search to find the bolt size is showing me the wrong stuff.
  25. W

    Spoke rims to Comstar swap

    I'm thinking about buying Comstar rims for my 1980 Honda CB750K, it currently has spoke rims. Has anyone done this? I trying to figure out if Comstar rims from a CB750C would fit. My plan would be to paint the rims gold. I've seen some gold Comstar rims for sale already but they are selling for...
  26. S

    Lowering bike height for shorter rider

    Hi I have a 1982 custom and I am trying to lower it about an inch so that I can walk the bike easier. I’m 5’4. I am aware I probably need to go aftermarket but if I can lower it without that would be great. Any help appreciated.
  27. A

    New Main Bearings

    Rebuilding engine on my 81 750. I know I have seen posts on here from amc about the "hard/expensive" to get main bearings for the DOHC. On Partzilla they are $17.50 EACH. Is that accurate that I am going to shell out $180+ on main bearings? Any places you know where I can purchase them from...
  28. A

    Opinions and Suggestions

    Hey all been lurking and reading a ton on here as of late. I’ll skip the long intro (another thread)and cut to it. Picked up an 81 CB750 for a few bucks with the goal of just learning about motorcycles and engines. (Zero prior experience). no real hard goals other than that. Started with an...
  29. W

    Fresh Paint Job

    I just got my tank and side covers back from the paint shop. The bike was black when I bought it. I had it repainted Candy Imperial Blue and decals added. I paid $241.50 for the paint and clear coat through https://www.rsbikepaint.com. And purchased the decals from...
  30. H

    Wanted - 1980 CB750K DOHC vb42 carb - outer right, number 4 cylinder

    Hi all, I have been getting a slow leak on the outer right, no 4 cylinder carb for a few weeks now. Investigation has led me to find that the alloy body is cracked and it looks like I need a replacement carb body. Does anyone have one ? Or a complete bank and I can strip etc ? I am in the UK and...