Datsun Roadster Forum-311s.org

I wanted to put this out there for anyone searching. Here is an option to get Mikuni carbs on your Roadster. I'm sure there are cheaper ways to do this, but here is my current plan which has just been sprung into action.

1. Purchased Cannon intake manifold w/linkage from JAM Engineering - part 99003.830
2. Having the manifold shipped directly to Wolf Creek Racing in New York
3. Purchased the pair of Mikuni 40s from WCR. Todd is going to restore/refurb a set and jet them for a stock 1600. According to him it will "get me close" and sounds like it will come with some other jets in case I need to do some adjustments.
4. The linkage - since the manifold is made for Webers, there are some modifications to be done. But Todd has been through this before. He has the parts to make the linkage work just fine on a roadster, so for "no more than $200", he will mount them and do the linkage, which requires the O-ring insulators, link rod assembly, and some other little parts. But I like that he was familiar with the manifold.
5. Also purchasing the air horns and new K&N style filters and chrome housing from WCR.

It will probably be around 3-4 weeks before I have them so I'll update the thread. But I wanted to capture this for future reference. Guess I'm slowly working my way to strokered.

When you get them, I would like to see a photo of the linkage setup that Todd puts on it.

That will be fun. When you talk to JAM - tell them to make a U-20 manifold for 44 or 45mm Mikuni or Weber carbs

Cheers
James

dridge11 wrote: 3. Purchased the pair of Mikuni 40s from WCR. Todd is going to restore/refurb a set and jet them for a stock 1600. According to him it will "get me close" and sounds like it will come with some other jets in case I need to do some adjustments.

Or consider an inexpensive wideband O2 sensor system and take the guessing out of it! Since you'll have the intake off, easy to pull the header and get a bung welded in (if it is not stock; not sure on stock exhaust manifold). Money well spent!

jamesw wrote:That will be fun. When you talk to JAM - tell them to make a U-20 manifold for 44 or 45mm Mikuni or Weber carbs

Cheers
James

JAM is a reseller. They are getting the manifolds from Pierce. As few 1600 units as they sell, I doubt that they would tool up to make a solex manifold for the 2000.

Gregs672000 wrote:

dridge11 wrote: 3. Purchased the pair of Mikuni 40s from WCR. Todd is going to restore/refurb a set and jet them for a stock 1600. According to him it will "get me close" and sounds like it will come with some other jets in case I need to do some adjustments.

Or consider an inexpensive wideband O2 sensor system and take the guessing out of it! Since you'll have the intake off, easy to pull the header and get a bung welded in (if it is not stock; not sure on stock exhaust manifold). Money well spent!

Couldn't you weld the bung into the head pipe or flexpipe? With no cats, it shouldn't care where it's mounted.

The Innovate manual says you can even clamp it to the tailpipe if you don't have a Cat.

Cheers
James

I'm also curious to see the linkage. I'm at that point myself. You might ask him about port matching the intake, as it is quite a bit off. Not a great casting.

shifty wrote:I'm also curious to see the linkage. I'm at that point myself. You might ask him about port matching the intake, as it is quite a bit off. Not a great casting.

+1 on the casting quality. I had one of those manifolds, and while it would work fine, it left a lot to be desired from the perspective of being concentric.

With computer design/production, water jets etc, it wouldn't be very difficult to fabricate a good intake, 3 flanges, 4 tubes and a TIG welder. Might not cost anymore than buying one.

Parts 1 and 2 are complete - intake manifold is in route.

Yesterday, I met Mike Young on his way through town and received a nicely polished GM alternator, early brackets/hardware, and a new belt. Add that to the pile.

Intake manifold is scheduled to arrive at Wolf Creek Racing today! Though it sounds like he's a little backed up with orders, so it may still be a week before he starts in on my carb/linkage setup.

Gregs672000 wrote:

dridge11 wrote: 3. Purchased the pair of Mikuni 40s from WCR. Todd is going to restore/refurb a set and jet them for a stock 1600. According to him it will "get me close" and sounds like it will come with some other jets in case I need to do some adjustments.

Or consider an inexpensive wideband O2 sensor system and take the guessing out of it! Since you'll have the intake off, easy to pull the header and get a bung welded in (if it is not stock; not sure on stock exhaust manifold). Money well spent!

+1 on the wideband. Even a narrow-band (dirt cheap) can help.
The real-time feedback on air-fuel ratio is the way I "became one" with my Mikuni's.

Pilot jets, air jets and main (fuel) jets are pretty straight forward. Where you need less air INSTEAD of more fuel can be a little more complicated.
Tuning your accelerator pumps (hardly ever necessary) involves not only the point at which the mechanical arm actuates the plunger, but also the pump jet size (how quickly the extra dollop of fuel comes out).

Putting the throttle wide open and watching the AFR from 2k to 6k rpm can give you great info - it will vary!
Stomping the throttle at 2k versus stomping it at 4k will give you good info..
This becomes REALLY EASY if you have real-time feedback. And the pleasure of driving well-dialed Mikuni's is your reward.

Sounds like something to consider for sure...but where do you put that gauge? I'm not really keen on having a modern gauge mounted in plain sight.

You don't have to mount a gauge in your car. You can just use one for tuning/jetting the carbs and then disconnect it after that.

Cheers
James