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This is a discussion on Hello everyone within the NEW MEMBERS READ HERE! forums, part of the Caferacer.net Forums category; So I cleaned the rotor rings. First I took a scotch brite pad to it, and then i polished them to something close to a ...

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  1. #31
    Junior Member 46lukasz's Avatar
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    So I cleaned the rotor rings. First I took a scotch brite pad to it, and then i polished them to something close to a mirror finish.










    I also had a look at the stator 6 pin connection and it wasn't bad. no visible corrosion of horrible levels. I still took a small wire brush on a dremel tool and cleaned the contacts well.


    I finally have the bar ends installed on the bike. They are custom and my own design. My friends from work dad turned them for me on a lathe. They are solid steel so quite heavy. First picture is a 3d render of the design which was then 3D printed to see what it would actually look like on the bike. Then I painted the actual ones gloss black to match the grips.












    I also have yet another indicator relay since I was not happy with the quality of the last one and it was working when it wanted and now when I wanted it to work.
    This new one needed to be grounded so I first tested it by connecting the ground terminal to the frame and it worked.
    Then I remembered that these bikes have a green wire near the indicator relay connectors, that is not used for anything. I checked the schematics in the book and it looked like this unused connection was going to the regulator.
    I also checked its continuity and it turned out that there is an electrical connection between this unused wire and the frame. So i plugged the new relay to this unused connector and it works.



    I hope it wont burn.

    I also installed new spark plug caps and red ignition cables so that everything on there is nice and fresh. With the old setup, one of the 4 cables was different than the rest and it was giving me trouble when the cables were moved by hand so the connection wasn't solid. It is now.













    Kind regards,
    Lukasz

  2. #32
    Junior Member 46lukasz's Avatar
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    Hi again guys,

    I have extracted the connectors from their plastic housing on both the male and female side of the alternator plug and cleaned them up with a wire brush on a dremel tool.
    The female connectors were not that bad, I also compressed them with pliers to make them a tighter fit. The male spade connectors though were very dirty and the wire brush made a massive difference visually.

    I also took a picture of the polished rotor rings after some idle time of the engine. Not bad in my opinion. The brushes on the stator are also well above their indicated wear lines. The rotor resistance measured 5 Ohms so its good as well.

    I retook the reading at the battery with engine idling and this time with no lights on or anything and it was spot on 14.4V.
    With engine was revved it was no higher than about 15V so that would indicate the regulator works fine too.











    I also installed the new rear pegs. They look much nicer than the original bulky rubber ones.
    They have a spring loaded ball bearing that clicks into notches on a plate I had to weld in so that they can be adjusted to fold up or down.
    I also had to make a small cut in the mounting bracket so that they fold down all the way horizontally and rest on the bracket then. Other than that it was an easy job.







    I finally balanced the carbs. I bought the gauges from Alpha Moto and they have really nice adjustable dampeners so that the needle doesn't jump around.
    I got it fairly spot on, maybe the 4th cylinder is not perfect but I am really happy with myself especially when I didn't have a proper tool to turn the lock nut without also turning the balancing screw at the same time.
    I made one out of an old socket so I could put a flathead screwdriver through it.
    I also swapped the blanking bolts from the Japanese standard Phillips head look-alike to SS Allen head and threw in new copper washers as well

    Video of it linked at the bottom











    I think I will have to change the throttle cables for new ones because I noticed that my throttle was sticking open, and when I undid the adjustments screws on the carbs side it suddenly fixed itself.
    The old cables are also kinked on the handlebar side.

    I will also look into getting a new tacho cable to go with the new speedo cable. The indicated RPMs are quite jumpy especially at low RPMs.
    I suspect I will also have to change the seal that is between the tacho cable and the head cover because I noticed a small leak there.


    Question:


    I recently noticed that once the engine warms up and is taken off choke, it runs really well, BUT...
    Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
    You can kind of see this happening on the carb balancing video linked above
    Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.




    Kind regards,
    Lukasz
    Last edited by 46lukasz; 03-25-2019 at 01:25 PM.

  3. #33
    Senior Member CaTacL1sm's Avatar
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    Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
    You can kind of see this happening on the carb balancing video linked above
    Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.
    I might be completely wrong, but assuming your carbs are balanced, your idle circuit may be too lean. When you cut the throttle, the sudden switch to the idle circuit causes a lack of fuel and kills the bike.
    Quote Originally Posted by alwhite00 View Post
    Fuck all of you guys. Get into your little circle jerk and have fun. Thought this may be a pretty cool message board but damn, you guys are assholes.

