Topic: Soda Pop Pod Filters

[BostonCB]

I've seen a lot of discussion on re-jetting carbs, but this is a slightly different take on the issue. I tore apart my cb550k last winter to do a lot of cosmetic work and replace some worn and rusty parts. I ordered a Mac 4 into 1 and, as an afterthought, ordered a set of Uni pod filters.

I didn't do the research I should have done. As you would expect, when I put everything together I had a beautiful bike that ran like crap. I figured I'd have to go ahead and re-jet it for the filters, but then I started thinking about that.

Most of my riding is around town. I'm seldom at full throttle. It didn't make sense to me to tune my bike like I was racing it and I thought I'd best put back the airbox. But then I had a revelation! I sliced a plastic soda pop bottle into four rings, each slightly short than the depth of the pod filters. I cut each ring so that I had four spirals of plastic. I wound each one tightly, inserted them into the four pods, allowing them to expand inside the pods. My thought was that this would choke back the airflow and restore the performance of the engine.

My bike runs beautifully now, plenty of power. Has anyone else tried this? In the end it was much cheaper than a new airbox (the rubber was cracked on the old one) and it gives the bike that cafe racer look without compromising its performance as a daily driver.

[mkramer1121]

I'm waiting for the story where you suck the plastic into your carbs....

[Bodain]

A few years ago I tried something similar. I was looking for a change or improvement. So I cut up some foam and put it in each filter. It was actually pretty tight. Seemed to be a small improvement. Then two days later I leave the house on it. Suddenly it's like the throttle is sticking. I hit the kill switch real quick. Hmmm... I don't really see anything wrong. I start it up. The engine instantly revs to very high RPM without any throttle. Hmmmm...

As you can guess. One of the foam pieces I had jammed in the pod was sucked into the carb and holding the slide open. I pushed the bike home, about 3 blocks , then found it.

Boy did I feel stupid!

[HavocTurbo]

A lot of older guys used to get black foam and use black fabric tape to block air from the outside.

As long as the plastic spirals arent able to shrink inside the diameter of the inlet you should be fine.

[Inkscars]

Hrmmm.......I'm thinking about it.

[HavocTurbo]

Still haven't gotten yours?

[Inkscars]

Yea I have, and I've jetted. My uni's have a spring in them that keep them from collapsing. I could put some sort of material to block it under those so they don't get sucked in...
It's temporary and wouldn't mess anything up. I may try it.

[HavocTurbo]

First take some masking tape and start to cover your filters a little at a time on the outside until it runs how you want.

Then remove the spring and cover that with really thick fabric tape across the coils to the outside measurement and put it back in.

Then remove the outer tape and voila!

Instant rat carb rejet. 

[bikerbart]

heres my answer,actually worked great.

[TwoTired]

My Eyes, My Eyes, the Goggles, they do nothing!

Should've left the labels on the cans for extra visual appeal.  That way, when they drool at thinking of the food product, you can think they are really salivating for your bike.


 

[mrbreeze]

My Eyes, My Eyes, the Goggles, they do nothing!

Should've left the labels on the cans for extra visual appeal.  That way, when they drool at thinking of the food product, you can think they are really salivating for your bike.


 

......ummmmmmm!!!!!!! Nice bike!!!!....No!!!!....Campbell's Tomato Soup!!!

[razor02097]

heres my answer,actually worked great.

.....just.....wow..... you know covering up the problem won't make it go away...

[mrbreeze]

I'm kinda on the top of the fence with this arguement.I understand where Lloyd is coming from as far as Honda designed it that way for a purpose and you will have probs with turbulance and blah,blah,blah. Anyone that has had to pull the stock airbox and reinstall to clean carbs knows what a PITA it is to hook that bugger back up and in no way looks as cool as pods or stacks.It took me awhile but my bike runs great all day long with the pods and 4 to 1 exhaust. The guy I work with owns an 06' Yami R1 and told me what he has to go through to get his airbox off and back on. I think the plastic soda bottle thing kinda sounds do-able but I would make sure it is held in place to where it couldn't possibly un-do itself and get sucked into the carb. I could see foam doing that.

