Dual Mikuni Center Pull Setup

[Stoffregen Motorsports]

ddgonzal's is not centerpull either

 

this is centerpull: (nissan comp?)

 

 

I just noticed one problem with this picture. See the brackets on the outsides of the carbs, he's probably using those for return springs, and the one on the left looks like he's got an idle speed adjustment screw. These are both bad ideas, the added springs on the outsides of the center pull linkage twists the throttle shafts and can bend them. You only want the springs and the idle speed adjustment screw on the center pull itself.

[Silky_Johnson]

Silky is correct. This is the center-pull linkage style I was referring to. The upper linkage piece in this Troy Ermish photo shows exactly the center-pull in discussion.

 

 

On the Ermish set, I think the photo on their website is for Webers. It looks like he was using the same photo for both the Weber kit and the Mikuni kit. So I think the photo above was actually a DCOE kit, not PHH.

[Burabuda]

I just noticed one problem with this picture. See the brackets on the outsides of the carbs, he's probably using those for return springs, and the one on the left looks like he's got an idle speed adjustment screw. These are both bad ideas, the added springs on the outsides of the center pull linkage twists the throttle shafts and can bend them. You only want the springs and the idle speed adjustment screw on the center pull itself.

noticed that too, so is that something modded, or is that the way the nissan comp setup came?

[oldskoolvws]

On the Ermish set, I think the photo on their website is for Webers. It looks like he was using the same photo for both the Weber kit and the Mikuni kit. So I think the photo above was actually a DCOE kit, not PHH.

 

Correct, was just using as reference for the system.

 

I just noticed one problem with this picture. See the brackets on the outsides of the carbs, he's probably using those for return springs, and the one on the left looks like he's got an idle speed adjustment screw. These are both bad ideas, the added springs on the outsides of the center pull linkage twists the throttle shafts and can bend them. You only want the springs and the idle speed adjustment screw on the center pull itself.

 

I bought a set of carbs with to outer springs and center pull setup. I also have a NOS center pull kit, it has the outer brackets for springs...I think. I take a picture.

[oldskoolvws]

Here's a complete NOS Mikuni Center Pull setup. It is a Toyota setup, but is pretty universal as I think they just stapled bags of parts that were needed for vehicle specific applications. On the top left and also the two lower pieces in the center is what makes up the center pull sections (two lowers because the cross connect tabs are different lengths to accomidate different manifold spacing). The two lower outer arms (left and right) are the spring arms. On those arms you can see the screw holes and the screw (center of the picture) for the adjustment. There is no way those spring arms will fit in the center along with the center pull setup. They have to go on the outside which would contradict the previous statement that they should not go there or have an adjustment.

 

In case your wondering, the little bag on the lower right just held the extra the extra arm that sits in the lower middle. The kit is complete.

 

 

[Burabuda]

^ u sellin or just fyi?

[Stoffregen Motorsports]

Here's a complete NOS Mikuni Center Pull setup. It is a Toyota setup, but is pretty universal as I think they just stapled bags of parts that were needed for vehicle specific applications. On the top left and also the two lower pieces in the center is what makes up the center pull sections (two lowers because the cross connect tabs are different lengths to accomidate different manifold spacing). The two lower outer arms (left and right) are the spring arms. On those arms you can see the screw holes and the screw (center of the picture) for the adjustment. There is no way those spring arms will fit in the center along with the center pull setup. They have to go on the outside which would contradict the previous statement that they should not go there or have an adjustment.

 

In case your wondering, the little bag on the lower right just held the extra the extra arm that sits in the lower middle. The kit is complete.

 

 

 

They actually do fit on the inside, between the carbs. Try it and you'll see. If you mount them on the outside, you won't have an idle adjustment and you will bend your throttle shafts.

 

There are three arms pictured in the kit, but you only use the two on the inside.

 

I've set dozens of these up before and that Toyota kit is the universal center pull kit of choice. I can't believe nobody makes one like it! Really?

[Stoffregen Motorsports]

Oh yeah, and weld a reinforcement tab on to the cable bracket or it will bend and break over time. It's a piece of junk.

[oldskoolvws]

^ u sellin or just fyi?

Either or....I will sell but I gotta tell you it''s not cheap. I paid $200+ for this setup.

 

Oh yeah, and weld a reinforcement tab on to the cable bracket or it will bend and break over time. It's a piece of junk.

 

I was thinking of trying to adapt the Suzuki Samarai throttle cable to the center pull setup. But I think I have to find a new manifold.

 

[oldskoolvws]

I finally took the time and dug out this set of carbs and the manifold. Here's the ACTUAL problem with with Mikuni Carbs, Center Pull Setup and Mikuni Manifold:

 

Here you can see, even with the isolator, the pull arm is too long and hits the Mikuni cross bar. The carb lifts up. This is the natural closed position of the arm.

 

 

I biased it off the side of the stud to sit flush with the manifold and you can see how far down the pull arm sits.

 

 

I even thought of double stacking the isolators, but here you can see it still hits.