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  5. #34
    Senior Member TrialsRider's Avatar
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    Quote Originally Posted by 46lukasz View Post
    ...
    I recently noticed that once the engine warms up and is taken off choke, it runs really well, BUT...
    Once you give it a twist of the throttle the RPMs climb up nicely, however on their way down they go way below the normal idle speed and the engine can die if not let off the RPMs gently.
    You can kind of see this happening on the carb balancing video linked above
    Any ideas what might be causing that? I think it has something to do with idle jets, but I also think that it needs a good proper thrashing which it didn't get basically since I bought it.

    Kind regards,
    Lukasz
    CV carbs are a pain in the ass.
    If your float levels are off that could induce the problem you described, unfortunately several other CV fuel circuit issues may also be the cause of the problem including fuel delivery pressure.

    #2 carburetor probably has some kind of fuel pump thingy on it yes? That could be an accelerator pump or it could be a decelerator fuel pump. You might want to research that part because it seems to me they added a decelerator pump to some motors to deal with over-lean operating conditions when the throttle is chopped.

    You have to remember that on a CV carb your throttle cable controls a butterfly valve but that valve precedes the vacuum operated slide valve. By design there is a lag time between the operation of the butterfly valve and response to open the slide valve. On closing the throttle both valves slam shut very effectively, fuel circuits were added to the design of later CV carbs to accommodate that operating condition, your carbs could have as many as 5 fuel circuits to control air and fuel ratios throughout normal operating conditions, blockage in any of those tiny passages is a common problem.

    Last edited by TrialsRider; 03-26-2019 at 06:57 AM.

  6. #35
    Senior Member CaTacL1sm's Avatar
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    I'd just get some CR smoothbores and be done with it
    TrialsRider likes this.
    Quote Originally Posted by alwhite00 View Post
    Fuck all of you guys. Get into your little circle jerk and have fun. Thought this may be a pretty cool message board but damn, you guys are assholes.

  7. #36
    Junior Member 46lukasz's Avatar
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    Hi guys,

    A little bit happened since the last update:

    Shortly after balancing the carbs I noticed that the throttle is sticking open, so I replaced the push pull throttle cables with new ones.
    One of the old ones had a kink in it and it was causing the problem. I lubed the new cables nicely put some grease on the bars underneath the throttle tube.
    I also got a new tachometer cable just because.

    It was a very noticeable improvement, throttle was very smooth, and after adjusting the idle speed slightly I could take the bike off choke in about 20 seconds so that was great.

    I started playing with carbon fibre and epoxy resin, just out of curiosity of how you work with this stuff. It comes out really nice and i might do something cool for the bike soon.





    I'm also slowly buying/preparing equipment to repaint the bike.
    I plan to go for deep metallic black with a red stripe running down the middle.
    There will be a chrome-looking Honda sticker with the wings on the tank, and a red CB750F on the side cover.
    The side cover stickers I got are reflective stickers, i don't know if its a good or a bad thing yet, but i like them.
    I did a mock up on the computer just to see how it would look in black (just inverted colors) and I am happy with it.







    So I was really happy, bike running best I ever saw it run, just the paint job and the project is complete, but then disaster struck!
    I fired the bike up and noticed that fuel is pissing out of one of the overflow tubes at the carbs. Small tear-down to take out the bank of carbs with the airbox.





    I also noticed that the fitting at the top of the airbox which is the input of the crankcase ventilation system has this yellow goo on it. What could that mean?



    I took off the float bowls, and saw that they are really quite clean on the inside. No fuel turned into varnish anyway!





    With the carbs and float bowls off, I poured some fuel into the input tube, and tested the float valves individually, by keeping 3 closed and opening one at a time by hand.
    None of them was leaking! So I'm not sure what was going on (maybe one stuck open). I guess it works as expected and it would be fine now if i threw it back on the bike.
    One other thing I'm going to check though is maybe one of the overflow tubes that stick up in the bowl is cracked along the sides or at the bottom. If that's the case then the fuel doesn't have to reach the top of the tube to go into overflow.





    And because its taken off now I thought I might as well take some time and clean it up a bit later. Any tips on this?


    I was quite surprised to see that there is no diaphragm underneath the top caps of the carbs. Instead, they use a metal puck and very tight tolerance to make a seal and work in the same way as a diaphragm (vacuum created on intake pulls the puck with the needle up etc).

    I have a couple of questions:

    1. Should I use some lubricant between the puck top ring and the inside of the top cap to make a better seal? Maybe polish the two surfaces?


    2. Should I also use some lubricant on the slides that go up and down inside the throats? There seems to be a lot of rubbing action there, and the slides of carbs 1 and 4 have visible scoring marks on engine side. 2 and 3 are very smooth


    3. Could someone explain what's the function of the air cut-off diaphragm? there is one on each carb.


    4. I totally don't have an accelerator pump on the #2 carb. I also cant see an accelerator nozzle anywhere in the throat of the carb. I thought these bikes came with one. Is this normal?




    Thanks!
    -Lukasz

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