1. Neverfinished

    No vacuum on cylinders 3&4

    Bike runs, idles steady. Carbs have been pulled and gone through twice. Manifolds on both sides replaced. No indication that the bike is running on only two cylinders and it actually sounds nice at idle. Figured since I got it running fairly well id do a carb sync. Cyl 1&2 look good - both...
  2. Cafe Customs

    79 cb750 Dohc issue idling

    My uncle has a few cb750 cafe racers and we have been working on getting her at a steady idle and to rev appropriately it's running on choke and only for a limited time he has changed multiple carbs have tried different afr have good spark going to the plugs changed the cdis multiple times and...
  3. T

    1980 CB750F Oil light On/High and Erratic Idle

    Hey Guys looking at for some insight on some issues that I am having with the bike I just bought. So I bought the bike running took it for a spin upon purchasing it runs great the idle does sit high at 2,000 RPM when warm. The bike does not idle when cold, the bike starts right up though but I...
  4. N

    1980 Cb750c counter shaft seal

    Hey everyone, I’ve got a 1980 cb750c dohc. I recent rebuilt the top end of it, minus a few seals, but I made the mistake of trying to change the counter shaft seal once the motor was together, major mistake in my part. I totally messed it up, and to get the new one in you need to crack the case...
  5. R

    Sideways play in front drive sprocket (normal???)

    I have been rebuilding a 1979 CB750 engine for some time now (on and off). Since it had been so long since I took my engine apart, I decide to do a mock assembly of my crankcase before I close the crankcase up for good! Everything seems to be fitting well and turning/working as intended (and...
  6. P

    Another Fork Seal thread - 1981 CB750K DOHC

    I've had some bad luck with one of my fork seals consistently leaking and wanted to get the opinion of others. Take a look at the following pictures and please let me know if anything obvious stands out that could potentially cause a fork to leak: I feel like the problem likely has to do with...
  7. deeveeance

    Wanted - 1982 CB750C compatible carbs (possibly borrow?)

    Need some carbs to fully test out my project 1982 CB750C (DOHC) before committing to buy a set of Murray's Carbs (Mikuni VM34's) or Dynoman's Keihin CR31's. Open to anything compatible, not sure what the market is for the OEM-Alternatives is. If you happen to have a spare set that you don't...
  8. B

    Carbon build up question

    Hello everyone, I'm in the process of rebuilding my first engine and was wondering how you guys remove the carbon build up on/around the valves ( if its even necessary to remove all of it ). I don't want to be too rough as I know these parts are delicate for clearances, especially around the...
  9. B

    Honda CB 750 Custom Rattling Engine Noise

    Hello I have a restored Honda CB 750 Custom from 1981. The motorcycle has undergone a major renovation. Chains with tensioners, pistone rings, valve seals, pans and bushings have been replaced in the engine. The problem is that when I start the motorcycle on the choke, even on warm days, for...
  10. A

    CB750 RC42 stem specs?

    Can anyone help me with this info please? Stem lengths measured from the bottom washer under the race and seal: Total= ?? To bottom of top threads = ?? To top of threads for load nut = ?? To bottom of threads for load nut = ?? I´m currently working on a project and need this info, thanks
  11. K

    Loss of power at ignition switch

    I just bought a 1982 CB750SC. It started and ran fine when I bought it. Brought it home and it stalled after running 10 mins or so, with loss off power with the ignition switch on. After 20 mins it would just came back. It has done this about 3-4 times. New, battery, new igintion switch. Don't...
  12. K

    New member with caliper question

    Hi everyone, I've a 1979 Honda cb750 kz that I've had in storage for about 8 years and I'm finally getting round to getting it back on the road. Its in pretty good condition but when I bought it didn't have the front brake calipers on so after getting them out the box of bits I've noticed the...
  13. B

    Opinions on Murray's Carbs?

