Hi guys i recently did a rats nest delete and i installed the RB powerpulse intake, k&n filter and i now have the full RB exhuast (finally! **** this thing is pricey! > )

Any i took her for a spin today after all this and i have seen ZERO improvement on my "benchmark run" my benchmark run is from a stop to a speed limit sign, on stock i could hit this anywhere from about 62- to sometimes 64 (no idea why, but sometimes i would feel a definite "bump" in performance on my car, never narrowed it down) and today i got.... 62mph. now i KNOW i need to tune this bad boy after i installed all of this by my damn o2 sensor went out and im getting a new one in hopefully by the end of the week. But what could it be? ive recently began running 2 stroke after my omp went i out (i suspect its out, my oil level ISNT dropping at all now, will diagnose when i ahve time)

So once i get my new o2 sensor in. how do i go about changing AFRs at WOT? do i even need to after all this? also i removed my rats nest and i know that does things to my vauum advance and retard. would that be affect anything? right now i just did it as the rats nest delete guide said and they are borth hooked up to vauum via a t adapter to the first port on the carb.

its pretty damn irritating after all this time and money that ive literally got NOTHING to show for it besides a slightly better sound and shittier ground clearance.

 

The rats nest is not gonna give any improvement, neither is the k&n, but the exhaust should give some. Did you replace the muffler too?

I'm sure some FI folks will chime in.

 

1st,how do you know your O2 sensor went out? O2 sensor will not affect wot performance. Its job is to help fine tune mixtures for fuel economy.
There is no doubt you have some deficiency in your car judging by skimming your other threads about rats nest removal. You understand removal of the rats nest does not give a performance boost right? It does often cause driveability issues.

Every RB system i ever installed gave a measurable performance boost...over a stock car that was running well with all specs correctly adjusted prior to the exhaust swap. You can't fix performance problems on a car not running right by bolting go fast parts on it,rotary or otherwise.
Did you replace all the hangers in your exhaust system when installing the RB parts? There are not many reasons for RB system to have"Shitty" ground clearance issues,it's not normal. Not replacing worn out stretched 35 year old hangers is one and tightening installed components in wrong order is another.

 

I forgot to mention my car is carbed and my wideband gauge is throwing the error for bad o2 sensor.

 

We need details or put them in your signature. Is it a 13B or 12A? What carb? What intake? We can't help much with vague statements given so far.

The correct way to mount the RB system is to use a jack to press it up close to the bottom of the car loosely bolted together (headers included). Use new hangers. Tighten from front to back to make sure its put up out of the way and no ground clearance issues.

 

12a Nikki carb.

 

The O2 sensor in question is for wideband readout and does/will not affect performance of the car in and of itself.

Again,if car didn't run properly prior to installing RB system,it can be hard to judge actual benefits derived from installing the system...however there is always a power bump felt on a RB System install,especially on the top end of an otherwise good running car.
If no power gains are being realized after exhaust install,revisit carb operation,be certain engine is timed correctly mechanically,base ignition timing and verify centrifugal and vacuum advance are working correctly.
Has engine ever been compression tested?

 

Some people have already responded on rat nest, it does not improve performance; just makes engine bay cleaner (IMO), and easier to swap out carbs. But you will have to be ok with drawbacks from its removal (A/C, cruise control operational smoothness). Currently I run a RB dual primary exhaust and RB filter system. Changing to RB from stock exhaust with stock Nikki had to make it slightly richer due to leaning out on top end; noticed improved mid/high end. Now run "fat" Nikki, had to adjust idle slightly (idle at 850 RPM) in both set-ups ran pretty stock timing settings; much better mid/high end (really strong top end). Love the Nikki (especially "fat"), never had any flooding or issues in heavy cornering. Not a carb rebuilder (many experts in this forum); but a well tuned Nikki in either form runs well. Wish I was better it tuning the AP spring, I sometimes (very, very, rarely) get that hiccup when hitting full throttle at low RPM (right around the secondary opening).

 

Om so i know the rats nest removal dlesnt give power. I was just gking through the list lf recent changes.

compression numbers were 85 across all faces and rotors last time i did it. Maybe around 87.

whats a good guide on figuringout timings?

 

Something i forgot to mention earlier, when i pull my choke out, it doesnt change engine RPM almost at all. could that be related to whatever issue im having?

 

GSLSEforme Good to see you back posting your valuable advice.

 

There are two timing marks on the main pulley and a pointer (see pic). The mark on right (looking from front) is the leading mark, and the one on left is trailing mark. With car running hook timing light to L1 spark plug wire (front rotor, bottom plug). Point light at timing pointer (see pic again). The pointer should line up with leading timing mark (on right in picture). If not, loosen the nut (bolt?) that secures the dizzy, and rotate until the pointer lines up on the mark. Resecure the bolt. I think it's a 10mm - I use a socket wrench and long extension. Done.

 

You really don't give us much info to go on. Are you talking about when the engine is cold or warm? If a cold start and the choke doesn't raise idle, then it's not hooked up right. Choke operation is a totally different "circuit" than normal carb operation on a warm engine. In other words, choke has nothing to do with normal "warm engine" operation.. You're driveability issues are not from your out-of-wack choke (unless the choke is always stuck closed).

 

 

With the carb stripped and the rats nest gone, there is nothing left to set the choke. It is not mechanically connected to the "Choke" cable, but depends on the vacuum from the rats nest and portions of the components that have been stripped from the carb to operate. If you want it to operate via the choke cable, it must be physically connected at the air horn so that pulling the choke cable sets the choke butterfly.

 

On a cold engine, good to know the choke is useless, oh well.

