Custom made air box.

[Paul Van Oss]

Thanks guys for all the replies. What would you recommend for jetting?
To secure I am going to install bronze coloured mesh to secure the red foam. Gives it a nice contrast I think.

[bobcat]

Replies ? Well, sort of.
Jetting; As a measuring stick try leaving it stock first. Who knows it might run just fine
but I doubt it. At least you will know if or how much progress you've made.

If/when you make changes, start from the low end and work up. The main jet is the last
thing you want to change. I'm guessing you have the 81-82 carbs, VB64A.
Set the idle mixture screws at 1.5 turns out from GENTLY seated.
Drill slow jets with a #79 drill bit in a pen vice (chuck).
Shim the needles .020" to start. It might take .040".
Lastly change the main jets one size at a time (105 to 108 etc.)
Make sure your accel. pump is working and correctly adjusted.

Opinions may vary.

[daves79x]

My take is that you will be needing to jet very similarly to individual pods, if I'm visualizing what your 'filter' set-up will look like. If that's the case, you'll need to go up to at least 120, likely higher.

Dave

[bobcat]

My take is that you will be needing to jet very similarly to individual pods, if I'm visualizing what your 'filter' set-up will look like. If that's the case, you'll need to go up to at least 120, likely higher.

Dave

May be* but the difference here is that, unlike pods, Paul has the stock velocity stacks which should
restore some of the original fuel demand. I'm searching for the right terminology here; balance,
flow, port velocity, function, ....

Kind of uncharted territory. It will be interesting to see what he comes up with.

*as much as 120.

[bobcat]

One of the overlooked functions of the stock rubber stacks is the staggered lengths
which are intended to compensate for the port length differences. Since Irimajiri
and engineering team had to pull the carbs inboard in the V shape, the stack lengths
were intended to equalize port length, valve to atmosphere, with the variable being
the location of the carb in the total length. This is lost when pods or equal length
stacks are used.

[Jeff Bennetts]

My bike that's shown on the home page today, built 12 years ago, only had the filter box removed and it took me weeks to sort it out to get it to run as good as a stock bike.

I've been around these bikes for decades and I'm fairly certain that I know how these carbs work, what they like and what they don't like.

Form follows function, always.

But, don't let me stop you.

Part of show and tell is the tell, since you have some experience with this how about throwing this guy a bone and give him some baseline settings?

[daves79x]

I thought I did.

Dave

[Jeff Bennetts]

I thought I did.

Dave

Yes you did Dave but I quoted and was referring to JR’s post, seems he has some experience with a similar setup.

[CBX-tras]

The fellow is altering too many things for aesthetics and killing the functionality.
There needs to be space at the opening of the velocity stack for fuel "stand-off" which it appears was eliminated.
While at the same time opening up the airflow that will dramatically alter the vacuum signal into the carb.
CV carbs work better sucking through a "straw" with restriction as opposed to a "sewer pipe" without any restriction at all.
These are NOT direct-lift carbs, don't treat them as such.

He should get Arties slides and needles mentioned on another post that were set up for pods.
Now, it will be one experiment after another before it runs as well as stock, usually throwing more fuel at it to disguise the issue. Then, wondering why his clothes smell after riding. (Unburnt hydrocarbons).

[Jeff Bennetts]

Well Paul a few more bones thrown your way, good luck with your project!

[Paul Van Oss]

Well guys I done the following.
Measured air intake side on the OEM top cover.
It measures 128 mm x 47mm so total air intake area is 6000 square mm.
Divided by 6 is 1000 square mm per carburetor.
I am going to make a restrictor plate and attach to the back wall of the air box.
I will make 6 holes each 36mm.
That is the same square mm intake area as OEM air intake.
I guess I made the sewer pipe into a straw!!
To fine tune and play around I can change the holes from I guess 32mm to 42mm. When I have the best performance I will weld a new back wall in my current air box and have it chromed again.
Still have the custom looks, which I like and still have the ease of carb removal.

[Paul Van Oss]

Just dawned on me that these carbs are not restricted at all as far as air intake volume.
36mm per carb air intake is larger then the internal diameter of the carb itself.
The only restriction is the OEM paper element filter????
What do you guys think?

[daves79x]

I think, good luck. What you are doing I’m sure can be jetted for, or fiddled enough to work with stock jetting, but really, why? A lot of work to end right back to where Honda was in the first place.

Dave

[Paul Van Oss]

Dave, I guess I like the challenge and the looks compared to the OEM system, plus the added advantage for not to have to tip the engine for removing carbs.

Paul.

[bobcat]

Different things matter to different people. More power is not always the goal.
Making something work that appeals cosmetically to some is as good as more
performance, sometimes better.
Even though it hurts performance, many like the looks and sound of the DG 6-1 exh.

Purists vs. modified and on and on, Cheer them on, it's a CBX !