Topic: cb400 up and running, but now I need help!

[JHansen]

Hi,

OK, tonight, I got my freshly rebuilt motor up and running. It's running like a champ. Good oil pressure, no bad smoke/noises, nice and smooth.

The only hitch during installation was that I pretty much destroyed the plastic air chamber that sits between the air filter housing and the carbs. It's not going on the bike, period. Can't get the 4 rubber grommets around the carbs. Spent 2 hours trying tonight, with the assembly both on and off the bike, it's not going on there!

So, since I have an air filtration delema on my hands, what not fix it with something I would rather have, right?

I have seen several CB's with individual "pod" small air filters attached to each individual carb. I think most I've seen are made by K&N. I think they look right on the bike and I want some! What are these called? Where can I obtain them? My local Pep Boys? On line supplier?

Lastly, any running issues if I decide to switch the these air cleaners?

Please help! I want to run this thing, but can't till the air is filtered!

Thanks~ John

[heffay]

throw pods on it... you want to, the bike wants you to and you'll have to rejet most likely but it can be done.  (fairly easily i might add)  unless you have to take the carbs off a million times then it will start to suck.
                                                 

[JHansen]

You are right... I want to. Where can i find these pods?

Thanks! John

[heffay]

google pod filters cb400f or something of the like... better yet, do that in ebay!  most of my parts come from ebay and i've never really been stung.


edit:  do many searches... filter cb400, air filter cb400f, pod filter cb400... you see how i left out the f sometimes or changed pod to air... it really does help.  or even something like honda air filter or motorcycle air filter

[TwoTired]

Yes, individual carb filters or "pods" is the easy way around the air box shoe horn.  Measure the diameter of the carb inlets, and get the size that will fit onto them.
But, don't forget that the carbs are now jetted and adjusted for use with the stock air filter setup.
Be prepared to change the main jets, slide needle settings, idle air bleed screws and perhaps the slow jets, too.  Finding the right carb settings can take far longer than learning to install the stock air filter.  So, be prepared.

The hardest mixture change is the throttle valve cutaway for 1/8 throttle settings.  Grinding or adding metal to the carb's slides is pretty tricky and I've read on this forum where people with 400s and pods and pipe changes never get their bike to transition well from 1/8 to 1/4 throttle settings.

Engineering changes sometime have a "ripple effect".

Best of luck!

[heffay]

Yes, individual carb filters or "pods" is the easy way around the air box shoe horn.  Measure the diameter of the carb inlets, and get the size that will fit onto them.
But, don't forget that the carbs are now jetted and adjusted for use with the stock air filter setup.
Be prepared to change the main jets, slide needle settings, idle air bleed screws and perhaps the slow jets, too.  Finding the right carb settings can take far longer than learning to install the stock air filter.  So, be prepared.

The hardest mixture change is the throttle valve cutaway for 1/8 throttle settings.  Grinding or adding metal to the carb's slides is pretty tricky and I've read on this forum where people with 400s and pods and pipe changes never get their bike to transition well from 1/8 to 1/4 throttle settings.

Engineering changes sometime have a "ripple effect".

Best of luck!

I said that already:  "unless you have to take the carbs off a million times then it will start to suck."
 

[Dusthawk]

WWW.SANDLCYCLES.COM

I got my pods from these guys. Real great pods!!!

I got them through E-bay, seller name is Chitown-Choppers

do a search, it should pop right up for ya

Peace,
Jeff

[tsflstb]

These are the cheapest I've seen ($8.95 ea).  I'm not sure how they compare to K&N.

Go to 'fuel system parts'...'air cleaners'...'pods'...I think the 400 takes a 35mm.

http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

[supersport_CB400F]

If you going to be using pods and not the stock system and you’re wanting to sell your original air filter drain tube let me know, it's the part in the diagram ringed in blue, let me know I need one…… cheers

[Gordon]

Here's my prediction:

You'll shell out some money for the pods.  You'll shell out some more money for larger jets to accommodate the increased airflow (both main and idle).  You'll pull the carbs several times a day every weekend to change the needle setting trying to get the correct mixture.  You'll pull the spark plugs several times a day each weekend checking to see if you have the right mixture.  You'll buy a new set of spark plugs at least once because all the removing/reinstalling will destroy the crush washers on them.  You'll buy a new set of main and idle jets because the last ones weren't the right size.  You'll buy a new set of carb gaskets and o-rings because all the removing and reinstalling will destroy the old ones.  You'll strip at least a couple of float bowl screw holes because of the soft metal.  You'll buy a carb synchronizer because all the removal and adjustments will throw the carbs way off balance (you should get one anyway).  You'll become an expert at removal, rebuilding, reinstallation and synchronizing of your carbs, and then six months from now you'll go back to the stock airbox setup with stock jetting because you could never get it set right with the pods, you'll gain a new understanding and respect for the work the Honda engineers did 30 years ago, and you'll be happier than ever.   

