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  1. 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...
  2. K

    Full rebuild on 750a carbs question

    I had two extra sets of carbs that came with my 78 750a. They were all taken apart. So I am rebuilding a set. Now, The choke shafts I have a set that look zinc coated with plastic pieces that clip on the shaft. Then I have a set that are all silver and round all the way through with no...
  3. EMM

    Sold / Found / Inactive - 1979 DOHC CB750 Carburetors

    I rebuilt and bench synced these carburetors myself. I had them on my bike and running. I went through them and repaired/cleaned everything they needed. $$$? Open to any offers.
  4. J

    Altitude changing bike performance

    Hello all, I recently brought my all stock 1979 CB 750k from Illinois witch is at 700 foot elevation to out Colorado, 7200feet where I reside now. Obviously the bike is going to run rich but how rich? What I’m wondering is am I going to be forced to rejet it? (we all know how much of a pain in...
  5. 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...
  6. WhiteWidow


  7. 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...
  8. 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...
  9. K


    I have the repair manual for this bike. 78 CB750A but in the book it does not say how many turns out to start with the fuel screws. Shows how many for other models but not this one. Also, there is the solenoid attached to these carbs. Well, the two wires were cut and I cannot seem to find...
  10. S

    Clean out gas tank.

    Maybe just a repeat of something already posted but I found a pretty good way to clean out the gas tank on a well maintained machine. If the tank has been left for a long time and looks pretty bad inside, I can't help you. On a good machine put a little gas in or leave what fuel is in it already...
  11. Beasty

    Rejetting my Frankenbike...

    Several years ago, I purchased a box o'parts of a CB750 chopper (true chopper. '77 CB750F frame cut up to rake neck, forks for the 750F with 6" longer tubes). The engine it came with is a CB750K with a set of '77 CB750K Keihin Carbs. Had to do a complete rebuild of the Carbs as they were so...
  12. F

    1977 CB750F Super Sport Carburetor rebuild

    Hi there friends, new to the forum. Tried a quick search, couldn't find an existing topic. I bought a Super Sport a week ago for very little money, and it starts first time (kick) but runs fairly rough. It only really runs on choke, even when warmed up. I'm pretty sure the guy left gas in it...
  13. B

    Carb Suggestions - 81 CB750 w/ Drag Pipes

    Looking for some “expert” carburetor/exhaust advice for my 81 CB750. I know drag pipes going to kill some performance but I’m hoping to find a way for bike to run as well as possible with the pipes. From my reading on this forum and talking to Cycle X, it sounds like running the stock carbs is...
  14. 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...
  15. K

    Carburation, valves or compression?

    Good afternoon everyone. They would help me a lot if you try to help me with my problem. I have a 1982 CB750 KZ, RC01. The motorcycle was stopped for 25 years when I bought it. I restored everything I could myself, but I did not open the engine. I cleaned the carburetion myself, but the...
  16. B

    Gas Cap Lock

    Does anyone know of a place to get gas cap lock for a CB750K '81? Mine broke. Will Also entertain an entirely new gas tank as well. Thanks
  17. B

    Honda chopper frames

    What's a good website to look for honds chopper frames
  18. D

    Carb syncing question

    I have an 81 cb750k recently rebuilt the carbs bench synced them also put the gauges on it and it seemed close at the time and finally coming back to it after 3 month. So first question is would adjust the valve shims change my synchronization? And also would having them no perfectly synched...
  19. T

    Carburettor fuel measurement

    Hi all, My first post, unfortunately is a question rather than an answer. The short of it is - can anyone tell me the fuel measurement on a 1981 CB750K? To be clear its not the float height I am after, I know this is 15.5mm, its the amount of fuel this will set i.e. would this be on...
  20. Z

    1980 CB750 Runaway Idle

    Hey guys, I have a 1980 CB750k that I bought for very cheap as a project bike. This is my first bike so everything is new and a learning experience. So let's get to the point of why I am making this post (I've tried researching all over before making this post). Essentially I have got the bike...
  21. H

    78 hondamatic

    I have a 78 hondamatic 750 the bike didn't run when I got it.i redid the carbs set the floats cleaned the points I think the timing is good but all it will do is puff and backfire maybe a vacuum leak idk any ideas will be appreciated
  22. G

    1977 CB750F petcock?

    I'm looking for a replacement for my seeping petcock. I was wondering whether a petcock from another model Honda has been tried? The OEM unit is discontinued. thanks, Pat
  23. Bmb2492

    750 Nighthawk Gas tank

    I have a '82 750 nighthawk The gas tank was rusted and the previous owner tried to line it and it didn't go well. I tried to get it sandblasted and it exposed a ton of pinholes. Where could I find a tank? I haven't found any online. I'm pretty sure nothing will interchange. How would I even go...
  24. NoIdeaWhatImDoing

    '82 CB750SC / Difficult Starting & rough idle

    Hello All, ...Its important to state for the record that i am not an experienced motorcycle mechanic... 82 cb750SC NH. Got the bike free from a friend. It sat in his garage for a year-ish. He cleaned up the carbs but didn't rebuild them. When I hauled it to my house, it wasn't running, carbs...
  25. Bmb2492

    750 Nighthawk

    I bought an 82 cb750 nighthawk with 4,487 miles on it for $300. Hadn't been tagged since 03 so probably never had ethanol ran through it. Replaced the battery and spark plugs and it tries to idle with the choke on. Should I rebuild the carbs or just clean them? Any ideas that might help. I'm...
  26. S

    Uni NU-4046 In Stock Airbox -- Any Jet Changes Needed?

    Hey folks, got a question regarding a stock replacement oiled foam filter: the UNI NU-4046. Couldn't find any threads on it in this forum. This is for a buddy's 1980 CB750F, which has already been rendered not-original by multiple previous owners. It currently has a set of horrible cheap pod...
  27. Butscut

    CB750F 1982 Carb spacing / Inlet boot issue

    Hi folks, I'm currently restoring a 1982 CB750F Supersport and having now rebuilt the engine I am test fitting a new set of Mikuni carbs and found and have run into an issue. From memory the carb spacing of the OEM KeiHin carbs (now sold) was 80-100-80 at the inlet of the rubber boots. As these...
  28. T

    vacuum lines

    hey guys, my buddy recently got a 1995 cb750 nighthawk and we've been able to start it on starter fluid, I've taken the petcock apart and cleaned it 3 times. it looked like the vacuum lines weren't connected fully and i don't know exactly how to make them right. any help or advice?
  29. Luis Etchenique

    CARBS / drain lines

    question -- Do the carbs' drain lines have to be in place during the motorcycle's normal operation ? or ... can I just connect them when/if I need to drain the carbs ? I ask this because I just rebuilt my CB750F SS DOHC ( as a race replica ) with pod filters, and I want to keep the engine as...
  30. Luis Etchenique

    SOS -- fuel line

    hello all -- having a time trying to install my fuel line ( fuel tank to carbs ) on my freshly rebuilt '79 Super Sport 1 ) the petcock's outlet in in a very tight spot, AND it faces the center of the bike 2 ) so to connect to carbs inlet, it has to perform a tight right-hand turn and then...