[RichPugh]

I tore apart my cb550k last winter to do a lot of cosmetic work and replace some worn and rusty parts. I ordered a Mac 4 into 1 and, as an afterthought, ordered a set of Uni pod filters. I didn't do the research I should have done. As you would expect, when I put everything together I had a beautiful bike that ran like crap.

I've been told over and over that an old CB550K with pods and a simple 4-into-1 exhaust should NOT NEED new jetting, only a good mega cleaning of the carbs and cleaned or new stock jets, etc., maybe a simple rebuild kit

Welp, I am pure proof that this combination (pods and 4-into-1 exhaust) with stock jetting works lovely.

I got the bike in running condition but the petcock leaked, one of the bowls leaked if you left the petcock on, it would idle lovely and rev up in neutral but it wouldnt rev well or accelerate well under load conditions (i.e., actually just riding the bike and not just revving it up sitting still).

I decided to pull the carbs off (and stock airbox), remove all the old slow/pilot jets, main jets, floats, float pins/seats and mixture screws, have the naked carb assembly ultrasonic cleaned (ran it through 4 times), rebuilt with K&L carb kits with stock 38/100 jets (I used every part in the kit except the needles), set the floats to 22mm, adjust the mixture screws to 1-1/4 out, toss them back on with four 35mm pods, new NGK plugs, cut the ignition wires back and re-fitted to the plug ends, new tank of high octane gas... VOILA! She runs like a champ... idling, light throttle, mid throttle, WOT... so good. Plugs are all burning lovely tan. Forget all the woahs... I have a stock jetted bike and it screams.

(shameless pic hijack LOL)

[razor02097]

Its simple... Honda designed the stock airbox and exhaust to produce max power and torque from idle to redline.  You may say BS but think about this... they also had to design a system that would work in a large range of temperatures and altitudes also!  The conundrum just got worse...

Whenever you modify the stock setup you will loose somewhere if you do not compensate with jetting, timing, what have you.  

You talk about a PITA... I carry several jets for my RM250 cause it either runs ballz out or like crap.  Different temps, humidity, gas mix ratio, age of gas, condition of air filter, age of spark plug all contribute what jet I will be using that day.  Hot days jet leaner cold days jet richer.  I'm getting good at pulling the carb though  

The airbox is a pain in the arse but you have to remember that the rubber becomes more like plastic with engine heat and age.  I will admit it does suck but it takes me the same amount of time to pull my cb650 carbs as it does to drive to the shop and pull my wallet out for someone else to do it.  




If pods work for you then freekin awesome.  If they don't you should try to get em to work.  They may never work right.  Its part of form over function mentality.

[RichPugh]

You talk about a PITA... I carry several jets for my RM250 cause it either runs ballz out or like crap.  Different temps, humidity, gas mix ratio, age of gas, condition of air filter, age of spark plug all contribute what jet I will be using that day.  Hot days jet leaner cold days jet richer.  I'm getting good at pulling the carb though  

I dont ever want to have to maintain a carb'd 2-stroke LOL... The 550's dont have a fuel enrichment pump or any other compensating fuel system than the design of the carbs. You can tweak (set/adjust) the Keihin carbs to easily run pods and 4-to-1 exhaust with new clean stock jetted carbs. It's lovely.

[bikerbart]

C'mon Two Tired its kinda cool looking and you know it.And by the way,they are Van De camps 7 ounce bean cans.That wasnt the bike backfiring.

[Laminar]

Someone else on here did this same sort of thing - they cut a triangle of aluminum and put it inside each pod, restricting airflow.

[Laminar]

C'mon Two Tired its kinda cool looking and you know it.

What's that saying about ugly babies? A face only a mother could love...

[TwoTired]

The 550's dont have a fuel enrichment pump or any other compensating fuel system than the design of the carbs. You can tweak (set/adjust) the Keihin carbs to easily run pods and 4-to-1 exhaust with new clean stock jetted carbs. It's lovely.

I find the claim difficult to believe.  Honda used the same style carbs on the 500 and 550K/F models.  The carb differences for the models vary only in the jetting and adjustments among models.  They all used the same air filter.  Only displacement and exhaust changes were made to the machine's engine characteristics.  If what you say were to be believed, then all the differences Honda made to the carb's metering were for naught.

