Topic: 1977/1978 Airbox

[fendersrule]

So now that I'm tired of running pods, I have two complete airbox assemblies on hand. Only thing I need is:

1) Filter

2) Check jets to see if they are stock. If not, return them to stock.

I'll do 2) in the next couple days, but for the filter, where and what do you recommend to put in there? Something from K&N?

[Bankerdanny]

I just use a Honda filter.

Uni makes a reusable one for the 77-78, but I don't think K&N makes anything but the pods.

[flybox1]

only return your jets to stock (35/110) if you're running an exhaust with equal back pressure to the originals.
a paper filter will do you just fine.  if you ride in a dusty environment, you'll want to change it more often.
I prefer the cleanable K&N (part #HA-0100)

[Stilltime]

You could use the UNI 4055 in the stock airbox.

Or do a setup like this:

[Stilltime]

[Bankerdanny]

Where did that plastic adapter come from?

[Stilltime]

I designed it and had it 3D printed. Same mating geometry as stock airbox.

[fendersrule]

Thanks guys. I ordered the K&N filter. I put these on all my cars, and don't have a problem with the maintenance (about once a year or two, depending on how often I drive).

As far as the Jets, do you guys know what I should be expecting from the numbers? Would you guys remove the jets from al the carbs and check them, or just from one carb? Seems like they all "should" be the same.

I have the stock 4-into-4 exhausts.

But I'm guessing that the previous owner played with the jets being that that the pods are on the bike. Maybe not...at least I'm hoping.

[flybox1]

stock should be 35pilots/110mains, but if he had pods he SHOULD have gone up on the mains  possibly the pilot jets.
ALSO. depending on your carb type, you'll need to check if the needle clip was re-positioned or shimmed.  another possibility.
if you have the K8 pd carbs, they dont have adjustable needles clip positions, so the needle would have been shimmed with a small washer, or two.
if you have the K7 carbs, the needle clip can be adjusted.  note the clip position.
post up what carb type number is stamped on your carbs....

[fendersrule]

So I should be looking with washers as shims for this one?

[fendersrule]

Flybox, is this the right set of numbers?

[flybox1]

Yes.
and all you need to know is right here 
http://forums.sohc4.net/index.php?topic=71245.0

[fendersrule]

Is there a quick way to tell if they've been shimmed without pulling it all apart?



Ill post my findings on the jet sizes this weekend.

[lucky]

Is there a quick way to tell if they've been shimmed without pulling it all apart?



Ill post my findings on the jet sizes this weekend.

It would only have needed a shim under the needle if it had pods and a 4 into 1 exhaust.
Many owners are to lazy to do that. It takes patience and skill.

[flybox1]

sorry, no.  you have to pull the slides to see, but by then, you're half way done 

yeah, Lucky is right.  most PO's wouldnt have tuned it well enough to shim the needles. 
get your shim washers and grab a few beers....

[fendersrule]

I wouldn't need to shim since I'm removing the pods to put in the air box. Sounds like most likely there are no shims. Sounds like I just need to check the jets. Do I have to remove carbs to install air box?

[flybox1]

w/ the airbox, no need to shim. 
carbs stay on and you slide in the airbox.
-push all the boots in the airbox IN as far as they will go so you have a little more wiggle room.
-tilt the airbox back a tad, and slide it in from the left. 
- watch the mount plates and the hose clip on the top of the airbox.  they'll catch on the frame/harness/hoses/etc, and make it tough to slide in.
-  watch the carb boots against the lips of the carbs.  easy to mash or get them folded when snugging it up to the carbs.

[fendersrule]

Thanks Flybox. I'll check the jets on a couple carbs. If they appear stock, then I'll proceed with the easy installation of the airbox.

Can't wait to get better low-end performance and more consistent throttle response at high speeds....and more wind resistance.

[Lostboy Steve]

Where did that plastic adapter come from?

You should definitely sell those! I'll take 2.

[Lostboy Steve]

God, I need a 3d printer sooooo bad.

[hiljak]

Are you interested in selling your pods and related jets? I recently bought a 1978 CB 750 F. Bike came without any air box or carb filter of any type. I wil be going through the carbs soon. I know pods are not terribly expensive but I'd rather make use of your take offs than buy new....provided they're in good condition. Are they K&N? Please let me know if you're interested in selling and shipping them.

Sean

[fendersrule]

Hi Sean,

I would be interested in selling the pods. I'm not sure what brand they are, but if they aren't K&N, then they look/work just as nice (check out my build thread).

Right before my 200 mile trip, I did soak them in engine cleaner, and used some K&N oil on them. Basically, all you need to do is install them on your bike when you get them; no cleaning or oiling is necessary.

Personally, I like the looks of pods more than a clunky airbox. But what I feel that I am giving up for looks just isn't worth it for me.

Let me finish putting the box on (should be this weekend) and giving the bike a spin to see how it is.

If the jets are not stock, then you can certainly have them.

[fendersrule]

What probability would you guys give that the jets are not stock?

If they are not stock, are they basically an order-only item, or would any honda shop have them?

[flybox1]

What probability would you guys give that the jets are not stock?

If they are not stock, are they basically an order-only item, or would any honda shop have them?

its a crap shoot if your PO jetted for the pods  
some do and ride the bike, some dont and park it because it runs like crap.
if it was running when you bought it, id say he probably tried to jet it.
you can get jets from Dime City Cycles, or Sirius Consolidated....

[fendersrule]

Yeah.

My bike seems to run really good with the pods, so I'm assuming that it's rejetted. The only thing, is once you get going 55 MPH or above, it seems you have to put some more concentration on the trottle due to the increased wind from higher speeds. It's not "bad", but it doesn't seem to be as completely stable as it would be stock. And obviously, if it's really windy outside (it is in Boise, ID) at any speeds, then you can tell the powerband isn't as stable as it should be.

But for common, non-windy, around the town driving, the bike runs like a champ. It's just when you want to go on trips where you need to hold 55+ MPH over to,e, it's where the airbox seems to really offer an advantage.

So it's probably jetted, and looks like I'll need to order some mains and pilots. Can you pinpoint me to the right ones? I assume I'll need 4 mains, and 4 pilots?