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TheProtoSmith

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About TheProtoSmith

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  • Location
    Denver
  • Cars
    1976 land cruiser (full resto in progress), 1984.5 Nissan 720 4x4 king cab (barn find), 2015 Crosstr
  • Interests
    Onewheel, cars and restoration, technology and design, skiing, mountain biking, video games, teachin

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  1. ok Cool so i think i found generic motorcycle carb jets. that are metric which should line up with it being a japanese carb. but they are for like 150cc motors so i'm a bit confused on that. unless i'm mistaken (because i haven't been able to take the carb apart today. it should be an M5. x .8 thread with a #100 diameter nozzle. although i might just run it even leaner than that given my insane numbers. also thinking of dialing back the pilot too to probably be the 107 instead of the larger bore. But thats just a thought right now. Ill lay off from drilling out the plug and see if i can get there with the jets if these parts look right some sort of confirmation would be great. Cheers, Smith https://www.amazon.com/gp/product/B07JZM493B/ref=crt_ewc_img_huc_2?ie=UTF8&psc=1&smid=A23MTL1LIY6YXM https://www.amazon.com/gp/product/B07SL2JH4T/ref=crt_ewc_img_dp_1?ie=UTF8&psc=1&smid=AAQI0AA583SPQ
  2. Any chance I can get a link? I don't do motorcycles but I'm sure there are different types of jets. It seems to really match the diagrams of the carb in my service manual . I just think it's missing the window but I'm no expert. Could also be a fully rebuilt ebay one. I opened the top off the carb and it def has something that interfaces with valve at the bottom
  3. Ok so continuing to dig I was able to find the fuel air mix solenoid. But it's behind a Welch plug. I plan to drill that out and adjust it tomorrow. Hopefully that will offer me more options in terms of tuning... Any one say that this is a terrible idea? It's this part even adjustable? Diagrams are not as detailed as I would like. If it's not electrically controlled how is this actuated?
  4. So I just failed again, but it's the lowest scores across the board that I have gotten which is a win. Down to 130's in CO. The test shows that it's great during decel and horrible during acceleration leading me to think a new jet would be helpful but confirming my fears of having way too much fuel entering the system.
  5. It's this https://www.oreillyauto.com/detail/b/tomco-5051/fuel---emissions-16775/carburetors---parts-16801/carburetor-12234/840def96ca83/tomco-hitachi-2bbl-carburetor/10096/4746383/1984/nissan/720-pickup#WAR Without the glass panel
  6. My carb doesn't have a window. I spose i could add in a piece of glass if i try hard enough. but without that is there no way to tune?
  7. Thats what i was thinking. My tach is dead. i tried reflowing the board but wasn't able to get anything out of it so i'll pick up a photo tach later today and get a reading off of that. is there a good way to tune the float level when you don't have the window? (something like tighten the screw all the way then back off 1.5 turns)
  8. So i've been thinking and now i'm curious if my float bowl height might be too high. I don't have a viewer but it could explain the constant over rich condition right.
  9. So it looks like the only wires I have coming off the carb are the 2 wire Fuel Shut off solenoid and the Electric Thermal Choke. Also didn't see any connectors floating around back there
  10. Yeah I'm definitely adjusting that one. That the screw driver is sitting in. On my rebuilt carb there was no plug. It's the lower one right? I'll have to check on o2 sensor in the morning. Also just found the ECU which po told me was not part of car.
  11. Ok so problem was the fuel solenoid vacuum switch was caught in a feed back loop. After adjusting boost control it was solved. Switched out all the vac lines and am confident they are right. Switched out cap and rotor plugs and wires and definitely big improvements for rough idle I had before. I still feel like I'm running rich even with the idle mix screw all the way in. I read that there is another part that controls the mix but all the manual said was to have the dealer do this. What should I be looking for next? Datsun Mike grace me with your vast wisdom 🙂
  12. hmmm ok thanks for the info! any ideas on why i might be surging?
  13. OK so did a lot of digging and testing, (only sucked up a little bit of gas) Boste control unit was jammed shut, rebuilt and now the vacuum control appropriately turns on the rest of the vac system and turns on the secondary ignition control. But now the engine has a hard time maintaining steady idle. I think its the TVV (the 3 port temp controlled vac valve) when the car is warm its supposed to send vacuum from the air filter and the Alittude compensation system however there is no vac there. Does this conceptual model line up with surging at Idle. Car is also still running rich. but now there is actually an effect when I do adjustments. (choke system is working as well as fuel shut off, No dieseling on shut off) Any thoughts? also Datsun mike. You were right those aren't Vac Release valves they are sensors. Both seem to live in the Normally open state Front one controls fuel (i think) and back one controls secondary coil. Boost control valve was easy to build from inspecting here is what I think its operations are: When Under normal load -> Convert Vacuum from about 20 mg of merc to about 10 (this can be adjusted by tightening or loosening the back nut with the clip spring) with a variable vac relief valve that pulls from atmosphere When Under heavy load, Open and disables secondary coil and Gets rid of vacuum advance (I think, haven't been able to observe because i'm only a one man team) to prevent early detonation. When Under No or negative load, Close and Deprive system from vac, turn on fuel shut off system, create a vacuum advance to burn extra fuel, and turn on secondary coil for these systems to work clutch and transmission neutral detection must be operation or they will force the open state of system, Ie secondary coil stays on during heavy load inducing early detonation and excessive heat. feel free to poke any holes in these theories
  14. If they are the same switch on different ciruits then moving the vac line should have the same result as switching the electrical connection.. the vac source doesn't change. Unless I'm mistaken those are vac release actuators.
  15. Datsun Mike I'm confused I switched the vac tube over to the other switch, same result. I'm thinking that there is something else wrong, and that this is a symptom. The only place I can get vacuum is straight off the intake manifold and off the middle passenger side ports on the carb from what I've read of the electrical diagrams, the secondary ignition coil is available when the car is in gear or the clutch switch is released . Why would they also vacuum control it? Why would they design the coils to both fire when only in neutral, wouldn't you also want a faster and more complete burn all the time? This 720 is making my brain hurt. But again thank you so much for all your wisdom and guidance, you are appreciated
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