Project Hakosuka: .Oops. Hit a snag.


Where we left things in the last instalment was that I’d made some attempts to learn to tune the Webers, a task made somewhat harder by the discovery that the engine might be in a somewhat more hardcore level of tune that I’d bargained for.

But for the first time in weeks the Hakosuka came down off the axle stands, and at least it looks good (even if it doesn’t go)!

First I had another go at the carbs, and actually got a pretty decent result after a bit of experimentation. Basically what you do, is adjust the low-rpm mixtures until you optimise them (listen for the point where the idle is highest).


Then you use this device to measure the amount of airflow going into each carb. There’s a plastic cone at the end of the white tube, and when you stick it in the carb airhorn, a little pellet rises up that orange tube. The higher it goes, the greater the airflow. You adjust the idle speed screws on the carbs until the airflow is all the same.


The result was this:

As you can see, it’s reasonably smooth, but the idle’s a bit fast, it’s a bit slow to return to idle when revved, and when you shut it off, it runs on (called dieseling) somewhat. What I think I did wrong was set the idle speed with the linkages attached. I’d loosened the linkage arms on the main throttle jackshaft (so that adjusting one carb wouldn’t affect the others) but I think the weight or stiction of the heim joints of the linkages were holding the throttles of one carb open a hair….and so when I adjusted the other carbs to match it, it all ended up too fast.

And also I think the main return spring for the throttle linkage was too weak, and not forcing the carbs closed properly. So I decided to tighten the spring tension when PA-TING! The spring retaining bolt broke! Ahh well…easy enough to get a new one.


Oh, by the way, before I tuned the car last I replaced the distributor cap and rotor:


I guess it’s one of those things…on new cars with cam angle sensors and coil on plug ignition, these parts don’t exist. I’d just forgottten that on old cars these are regular maintenance items. Replacing the worn old ones made a big difference in smoothness:


But since the engine was warmed up I did an oil change, and one of the goodies I discovered was this extended sump. It holds 8L, which means that an oil change involves two cans of oil and two drain pans!


But remember that wobbly throttle pedal? I’d made an attempt to fix it but it was still a tiny bit wobbly. So I made a bridge: a short strip of thick steel to bridge over the uneven firewall surface and provide a flat surface for the pedal to bolt to. Success! It’s rock solid now.


The brake mastercyl arrived too. Chatswood Brake and Clutch bored it out and inserted a stainless steel sleeve, then fitted new modern seals (which required some machining). Expensive but worth it, the brakes feel good. One unique feature of the Hako mastercyl however is that you have to bleed the master cylinder after installation. Weird.


So far, we’d done pretty ok. I’d broken a component on the carb linkage, but it was easy enough to source a new one, the car now had brakes, and I was looking forward to having another go at tuning the carbs. I had a couple of days to wait for the new part to come in, so I decided to have a look over the electrics.

…and that’s when we hit a snag.

First, the headlights didn’t work. So I start at the beginning, and trace the +ve wire from the battery to this block of fusible links…which helpfully has “HEAD(L)” and “HEAD(R)” on it. So I wiggle some wires, and when I wiggle the orange one (which is NOT for the headlights), the headlights come on!


Um…alrighty then. Then I replaced some blown fuses and everything went haywire….put on the hazard lights: headlights will come on (but hazards won’t). Put on the park lights: headlights will come on (but park lights won’t). Press the brake pedal: headlights will come on (but brake lights won’t). Turn the headlight switch: nothing….go back under the bonnet and wiggle the fusible link block again: somewhat returns to normal but indicators don’t work. And hi-beams don’t work.

So I take off the dashcluster to have a look behind and the surprise was that the wiring is very hacked-up…there are vampire taps (with cut off wires) everywhere, and lots of wiring has been re-routed to different things…the most bizarre thing is that there is a wire tapped into the instrument lighting that goes to the front of the car….I suspect that some genius decided to use it to trigger the headlight relay (maybe the headlight stalk is broken)…and if the headlight switch is somehow bypassed then it might explain why hi-beam doesn’t work.

