Nikki Modification finally

Engine related articles specific to induction (carby, EFI etc.)
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troyrotor
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Post by troyrotor »

yeh some bits probably are. i just tried my best to get the best flow, really just an experiment anyway. what do you reckon isn't necessary?

according to the chart a stock nikki should flow more than a 32/36. well in theory anyway
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dbart1961
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Post by dbart1961 »

You mention the carby for the G161 and the G180 are slightly different so does that mean if you have a G180 i should start with a carby from a G180 as the jets are bigger?
I am currently running a 32/36 Weber and just can't get it right so I want to go back to the Nikki but I don't know which carby I should start with.
It is a G180 bored 60thou, TX head and extractors. Mild cam.
Are any of the G series engines carbies compatible. Like out of early Rodeos and Jackaroos?
Regards, Dave
troyrotor
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Post by troyrotor »

some of the jets you will need will be from the 1.8 carbi and because your cam and bore size some 2l jets may be useable. If you have both i would start with the 2l and use some jets from the 1.8.

On the other page shows a pic of the different stock jets between 1.6 and 2l some change and some stay the same, use that as a reference, i think you should set it up using all the 2l jets see if it runs rich at different points and the change to the 1.8 jets where you need to, as in idle, highrange, lowrange etc.
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dbart1961
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Post by dbart1961 »

Thanks but where can I get the jets? Should I just get a Carbie from a 2L Rodeo or something?
Regards, Dave
geminilover3236
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Post by geminilover3236 »

mechanical secondary does make a difference.
I zip tied the secondary on and I noticed a power increase however, you can't really put your foot down until you've got the revs up a bit.
geminilover3236
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Post by geminilover3236 »

Did you ever figure out that accelerator pump?
troyrotor
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Post by troyrotor »

yer i lathed up a new shaft so it had more travel as the standard pump bottoms out. i also made up new arms and mounted the linkage closer to the pump to acheive more travel and tuned the adjustment nut to have more lift and allow the pump to get a full throw without hitting the bottom.
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geminilover3236
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Post by geminilover3236 »

And was it terribly successful?
troyrotor
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Post by troyrotor »

yer definitly worked well, tuning the accelerator pump was annoying but when i got it right was very smooth and good acceleration. could boot it from 3/4 throttle without any hesitation
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geminilover3236
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Post by geminilover3236 »

Yer, that's it, trying to get rid of that hesitation or bogging down.
I'm a little confused as to what you've done to it though. Do you have any pictures...? That'd be awesome.

What about the G200 pump, they're no help? One of my 1600 carbys had one in it. strange...

Basically I'm doing this mod same as yours and then recurving the dissy (one of your other mods) and hopefully that'll see her running nicely.
troyrotor
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Post by troyrotor »

well i also had a 1600 carb with a larger pump in it too that i beleive is the same as the g200 one. so maybe just later models had it or something.

if you have a good look at the pump diaphram and rod spring assembly you will find what things are preventing more travel.

if i remember correctly there is a circlip kinda thing above the spring, i found that the diaphram met with the spring before hitting the bottom of the chamber. so i made a new grove slightly higher up for the circlip insted. the diaphram could then travel further without the spring binding. i also cut a coil or two off the spring and stretched it to fill the area with less coils.

the other thing was that the more travel without the spring binding was now the diaphram bottomed out, so i redesigned the level arm to start more towards the top of the camber finishing just before meeting with the bottom.
but to have that much travel the arm on the throttle shaft had to be extended and the point on the pump arm was shortened. i drilled a few holes to find out the best length in both arms. i should have made new ones with the single hole in the correct place but i got lazy and it ended up breaking cause of all the holes. thats why i dont have the arms anymore. i replaced it with a stock setup and never got around to making new arms. i think i still have the pump though
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geminilover3236
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Post by geminilover3236 »

Thanks heaps mate, I'll go have a good look at it in the coming days and see what I can come up with.
Did you ever have any trouble with the main butterfly shafts being too weak after you shaved them down?
troyrotor
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Post by troyrotor »

na definitly not there is still heaps of meat there. maybe if the carb was boosted at like 30psi i would be woried
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geminilover3236
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Post by geminilover3236 »

haha, schweet as. I will let you/this post know how it all goes when Im done. Thanks for the help.
geminilover3236
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Post by geminilover3236 »

Sorry to post again, but did you modify the bottom spring setup at all on the fuel plunger/pump.
I found that the spring was bottoming out before the thing on this one. I cut 2 coils off the spring and you could feel the extra travel. I haven't yet done the top one. moving the clip further upwards.
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