Just installed bigger carby...

[dank]

I've had a nikki two barrel carby sitting around at home for about 18months now that came with a head, manifold and reground cam i bought as a package. apparently carby is off a datsun stanza or mitsubishi van of some kind, old skool but works well!

When bigcam and I rebuilt the bottom end we put the other head on as it looked newer and the reground cam. just with the reground cam we noticed the engine to rev more freely through the rev range and seemed/felt to move the torque "band" into a higher rev range at around 3500-4500rpm with the standard carby.

With the standard carby, it pretty much packed itself in last friday night on a night drive where we couldn't get it to idle and after trying everything we were able to get it to rev erratically around the 2000rpm point which was sh!t for off road but kept me going, the ford alternator also stopped charging after a huge spark flew out while were were mucking around with the idle and I just made it home.

I decided on the weekend to bite the bullet and put this new carby on which has a power operated choke (no hot water in/out like sierra carb) vacuum secondary and much bigger primary and secondary chambers. THe manifold as I bought it had been modified(ground out) to suit the bigger chambers and butterflies allowing them to open and close freely. after sourcing a new main gasket from SE carbys @ 29 Foster st Dandenong, good blokes there i put it all together, re routed some of the hot water lines and closed off some unneeded vac lines. Sorted out the wiring for fuel cut-off solenoid and idle mixture solenoid(?) and the thing ran!!! I was pretty happy at this point and it was idleing much better than with standard carby although the lumpy cam gives it a rough note.

took it out for a spin and noticed that in 4th gear it made much more power right up through to 5500rpm @ ~115km/h and sat there quite comfortably...changing into 5th gear it dropped back down to about 97km/h(gps) at ~3850rpm and when i booted it it wouldn't go any harder than this....

I'm thinking that it may be running lean at this point, what do people think?

Anyway thought I would share my experience with this as overall the zook is now going really hard but I think I need to get more fuel to it

...what might be my options.??


...i'll post some pics tomorrow... , now its just the alternator to fix...

[Kitika]

Did you check the spark plugs to see what colour the fuel/air mixture is burning on them? That's the easiest way to check if its lean/rich.
Would like to see some pics of the set up

[dank]

Spent some more time on it today. found idle mixture and fuel pressure screws and have fixed the idle. mucked around with the fuel pressure screw it was set on a lean level so i cranked it right out until is started bogging down around 1500 - 2000rpm then backed it off a touch.

took it for a drive and I cannot believe how much faster the thing is. at around 4800rpm the secondary kicks in and it literally kicks hard and keeps pulling up to 7000rpm...thats as far as I wanted to take it...i think the combo of the reground cam, carby, rebuild, exhaust, intake and extractors have made for a gutsy little engine...I think i'd kill myself if I had anymore power.

Yes dirty motor I know...part of wheeling in SE vic

Wiring is still a bit of a mess...and not sure if all vac lines are heading in the right direction but its working 10 times better than the standard carb so no stress




The auto choke was missing a spring so I gotta track one down. I have put in a temporary spring until I get a replacement.

[/img]

[Kitika]

So does this carby bolt straight onto the 1.3 manifold or does it need be modified? I like the look of that leaning and richening mechanism looks much easier than playing round with jets and float levels!

[dank]

So does this carby bolt straight onto the 1.3 manifold or does it need be modified? I like the look of that leaning and richening mechanism looks much easier than playing round with jets and float levels!

The bolt pattern for this carby is the same but due to the larger diameter primary and secondary chambers and butterflies the previous owner of this setup had ground out one large hole in the top of the zook intake manifold allowing proper operation and flow from both cylinders in the carb.

That mechanism is the auto choke, you can control how fast or slow the butterfly opens depending on whether you are in a hot or cold environment. doesn't have an effect on fuel flow. THere's a coil in there that heats up and I guess by heating up the coil it heats up the spring therefore reducing the tension and allowing the choke butterfly to open. I have a different spring in there that doesn't heat up enough at the moment...won't worry too much unless it gets hard to start in winter...

it seems to be jetted very well for the engine and I can't imagine it getting any more power by mucking around with other jets...I'm not going to bother. Float levels can be modified as can accelerator pump, idle speed, idle mixture, and fuel pressure...alot more user friendly than the aisin carb.

[nicbeer]

sounds like what i had to do to fit the toy carb onto mine,