Author Topic: Air Filters (Read 3201 times)

78 k550 · « **on:** June 22, 2005, 03:52:04 PM »

Hey All,
I'm ready for a new air filter. Should I by pod filter or just stick with the stock? I do like to ride and getting caught in rain will sometimes be a factor. Will I have any problem's with pod filters in the ran? It should open up my airway to give me more power. Should I need to rejet it? I have a 78 550K. I just got it so don't know if it is stock or been rebuilt. I would say it is stock from the look's of it. K&N didn't have it listed for my bike in the book.

Paul

Dennis · « **Reply #1 on:** June 22, 2005, 04:21:39 PM »

UNI may be available for your bike, I'm not absolutely sure.
I know they are available for the CB500K and I believe the 550 at least up to '76. Are the '77 and '78 the same?

Buffo · « **Reply #2 on:** June 22, 2005, 05:32:08 PM »

If you want more power buy a bigger bike. The amount of power you will gain from just adding a filter will be all but unnoticeable. Depending on the state of your power plant you might not notice anything. These bike dont need a ton of air. The machines that benifit the most from free flowing filters have large fresh air requirements.

1. If you go pods or ANY air filter that increases or decreases your fresh air intake you may need to rejet.

2. Riding in the rain will get more water on the outside filters making them cylinders run richer.

3. The outside filters will get more exposer to the elements and will get dirty (restricting fresh air flow) quicker than the niside ones. So clean them regularly.

Buy what you like. Remember it's your bike. Make it so you get a woody when you look at it!!

Don

jbailey · « **Reply #3 on:** June 22, 2005, 06:53:16 PM »

I installed a unifilter this year. Runs great. No rejetting needed.

TwoTired · « **Reply #4 on:** June 22, 2005, 07:05:09 PM »

The stock paper element filter is a pretty good fine particle filter. If you drive in a dusty environment, this type should maximize cylinder wall life of your engine. This type also provides a good deal of restriction to the air path, which gets worse as the trapped particle build up progress. Honda has tuned the carbs to accommodate the level of resrtiction this type provides.

Foam and gauze type filters have larger channels and are therefore not as effective at blocking tiny abrasive bits and preventing them from eroding cylinder walls. But, they usually provide less restriction for better flow. Les restriction reduces the barometric pressure difference across the jets, reducing their flow proportionately. To compensate carburetor metering adjustments can be of help.

The 78 CB550K probably has the leanest factory settings of all the CB550s. Were I you, I would try the UNI 4055 (I think) foam filter in the stock air box. This has a bit less restriction than the stock paper one. But, the carb idle screws might be able to compensate. If not, you can easily go back to the paper type.

How much more power are you looking for?

seaweb11 · « **Reply #5 on:** June 22, 2005, 07:16:39 PM »

Do a quick search at the top of your screen for "pods" there is TONS of advice on the subject.

KB02 · « **Reply #6 on:** August 06, 2005, 01:46:15 PM »

Sorry to drag up an old post, but I did have a quick question. I rebuild my 76 CB750F engine and put the UNI pods on it the intake. I have just barely got the engine running again and have onlty ridden a couple of times, but when starting it up, I have noticed that it comes off of choke VERY quickly, but won't idle at a good speed untill I have been riding it for about five minutes. I have been just increasing the idle speed with the screw adjuster when starting it up and then just dropping it down after a little bit to the normal idel speed (it likes it at around 13-1500 on the Tach). I have the factory jets in the carbs and have been thinking about re-jetting anyway to compensate for the extra air it's getting (factory 4 into 1 exhast).

Should rejetting help the cold starting any? I guess I won't know untill I've tried, but I thought someone here might have a little bit more insite into the question. I'll try searching under the "pods" heading above. Hopefully my ADD will hold out... it IS a nice day outside...

Buffo · « **Reply #7 on:** August 06, 2005, 02:35:21 PM »

I have different carbs that you but I would first get a dwell meter and set the idle and polit screws properly. This may straighten out your problems. A good carb sync never hurts.

Don

eldar · « **Reply #8 on:** August 07, 2005, 10:51:38 AM »

Keep the airbox. THere are no real benfits to the pods. They MAY bring in more air but they get wet, get dirtier faster, air flow is not as even and on.
The airbox allows for sother airflow which allows the air\gas mix to mix better. If you think you need more air, you can always drill holes through the air box on the bottom or top so the air still goes through the filter. If you do the sides it will not get filtered. Lately I have heard bad things about K&N. They do not seem to filter as good as they claim. Uni seems to be better. I would stick with the airbox however.

ofreen · « **Reply #9 on:** August 19, 2005, 11:23:44 PM »

[ Lately I have heard bad things about K&N. They do not seem to filter as good as they claim. Uni seems to be better. I would stick with the airbox however.