    New to the bike world. Carb cleaning is a giant pain in the ass, especially for someone who's never before touched a carb. I am thinking about getting a set of Murray's Carbs. Any opinions? Should I or shouldn't I? I pretty much have my mind made up already, figured i'd just throw this up here...
  14. K

    New Member - CBX750 Project

    Hello, My Name is Kristian from the UK. I picked up a CBX750 back in October 2020 and now have a full on project on my hands! Plan is to build a 80's "GP Bike" with some modern touches... Anyway, enough with the writing. Here are some pictures... So far the current spec list is: CBX750F...
  15. cbxjon3

    cbx750 fuel tank 1984

    hi to the group, I am looking to buy a fuel tank for this bike. A 1984-1986 cbx750f.
  16. Luis Etchenique

    '79 CB750F super sport / DOHC -- replacement rear brake master cylinder

    hello CB750 friends - in the proces of resto-modifying ( into a race replica ) my CB750F s/s, like most of the bike ... the rear brake's master cylinder is completely gone -- I had to cut it off from the footpeg brackets, since it was welded by years of galvanic corrosion so my question is...
  17. S

    1981 cb750k parts interchangeable with cb900

    hello in australia needing help with knowing what parts from a cb900 will fit a 1981 cb750k, just got myself an excop bike complete in rough shape from sitting for 4 years but it runs, needs tune . biggest problem is the 4 into 4 mufflers a trash, eaten through, looking for replacement that...
  18. V

    Do not open cap

    1995 Nighthawk CB750. There is a black cap on the lower left side that says Do Not Open. What is it for?
  19. S

    First bike problems, Please Help!

    Hey guys, i recently bought a 1982 cb750k and have been getting it ready for this season. i have been experiencing a few issues that i don't know what could be causing them. the first issue I'm having is that when I'm heating up the bike the idle starts to run away and get up to around 4k rpm if...
  20. C

    Reg/rec, LifePO4 problems

    Hi guys! Pretty new on this forum! I have a couple of questions regarding the charging system/regulator/LIFEPO4 battery. - I am currently building a CB750 K(z) 1979 with an M-unit and all LED lights I bought a Ultrabatt Multimighty 12200M+ 150CCA and connected this in...
  21. S

    headstock grease washers

    grease retaining washer hi all new member here got a 83 cb750 f2d has anyone got any idea where i can get the grease retaining washer used in the headstock from and also the locking tab washer at top of headstock cheers
  22. L

    Broken carb part on 1980 Honda CB750C

    hey i am looking for some insight on how to solve a problem on my carbs for my 1980 honda cb750c. One of the prongs to hold my throttle cable broke right off and I cant find a replacement part for this. Not sure if i should try and get it welded back on or if there is a way i can get it...
  23. B

    Starter Solenoid Help

    Hi all, I'm rewiring my '81 CB750C. I just got to the starter solenoid, which I assume is the original, OEM unit. I see the 4 male connectors go to the reg/rec, starter switch, ignition switch, and clutch diode but I'm unable to find out which one is which. Is there a way to test them? Does...
  24. M

    1984 nighthawk 650 4-1 exhaust options?

    not alot of aftermarket exhaust options for the nighthawk dohc 650 ive done some research but some say its the same as the cb500 exhaust and some say the cb750 exhaust will fit will all DOHC models fit? Looking for a 4-1 exhaust
  25. J

    Gas Tank Swap

    Hello all New to this group and thanks for having me. I am sure this question has been asked before but here goes. I have a 1981 CB750C DOHC project and I am not in love with the stock tank. I like the CB750K and CB750F tanks but I am not sure the fitment will work. Does anyone know what my...
  26. P

    vague valve clearances

    Hey Guys, I finally got around and started the valve clearance job. But here comes a vague situation. I got a micrometer and also a feeler gauge. When i measure the feeler gauge with the micrometer it gets to the appropriate measurement( so 0,05mm is 0,05mm+-0,01mm) I started measuring my...
  27. K

    swinging arm

    does anyone know the distance between the swinging arm forks where the spindle fits on a cb750fz or any 1979 to 80ish bike, I have a problem now I have changed the wheel bearings and I am left with a large gap that wasn't there . but this is an old metmachex arm I and can't remember if there...
  28. M

    79 CB750L plan of attack

    OK, after getting a grounding issue and buying a decent set of jumper cables, I was able to do the compression test on my newly acquired 79 CB750L. Figured I'd move this over to the engine forum since electrical issues are sorted. After seeing the compression test results, I'm wondering if I...
  29. U

    84 CB700SC and the CB750SC differences

    I was wondering if there was any major differences between the two models. As I understand it the 700SC was for the US because of something to do with Harley not allowing bikes to be larger than 700cc. In Canada however they did sell the 750cc version? I'm shopping for a complete gasket kit...
  30. M

    79 CB750 Starter issue?

    Hello, just brought home a 79 CB750L project. Bike is partially together and was able to get it running with some jumper cables and starter fluid at the previous owners place before making the purchase. Once i got it home, i tried again as i wanted to do a compression test. Yeah, i know, should...