I predict we'll find out that the Butt dyno you are using, is not quite as accurate as the ones Honda used to tune the bikes with changes to carb fuel metering.  There is also the fuel economy aspect to use as comparison for properly tuned, but not reported.

Got any Dyno printouts to back your claim?  Did you have any seat time on the same bike in the stock configuration, with which to compare against?  Even if your bike runs well, how can you claim it runs as well or better than stock?

Another point I would like to make is that you replaced Honda parts inside the carbs, with ones from a different manufacturer.  How do you know the parts specs, dimensions were the same?  How do you know it wasn't a happy coincidence that the part changes didn't happen to be just what you needed to have your engine run well? (Assuming it does run well, make the same power, and have the same fuel efficiency as the stock bike.)  Were the jets really the same diameter as stock, or just stamped that way?  Did the K&L kit have replacement emulsion tubes? If so, did they have the same air bleed hole placement and size as the stock ones?  Was the throttle valve orifice the same or larger than stock?

Further, why would you assume a 35mm pod from all manufacturers would have the same air flow/ restriction characteristics?  Or, that they would be similar to what the stock air filter arrangement provided?

I'm thinking your pure proof has some variables in it. 

I do agree these Hondas are lovely, though.

Cheers,

[TwoTired]

C'mon Two Tired its kinda cool looking and you know it.And by the way,they are Van De camps 7 ounce bean cans.That wasnt the bike backfiring.

 

I gotta ask...
Did you clear coat the cans to keep rust at bay, or just add their replacement to the routine maintenance schedule?
Have you found that the seam orientation of the can changes the engine state of tune?  Or, will "seams out" work as well as "seams in"?

Beans, eh?  That's food for thought...

[razor02097]

I bought my bike stock except for the guy took out the baffles in the exhaust... I would have loved to have the stock exhaust... I spent a long time tuning and fiddling with the carbs to get even the more restrictive gixxer mufflers to work. 

I don't know how accurate my "butt dyno" is but I know my butt dyno says that I still am too lean at WOT.  Really my bike doesn't live there but I'm happy with it for now.  I realize every modification requires some sort of fiddling with since these bikes can not compensate by themselves... only fuel injected motors can do that and only to a certain point.  Past that they run bad and start throwing codes and tantrums.

Same think applies though.  If you run your bike in super cold weather the engine will run leaner then if you run in super hot weather.  On an 800lb street bike with 60-70 HP its not as noticeable but on a 200lb 45HP racing dirt bike its definitely noticeable.  How does this matter?  I guess it doesn't... so long as you like how your bike performs then you got nothing to worry about.  If not then that is why we are here for ya 

[Laminar]

I've seen plenty of people go from pods back to stock airbox and love it - I'd like to see someone go from pods to stock airbox/appropriate jetting and NOT love it.

I'd also like all of the people talking about how their bike with pods runs "perfectly" list their point of reference - did the bike also run great with the stock airbox?

Someone who has only ever ridden a bike when it had pods installed wouldn't know that it shouldn't have that flat spot, that slight hesitation, that different throttle response, or that power dropoff, and would just assume that it "runs perfectly."

[billybobobrain]

if honda designd the stock air box and exhaust for max hp then why did the honda racing teams not use them........ ..... ..... .....

Because honda didnt do that. They needed to make money on the bike, so they had to find a good compromise between performance, drivability, and cost just like every other manufacturer out there.

Furthermore they designed it to work with the stock components bore/stroke, carbs, and cam profile, for city and highway driving. dont fool yourselves into thinking that stock is supposed to give you the best performance.

My Eyes, My Eyes, the Goggles, they do nothing!

Should've left the labels on the cans for extra visual appeal.  That way, when they drool at thinking of the food product, you can think they are really salivating for your bike.


 

 

[Laminar]

Furthermore they designed it to work with the stock components bore/stroke, carbs, and cam profile, for city and highway driving. dont fool yourselves into thinking that stock is supposed to give you the best performance.

Like I said - show me someone that went from pods to stock airbox/proper jetting and hated it.

Those Honda racing teams that didn't use the stock airbox also had more resources at their hands than the typical garage wrench-turner, and they had better methods of engine testing than the ultra-reliable plug chop.