I'm not saying you shouldn't do it, that's just my prediction. 

[JHansen]

Gordon, you might be correct but you left out one thing. All the questions I'll post because I don't have any experience in tuning carbs with aftermarket filters. I'll be learning as I go, so it won't probably be six months, will probably be a year! But isn't that why I have SOHC4 forums for? So I can ask questions, advice, and occasionally, whine?

No disrespect for the Honda engineers of ages past, and if I had a new airbox with good rubbers on it, I'd probably use it.

On second thought... are you referring to the same Honda engineers who designed that crummy and asinine cam chain adjustment mechanism on my 400 that operated primarily on voodoo magic? Those fellas?

Just kidding, the motor is great, and most engines have a few chinks in their armor.

John

[supersport_CB400F]

Here's my prediction:

You'll shell out some money for the pods.  You'll shell out some more money for larger jets to accommodate the increased airflow (both main and idle).  You'll pull the carbs several times a day every weekend to change the needle setting trying to get the correct mixture.  You'll pull the spark plugs several times a day each weekend checking to see if you have the right mixture.  You'll buy a new set of spark plugs at least once because all the removing/reinstalling will destroy the crush washers on them.  You'll buy a new set of main and idle jets because the last ones weren't the right size.  You'll buy a new set of carb gaskets and o-rings because all the removing and reinstalling will destroy the old ones.  You'll strip at least a couple of float bowl screw holes because of the soft metal.  You'll buy a carb synchronizer because all the removal and adjustments will throw the carbs way off balance (you should get one anyway).  You'll become an expert at removal, rebuilding, reinstallation and synchronizing of your carbs, and then six months from now you'll go back to the stock airbox setup with stock jetting because you could never get it set right with the pods, you'll gain a new understanding and respect for the work the Honda engineers did 30 years ago, and you'll be happier than ever.   

I'm not saying you shouldn't do it, that's just my prediction. 

Gordon what are you the  “SOHC bloody fortune card reader”…..get the pods and sell me you parts take no notice of him JH , those pods will look so cool on your bike the 750/550 guys know nothing about cool looks or the mighty 400F or the rather less 350F 

[JHansen]

Biffta,

I'm fine with that, let me pull it off the bike and clean it up (actually, I need to make sure it's even on there). E-mail me your e-mail address and we'll get it all setup-

Best, John

[DeLuxe]

Hey tsflstb, thanx for the tip on where to get the pods. I got 4 for the price of one here in Australia, and that included airmail from the US!
Um, I'm no expert, but re-jetting? Why? (I know there's probably an algorithm that explains why, but empirically, everything seems to work fine).
The site that I bought them from (CRC2) states that "Re-jetting is required for most applications. Twins and 550 and smaller Honda fours usually do not typically need jetting."
So, experts; should I start stuffing around and get sucked into the vortex, or just leave it as is?
Anyway, just wanted to thank you.

[dave75]

I have a CO-OP working for me at work.  He is a Georga Tech engineering student on some "build a fuel efficient race car" competition or something.  We got into a discussion on fuel injection.  He showed me a site at megasquirt.info that is the "poor man's version" of fuel injection.  For somewhere around $300 - $400 it looks like you could fuel inject just about anything... which I would be tempted to try should my CB400f ever get unmanagable (carbs that is..).  Only issue would be coming up with a strong enough electrical system to accomodate the high pressure fuel pump and electronics.  The plus side (and down side) is that you could change all of your settings at will...... endless variation.

Dave

[red91sit]

I have a CO-OP working for me at work.  He is a Georga Tech engineering student on some "build a fuel efficient race car" competition or something.  We got into a discussion on fuel injection.  He showed me a site at megasquirt.info that is the "poor man's version" of fuel injection.  For somewhere around $300 - $400 it looks like you could fuel inject just about anything... which I would be tempted to try should my CB400f ever get unmanagable (carbs that is..).  Only issue would be coming up with a strong enough electrical system to accomodate the high pressure fuel pump and electronics.  The plus side (and down side) is that you could change all of your settings at will...... endless variation.

Dave

I"m sure there are other alternators that would be swappable onto our bikes? or maybe a rewind?  If you do go fuel injected, get a wideband o2 sensor too, some of the fuel management systems have a self tuning setup.  Put in a basemap, and it reads inputs from your o2 sensor to get the optimal a/f ratio at all times.  I'd love to see just how good of fuel mileage you'd get with this setup as well.