Oh dear…well, this is pretty much the limit for me. I’m okay at taking apart the oily bits but I can’t even figure out how to use a multimeter. So I think the next step will be to get an electrician over to spend maybe a whole day on the car cleaning up things. Will be expensive but if it fixes the electrics for good and is reliable, then it’ll be worth it. Some amateur MacGuyver has been at work butchering the electrics, so getting it sorted properly will be a priority…if only to avoid the embarassing scene at the engineer when they ask me to test the brake lights and the headlights come on instead.

A few weeks ago I said that when buying old cars, it’s better to buy a car that’s in regular use, rather than a car that’s been lying idle, like mine has. Maybe I should start taking my own advice! But I think we’re close…very close to getting the car nice and solid for the road….anyone know a gifted auto electrician in Sydney?

This post is filed under: project hakosuka.

9 Responses to Project Hakosuka: .Oops. Hit a snag.

  1. leongsoon said:

    Pretty high idling, and slow on the return, but that’s a sweet vroom coming out of the engine! Oil pan is interesting, didn’t know you can extend those!

    Btw, Hakosuka’s sweet and all, but I’m missing my daily dose of JDM goodness from this blog!!

  2. Kev said:

    Yes, very sorry about the temporary interruption to the normal flow of JDM new and views 🙂

    At the moment my mind’s just full of “ok so if I do this, then I have to fix that…and if I do that, then I have to adjust this…” 😀

  3. MrHijet said:

    Too bad that I live in Germany. I am no electrician god, but I assume I could solve that mess.

    Good luck.


  4. zcar4me said:

    Just stumbled upon this site. I’m digging the progress on the hakosuka! Same goes for the rest of this site!

    I’m decent with a multimeter, but Texas to Sydney is a drive. 😉
    Hope for good news on the next update…


  5. leongsoon said:

    Kev says:

    ‘At the moment my mind’s just full of “ok so if I do this, then I have to fix that…and if I do that, then I have to adjust this…” ‘

    Very understandable 🙂

  6. SubaruG said:

    When I first got my RA21 it was the same thing. Orig owner couldnt figure out why he couldnt start the car with the ket so he spliced in a starter switch. Couldnt figure out why the wiper switch didnt work…added in a new wiper switch, and so on and so forth. This took DAYS to sort out and the biggest asset was a factory wiring diagram. The colours on all the wires was diff due to being replaced but at least it shows you the path to start over and fresh.

    As for the carbs, get them to a rough tune so the vehicle can be slowly driven, and do youself a huge favour and get it to a dyno. That was the best thing I ever did to my car and that was to have the carbs dyno tuned and properly synced. I went to a local Volks Wagon specialist and he did a great job. Good luck and I look forward to future posts!

  7. Kev said:

    Cheers for the encouraging words guys.

    The more I think about it, it sounds like the headlights and the fusebox are competing for the same limited flow of electricity. Like I said, at one point when the headlights were on, the clock stopped. And didn’t start ticking again until the headlights were off. Same with the park lights, hazard flashers, etc…ie things that go thru the fusebox. And another time, I could only get the headlights to come on if I disconnected the fusible link to the fusebox.

    So…it sounds like say, the headlight relay trigger wire got shorted against the chassis. So headlights are getting current (direct from the battery) but the relay doesn’t get triggered. Then someone rigs up another power wire to the relay (from the instrument lights) and that makes the headlights come on…but the original wiring is still shorting somehere….and since the trigger wire is powered by the fusebox, it doesn’t leave enough juice to run the cabin electrics….which is why the clock stops when the headlamps are on. And why sometimes disconnecting the fusebox power feed makes the headlights come on….and why sometimes turning on something in the cabin turns the headlights on.

    So the cause of it all isn’t going to be the fusible links block (although it is dodgy if wiggling it makes any difference), it is in the wiring downstream of it somewhere. So what I should do, is remove all of the bandaid wiring, check for shorting wires, and then go from there. Sound about right?

  8. 31GUN said:

    The way I understand it, electricity waits inside things and then jumps out and belts you one.
    It sounds like your car was wired up by Lucas, which is strange because your car is Japanese.
    Want me to come over and help?
    I’ve got some scotch locks, a pair of pliers, and a hammer.

  9. Kev said:

    There are already too many scotchlocs on the car. The hammer, however may come in handy if it doesn’t fix itself very soon.

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