Is ther a quick and easy way to disable the shutter valve without removing the intake manifold from the engine?

 

pull off the vaccum lines going to it. Then plug one or the other, forget which one. I'm thinking the small one.

 

From my recollection, you plug the big one and leave the smaller one open.

 

Thanks, I'll give it a try. It shouldn't hurt anything to disable it, should it?

 

Cap it off, better to remove it and replace the shafts with carriage bolts and sealant, but capping the lines will get rid of the piece of ****

 

what function does the shutter valve have anyway? Besides clutter that is.

 

A rotary guy that worked for mazda 15 years talked me into putting a new one in mine, says it helps cool the engine. I had it plugged (the big hose, idled much better after) He's doing it while rebuilding the carb for me.

 

Plug the big hose and leave the vacuum hose too it connected. Tried it with the vacuum hose(small) disconnected and plugged and it ran rough.

 

Cool the engine? Say what? Was he smoking crack? The shutter valve purpose is to blow up the 2nd rotor, oops I mean, well heres my explanation..

Upon deceleration the shutter valves closes off all air/fuel mixture to the rear rotor, so it can burn everything in there more cleanly...When throttle comes down to 1200 or so, it open the butterfly back up...

Yank it off there Totally worthless I know a guy that had one bad on his car and I told him to take it off, well instead he left it on there making its 'honking' noise. 6 months later, motor was bad and guess which rotor it was? Coincidence maybe, but anything that shuts the fuel off and continues to fire cant be good

 

crankit & MIKE-P-28 - Thank you... Thank you.... Thank you....

I just fashioned a gizmo outa two picture hangers to clamp that freak'n big hose. I just got back from my test drive and I'm so freak'n happy. What a difference! I no longer have the fsck'n sucking sound and whacked out idle crap going on! It is smooooooth! I also notice that at speed, the throttle-on/throttle-off response is smoother too! Right freak'n on!!!!

I would recommend to anyone who has a 12a to try clampin that fsck'n hose. You_will_be_happy_too! Guaranteed!

Oh, darn... did I forget to say "Thank you"?

 

im nto quite familiar yet with theese engine exactly wich hose is it and where is it located??

 

Looking at the top of the air cleaner from the front, it is located at about the 1-2 o'clock position. It's about 1/2 +/- in diameter and travels down to the shutter valve which is located at the base of the intake manifold above the rear rotor on the engine side. Clamp that sucker! Untill someone convinces me otherwise my clamp stays on!

 

I just used a large red electrical nut that you use to connect wires. Shoved in the hose nice snug fit.

 

does it help get rid of the popping backfiring upon deceleration?

Paul (waiting for acv blockoff plate)

 

Lets see. no cats,airpump still there,blocked shuttervalve hose, no dashpot (looked bent so I tossed it] timing 4btdc(lead) 4adtc(trail) and it still don't backfire?? must be something right

 

Mine didn't backfire before I plugged it and it doesn't backfire now. YMMV

 

the shutter valve is supposed to cut off or (lean out) the back rotors when decelerating. This helps it run cooler and keep it from back firing. I had had mine replaced two years ago.

 

Yep, that's what the mechanic guy told me, too. Hope he's right, that sucker is $100.00+!!

 

Am I wrong in saying that lean=HOTTER?

I know with an oxy/acl torch it dont get hot till you throw the oxygen to it, and then its HOTTER THAN HELL!

So I think you got that wrong with the running cooler part.

 

Rich makes my exaust glow red so I think lean would cool down the rotors

 

I just disabled mine. Now my carburator doesnt hiss when I shift or decellerate. I installed a edelbrock PRO-flow foam Air filter. (big improvement in both power and sound)

The thing would hiss when I shifted. It was a really cool sound. But the smoothness is great.

Stupid stock Nikki and all the bullshit that comes with it.

 

Okay.. here's what I did, somebody tell me where I went wrong:

What I assumed to be the shutter valve control had two vacuum lines on it, the small one on the end routes to the yellow solenoid in the rat's nest (I unplugged it from the rat's nest). The large line off the side of the doohickey routes to the bottom of the airbox (I covered the hole on the inside of the airbox with duct tape).

Watching the valve while reving the engine in the driveway, I could see that it no longer actuated upon deceleration. However, upon test driving the car, I didn't notice any difference in the way that it ran. What's more, after I turned off the car and let it sit for about 1/2 hour, I tried to start it, but it wouldn't fire! I opened the airbox and could see fumes coming out of the carburetor, so I unplugged the covered hole in the airbox and reconnected the small vacuum line. When I started the car (w/ accelerator to the floor.. I think it flooded for some reason), there was a huge exhaust cloud out the tailpipe.

What did I do wrong?

 

ASEmaster,

When I ditched my rat's nest, I had *exactly* the same problem as you just described. Here was the fix for me...

1) I had plugged both inlets on the shutter valve. This is wrong, at least on my 82. You should leave one of them open. Again, I believe this to be the small one. I'm not 100% sure because I don't have a Nikki anymore.

2) I had mistakenly plugged the 'air vent solenoid' on the carb. I thought this was what caused the fumes coming up through my carb. It's a large outlet on the driver side top of the carb, had a large hose going to it from the rat's nest.

 

Can someone please show me a picture or diagram of EXACTLY what I should disconnect, where it should be disconnected from, and what to plug?

 

Would doing this help my extremely unsmooth ride while coasting in gear but not on the gas?