Anyway i think ive narrowed it down to my secondaries not opening all the way, they are only opening about "40%" and it doesnt seem like the engine is being sufficatted. this has been a pain in the butt to confirm but i was looking at my throttle cable last night to see if it was out of wack and cuasing this (it was a problem before) and i manually moved my primaries to confirm that the are opening fully without "snagging" or anything and i did the same to the arm for the secondaries and it would go to about 40% and suddenly become MUCH harder to move, so i sprayed the crap out of it with carb cleaning inside and out and took her for a spin and it was much better for my benchmark run i got about 65.5. mph so a definnite improvement! and i can feel it in the ole but dyno for sure. and now its back down to about 60 :/

Anyway would could be cuasing my secondaries to only open to about 40% and suddenly getting alot harder to turn by hand? was its vacuum somehow powered by the rats nest? as far as i know its not. ill be looking at my timings tomorrow, it doesnt look like someone fucked with it at some point.

 

I was never quite sure about this. When I rebuilt my Nikki I stripped it, did the AP mod and mechanical secondaries. Full Rats Nest and Emissions deletes. The choke ****/electro magnet 100% still controlled cold-start hi rpm, but I had removed the butterfly so can't speak to the actual "choke" function.


The nikki seems to be a combination of every different type of choke ever used. You have a mechanical choke system. You have an electric coil choke system. You have some sort of vacuum pot controlled system. Every other carb I've had used only ONE of these (or a hot air coil). But the nikki uses 3 out of 4 styles of choke. All at the same time.

Don't get me wrong.... when in good shape the motor runs almost as smooth as FI in any climate. I think it was as close as Mazda could get to a FI engine, before actually going FI.
But boy is it a complicated mess.

 

Agreed, and no need for the choke flap if the idle air bleeds are changed. Don't forget about the bi-metal spring with the wire (that would kind of qualify as electric choke, but there is also a magnetic choke **** holder which also uses a coil, so I wasn't sure what you meant).

All I keep from that complicated mess is the fast idle linkage, but I almost never use it.

 

they kind of did overdo it, but the considerations were that the engine needs a LOT more fuel to run well when its cold, but then if the choke is left on too long, too much fuel would ruin the converters. and then the carb also has to be able to deliver full power when its stone cold, or nearly so.

so they have a complex choke system, it does work though

 

for now just set it to the stock marks.

 

Just to make sure we're covering the basics, when you, OP, are testing the secondaries and feeling this 'hard to move after 40%' gig, you have the primaries fully open, right? If not, well there's your problem. The secondaries are designed to stay closed until the primaries open ~50%. If you move the secondaries by hand without the primaries being open, they will move so far with a little effort, but then suddenly get more difficult to move as the linkage hits the left side of the "Y" (I'll try to get a picture of this because I ref. it later on as well) which is essentially a safety stop of some description. If the primaries are open a little bit, the secondaries can move farther before hitting this, but they will still eventually hit it unless the primaries are open wide enough. Usually there is a small gap between the left side of the "Y" and the primary linkage (of which there are many and hence why I will get a photo) and that's why a small amount of secondary movement is possible by hand.

Now then, the below are possible cases if you are indeed opening the primaries to test the secondaries and still having issues. I also wrote this before the above so... yep.

While the secondaries could just be gunked up somehow, I'm wondering about the linkages themselves (although they should be fine unless someone messed with them). The secondaries are connected to this "Y" shaped linkage on the primary shaft that limits when the can open until the primaries have moved a certain distance. If that linkage were somehow messed up, that might cause this secondary opening issue. I would do whatever test you were doing to find how far the secondaries open, but look for this "Y" while doing so. If the primaries are fully open and the secondaries can not be, and if the primary linkage part of the assembly is touching the left side of the "Y" during this, there's an issue.

What is more likely is that the vacuum diaphragm is a little tired. Try disconnecting it's linkage with the cotter pin and see if that changes anything (don't drive like this though).


Okay, here's the photos. They are of my modded carb's linkages, so not everything is present and you will notice the "Y" is stainless as I did some retiming for mech secondaries, although the concept is the same.


Blue is attached to primary shaft, red (the "Y") floats on primary shaft and is connected to the secondaries.


The blue arrow is pointing to the gap that allows this freeplay in the secondaries.

 

WTH my last post didn't post! augh.

Anyway i foun out right before i read the post above that primary and secondaries being related to each other that i need to open the primaries first. when i hold the primaries open the secondaries move freely to WOT but my primaries seem to stop around 85% open and not want to go anymore no matter how hard i try to open them. is there some kind of adjustment for how far they can open?

 

Need a bigger hammer.

 

found it! what the hell is this limiter looking thing here? its threaded pretty close to the top (i took it off briefly to see if it freed it up to move more, and it did.) right now. can i just take it off and leave it off?

 

If you take that off your secondaries won't open when they're supposed to. I drove my car all the way from Providence RI to Philly when I bought it and didn't know why it didn't have any power on the highway. Looked at it more closely the next morning and found that little thingy hanging loose. Put it back on and Vroom Vroom, burnout time!

Here's the best pic I have on file. Where I have mine adjusted is where it allowed my nikki to work the smoothest and open best. If you pull that threaded rod/block thing off of the see-saw part you can turn it to adjust it tighter or looser. It's just like a nut on a bolt. It controls the interaction between the primaries and secondaries. In addition to other parts of the linkage down by the throttle shafts. Yeah, like I said earlier in this thread, As nice as the nikki works it sure does it in the most complicated ways.

Warning - when you take that "nut" off the see-saw rocking part it will be hard to get back on. Spring pressure will fight you getting it back on there. To get mine off and on easier I used a piece of thin wire to "loop it" and pull it up while pushing the rocker down... to get it back on.

All that being said... I don't really think this is your problem.