 

Okay now what? I thought of cutting the linkage arm and shortening but not sure how that will impact the the throttle response and overall drivability. There has to be a solution...I really want to run a Mikuni manifold with Mikuni Carbs and center pull...

[68Datsun510]

This is where those thicker isolators Nissan made come into play.

[oldskoolvws]

This is where those thicker isolators Nissan made come into play.

 

I've been looking into flange adapters, essentially the flanges for making your own manifold. Obviously instead of making a manifold though, I'd use it as a spacer.

 

[Stoffregen Motorsports]

This is where those thicker isolators Nissan made come into play.

 

That's what I've been trying to explain. I'll get some pics later today.

[oldskoolvws]

That's what I've been trying to explain. I'll get some pics later today.

 

I hear you guys and I know what your saying. Part number 16174-25501? I like these too.

 

[68Datsun510]

Strange...whats the point? Zero isolation...

[oldskoolvws]

Spacer only. Still need to add isolation.

[Stoffregen Motorsports]

This is the correct way to set up a 2TG centerpull linkage. Notice the springs are on both levers, but these levers are the only two mounted on the carbs. There are not to be any linkage levers or springs on the outsides of the throttle shafts. Also notice there is only one idle adjustment. Set up this way that's all you need. There is a balance adjustment on the center lever, but that's not to be confused with an idle adjustment. Lastly, notice the clearance made to the manifold on a mill. It is minimal because I set these up with the NISMO soft mounts which are thicker than other soft mounts (or isolators).

 

 

 

 

 

[Stoffregen Motorsports]

One other thing to notice is the 12 point metric jetnuts on the backside of the manifold. If these are used (6 point or 12 point) then there is much more room to get a wrench on.

 

[oldskoolvws]

Thats a nice clearance job on the mill. I'm hoping to get away from that though but am beginning to think it's not possible. Maybe I'll just jump and mill it at work.

 

Are the NISMO mounts still available? Part number?

 

Also, anyone know the thread pitch for where the banjo bolt would normally go for the fuel line? I want to do like this setup and go to compression fittings for fuel lines.

[Stoffregen Motorsports]

Thats a nice clearance job on the mill. I'm hoping to get away from that though but am beginning to think it's not possible. Maybe I'll just jump and mill it at work.

 

Are the NISMO mounts still available? Part number?

 

Also, anyone know the thread pitch for where the banjo bolt would normally go for the fuel line? I want to do like this setup and go to compression fittings for fuel lines.

 

Thanks. The NISMO isolators may or may not still be available, but there is a similar part for a 2000 Roadster that should be available still. It is 16174-25501. The main difference is the bolt spread on the manifold side, which is slightly wider than the carb side, and incidentally, works better with the Mikuni manifold.

 

Check out this thread: http://community.ratsun.net/topic/48146-sidedrafts-without-softmounts/

[Stoffregen Motorsports]

Also, anyone know the thread pitch for where the banjo bolt would normally go for the fuel line? I want to do like this setup and go to compression fittings for fuel lines.

 

I think it's 12 x 1.25, Weber is 12 x 1.5. Pegasus sells a bunch of stuff here: https://www.pegasusautoracing.com/group.asp?GroupID=FUELPLUMB

[oldskoolvws]

Thanks. The NISMO isolators may or may not still be available, but there is a similar part for a 2000 Roadster that should be available still. It is 16174-25501. The main difference is the bolt spread on the manifold side, which is slightly wider than the carb side, and incidentally, works better with the Mikuni manifold.

 

Check out this thread: http://community.rat...out-softmounts/

 

From your other post:

Lastly, the part number for the stock Roadster offset isolators is 16174-25501. They cost about $35 each. As far as I know, Nismo no longer makes the non-offset isolators. If you want to use the roadster isolators you will have to slot the holes in the manifold.

 

When you say slot holes in manifold, your talking about the stud holes correct? Not the channel you milled for the linkage.

 

I think it's 12 x 1.25, Weber is 12 x 1.5. Pegasus sells a bunch of stuff here: https://www.pegasusa...oupID=FUELPLUMB

 

Confirmed. Mikuni is 12x1.25.

[Stoffregen Motorsports]

Yes. The stud holes. On a Mikuni manifold, there are normally studs that bolt the carbs to the manifold. When you use Nissan isolators (soft mounts) you need to remove the studs drill out the holes to accept the studs built into the soft mount. But, on the Roadster soft mounts, you need to slot those stud holes outward to accept the wider bolt spread built into the soft mount.

 

The major benefit to using these Roadster soft mounts is that the mating surface of the nut will sit flatter and it is easier to get a wrench on the nut. If you used the NISMO soft mounts, then you would have to spot face the backside mating surface and even grind for clearance inthe tighter spots on the underside of the manifold.

[69srl311]

Someone say roadster linkage?

 

http://www.fairladyparts.com/page28.html

[Stoffregen Motorsports]

Someone say roadster linkage?

 

http://www.fairladyp...com/page28.html

 

Actually I was talking about the Roadster carb isolators, but I just looked at your link and that looks like a pretty nice kit. It may be a bit wide in the middle for a L series Mikuni manifold, but that can easily be modified.