Topic: New air filter for the 77/78 PD carbs

[dlhoulton]

Not trying to start anything here, just letting fellow CB lovers know that they have another option for a air filter/box. The people from "Steel Dragon" are producing a air filter for the 77/78 PD carbs. It's fashioned after the "Bread Box" style. There's is a rounded end instead of square.



Steel Dragon Performance are known for there machined velocity stacks for the Honda's and they put those into this bread box style filter:



They offer them in three finishes: raw/plain (you finish them the way you want) $130, Polished for you $155 and Powder coated $195. Plus shipping on prices above.

Here is an exploded view so you can see the inside:


I just got these so no performance reports. Just letting everyone know of the product.
No I don't work for them!!!

dlhoulton

[Stev-o]

That is beautiful, polished, right? Plz give us an update after installation.

[madmtnmotors]

Nice!

[scottly]

Hi-jack alert!!! I see you are in OK; any chance you can get your excellent machine out on the road and join in the third annual SOHC relay? They may be near your area very soon!
http://forums.sohc4.net/index.php?topic=118292.25

[750K]

Thats a thing of beauty, let us know how you get it working. I have a breadbox I like but due to the amount of rain we get in the PNW I'm switching back to the stock box just because...

I'll save the breadbox for a future project that wont see much rain.

[flybox1]

looks cool, but it also looks like it weighs 10lbs   
...and no rubber parts for proper sealing on the intake side?

[dlhoulton]

flybox1, the weight of the whole thing is 2lb 14oz. I thought they were going to be stamped steel but to my surprise the front, back and stacks are machined aluminum. Also as for sealing on the intake side the stacks have a grove in them and have a rubber "O" ring that seals when mounted on the carbs. Look close on the first two pictures and you can see them. Then each stack has three set screws for a total of 12 to secure them to the carbs.
dlhoulton

[Stev-o]

Don't think he bought for weight reduction so why is that a concern? Not going on a race bike...

[flybox1]

not a concern.  just an initial observation   
more of a concern for me would be the ability to seal on the intake side.

[Lee in Ottawa]

Pretty sweet, let us know how they perform.

[Stilltime]

Any update on this?  I don't see one listed on their site for the PD carbs...?

Chris C.

[lucky]

Nice product except be very careful with those mounting set screws.
They can actually bend or crack off a chunk of your carb inlet casting.

Make sure the 3 set screws are positioned to the strongest thickest part of the casting.

That is the only thing I do not like about that product.

[bollingball]

Is the filer the same size as stock? would a stock one fit?
Ken

[lucky]

Is the filer the same size as stock? would a stock one fit?
Ken

Do you mean filter?

[dlhoulton]

bollingball: Here is a side profile pick of filter on bike so you can see size if that is what you are asking. The first pick is with a stock air box and the second is with the new air filter. I am using "K" side covers on this "F" bike. The air box was for an "F" and I think that's why everything didn't line up or look right. You can see in the first pic when you mix and match components things start looking odd!



lucky: I'm already on top of the "set screws". They give you some short ones and I went to Lowe's and got a little longer (I got gorilla hands/fingers). There are three set screws on each (12 total) holding filter on, so I only set them just until they made contact and then ever so lightly gave a little more.

Stilltime: As for up date. On there site they didn't post that they had these. I contacted them because I had a question on something else I was working on and I had seen some one that posted they had gotten there two peace bread box filters. He told me he had this one (single, rounded end bread box style) and would I be interested. If you are interested in this style just contact Steel Dragon and talk with them. If you have to use me and these pictures for reference. They are members of this forum.
As for an update on performance, they are working out great. Here is a break down on what I have and done:
Bike is a stock 78 CB750F (no performance mods). From what I've read "F" bikes ran somewhat lean from factory.
Carbs are from a 77 CB750K.
Exhaust are Mac 4 into 2 turnouts with baffles (they were also for a "K" model)
Also have Dyna S ignition and coils.
As for the carbs the 77 "K" had stock: 115 mains, 35 slow and adjustable needle (on first/top notch clip)
For a stock 77/78 "F" motor and carbs it should run 105 mains, 35 slow and non adjustable needle (set at what would be first/top notch clip)
Because I went with the air filter and Mac exhaust I put in: 120 mains, 42 slow and adjusted needle to second from top notch clip (raised needle up one notch from stock position).

I also blocked off the upper half of the air filter for two reasons: 1. reduce air intake just a little 2. keep water out in event of riding in rain or cross wind issues. I read that pods and these bread box type filters can perform better with these simple mods.

Post is  a little long, but hope it answers some questions for anyone interested.
dlhoulton