Topic: So, you want to run pods?

[PeWe]

Here how my old unmarked conical pods looks like. Beside K&N oval for my Mikuni VM29.
Both not that bad inside. K&N has  plastic lining like short stacks as Mike mentioned.

The new K&N (photo) I bought on sale 2022 here just for sure. Ca: $200 US instead of ca: $300US

My K&N pods on my Mikuni TMR were tricky to get the clamps right after 5-6 years of use.  Clamps  not where they should, pod almost glided off the carb.
I found a fix by adding a plastic ring so clamp cannot glide. Pods to ve used a few more years.
I have a new set for future use. See photo.

The conical pods were first used on my Smoothbores, later on K6 stock 086A carbs. The rubber shrank...

I guess the price will rise even more.
My set to the Smoothbores cost around $150US  2013 from eBay UK.
Double less than 10 years later.

[Tracksnblades1]

Good post PeWe,
How long are the velocity stacks in the oval variant..?

In 1982 the ovals were advertised with “built in” velocity stacks..
I still have a set of 4 that I had modified by sliding them on a wood dowel (closet hanger rod)
freezing them and power saw trimming a 1/16” of an inch or so off of the rubber. Effectively allowing
them to fit closer to the F1’s carbs so the clamps were in the correct position on the Keihin’s shorter filter spouts.

Similar to Don R’s more efficient method he pictured in his turbo or Weber carb post with the chop saw..I don’t think chops saw were the norm in 82. I had to use the radial arm saw…😜

These ovals only had 1 or 1.5”  built in velocity stacks. So when install they effectively shortened the F1’s good power range by moving the climbing on the pipe (cam)power band up closer to the redline.

Even after my uncles shop vac and flour test example 😳,  I still ran them for a short while after rejetting. Eventually removing them after getting caught in several downpours washing the oil and cotton gauze off the outer two from trying to shield them will my pants…They fail more than just the white flour dust test now..🤫🤫

[PeWe]

I measured one from my new not used set for my Mikuni TMR32, 54mm dia fittings.
22 to 25mm from front.
The old conical very close, 22mm.

The pods on 1:4 sit very close to frame. I like the long intake runners. There are shorter for the carbs to order. I prefer lower rpm torque for street use.

If separate pods are an issue or design only.
An "airbox" can be mounted around them.
K&N filter for stock airbox no longer produced.

[kerryb]

On the subject of oval pods, here’s a hypothetical situation.
This custom bike sounds fabulous in the video I saw.  It rode great to a show 25 miles away, but on the return trip it began to falter, missing, stumbling.  Finally home with a trailer.  Seems it fouls the plugs. 
   Here’s the interesting part, derived from the questions I asked;  CB450 motor, mikuni carbs, oval (k&n?) pods.  it was tuned and ran well without the pods, but then the pods were put on to make it more complete for the show. 
   If it was tuned for open-throat carbs, would pods create enough extra vacuum to run too rich, thus fouling the plugs?
   I’ll be removing the carbs and inspecting the plugs this Friday.  Planning to inspect the carbs carefully for evidence of dirt, then cleaning them and reinstall.

[carnivorous chicken]

I'm playing around withr eplaced my pods with a stock airbox set up at high altitude and Scottly suggested I add my two cents here since the bike was running much better with pods before I installed the airbox.

I'm in Mexico City, so about 7500 feet elevation. 1976 CB550F1. Not sure of the make of the pods, but I can add a photo. Jetting is 38/100 (38/98 is stock, so assuming a PO rejetted). No markings on the jets, so assuming they are aftermarket. I should add: the o-rings on the jets are old, and they don't hold the jets in place, so assuming there might be some gas getting by them as well. Idle mixture screws 1.5 turns out. D7EA plugs.

Bike runs well with this set up, with great response and no flat spots. At 1200rpm idle it chugs a little and I get it a quick blip before taking off.

Switching over to the stock airbox, the bike idles smoothly and more quietly, but bogged at around 4krpm. I will likely switch back to the pods for now, but look at replacing jets and moving the needles to lean out the mixture. I'll use the formula Hondaman recommended me: 1.2% per 1000 feet of elevation -- so at 7500 feet + 9%. Stock main is supposed to be 98, so around 88.

Thought I would respond to this post with an update -- spoiler: looks like the stock airbox is going to work.

Had a broken float tower when I wanted to switch out my jets (bumped it), so the bike sat since March while I waited to go to the USA to pick up a spare rack of carbs. Wound up getting an insanely clean set that must have been rebuilt -- just spotless. Went through them anyway, cleaned them up outside, and replaced the stock #38 jet with #35 (there was no close step down in size from the stock #98 so I kept that). I also dropped the needle one spot (069As on the 550Fs are second from top, so one is all there is). Got the carbs in, got the airbox back together and hooked up, dropped in a new filter, checked the float level, and fired it up this morning. Went for a quick cruise, got the RPMs up and it revved cleanly up to 7000RPM (didn't take it any higher). Idled nicely at 1200 but the idle came up a little after cruising around so I dropped it back to 1200. Going to sync the carbs tomorrow and give it a full tune up, but I think this is going to work out.

IF anyone wants more details they're here: http://forums.sohc4.net/index.php/topic,193106.150.html