Quote

I have heard the same bad things about K & N filters lately, too. The scuttlebutt is that the K & N lets in more of the finer particles, causing accelerated cylinder and top end wear. I put a K & N air filter in my 750 way back when it had 10,000 miles on it, because I saw that the K & N cost the same as the OEM filter and was reusable. The bike now has a little under 98,000 miles on it and still has the stock airbox. In the meantime, I lived at the end of a mile long gravel road for 6 years, and am now at the end of a 1/3 mile gravel road for the last 5 years. I have to clean the filter a lot more often than K & N's 25,000 - 50,000 mile recommendation. The bike still uses virtually no oil. I change the oil every 3000 miles, and it is never down more than a cup. I figure that with all those trips up and down those dusty roads, if the K & N filter let in harmful particles it would be showing up in increased oil consumption because of top end wear. It hasn't, so I am skeptical about claims against K & N filters. Others may have different experiences, of course.

Greg

hymodyne · « **Reply #10 on:** August 20, 2005, 07:31:26 AM »

I had pods, but took them off. its easier to tune with the breathing system in a predictable or at least previously tested condition.

hym

rsmith550 · « **Reply #11 on:** August 20, 2005, 06:13:34 PM »

www.oldbikebarn.com

74cb750 · « **Reply #12 on:** August 20, 2005, 09:17:55 PM »

The main problem I have with the OEM airboxes on my cb's are that the airbox to carb funnels dry up and harden. Making the task of working on the bikes very difficult. Currently both my cb750's ahve pod filters and haven't noticed any difference in power etc. michel

chrometank · « **Reply #13 on:** August 21, 2005, 05:24:43 AM »

Ive got velocity stacks on mine ,just because i like the look.They have filter foam behind the brass gauze.Ive had the box then the pods and now these,and theres no difrence in power between them,the stacks are just as smooth as the box

TwoTired · « **Reply #14 on:** August 21, 2005, 08:56:08 AM »

Quote from: chrometank on August 21, 2005, 05:24:43 AM

Ive got velocity stacks on mine ,just because i like the look.They have filter foam behind the brass gauze.Ive had the box then the pods and now these,and theres no difrence in power between them,the stacks are just as smooth as the box

Um, don't take this as any kind of attack, I'm just trying to gather data.

When you say the is no difference in power do you have any performance numbers to compare before and after? Something like 0-60 times and speed, 1/4 mile times and speeds.
What about fuel mileage? Any change there?

I'm fine with what the bike feels like. It's just that it is difficult to make accurate comparisions that way.
Cheers,

cd811 · « **Reply #15 on:** August 21, 2005, 09:29:54 AM »

I like pods myself
easier to work on carbs and cleaner look
but i'll be your call
I really don't think you'll gain anything like hp
9 out of 10 carbs need rejet
the best deal I found on pods...crc2onlinecatalog.com

chrometank · « **Reply #16 on:** August 21, 2005, 03:36:02 PM »

Hey TwoTired,No i dont do any tests as such,but i live on sydney harbour with some lovely hilly roads all around me.After having this particular bike for so long i can just feel when its running really well,When i first put on the V.S i was getting to much air so I put in the filter foam,it was better but still a bit throaty.so i oiled the foam and now its perfect.But exactly the same pulling power as the standard box .No rejetting required and still getting nice tan plugs.just my observations

liquidplumber · « **Reply #17 on:** August 21, 2005, 04:15:54 PM »

Doesn't the stock air box help support the carbs? Looks like with the pods, the carbs are just hanging by the intakes. Is that something to be concerned about?

chrometank · « **Reply #18 on:** August 21, 2005, 04:20:22 PM »

hey plumber,you can grab my stacks and rock the bike!Pretty solid

TwoTired · « **Reply #19 on:** August 21, 2005, 06:36:17 PM »

liquidplumber,
You're right, the airbox does add support for the carbs.
When the rubber intake couplers are new and supple, carb support and shake is a factor. It seems, however, as they age, the rubber gets very hard and take a set. So, they support the carbs pretty well on their own.

chrometank,
Thanks, for your info. I know what you mean by feeling the power. The ride just after a tuneup usually makes for a very wide grin.

I'm not a big fan of pods or stacks for a road bike. But, with the right set up, I'm sure they can allow the engine to perform well. I think I would still be concerned about riding in crosswinds or rain, though. But, that's just me, I guess.

Cheers,

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Author Topic: Air Filters (Read 3201 times)

Buffo

Buffo

eldar

rsmith550

cd811