Topic: **Need help with POD filters install** Bike shuts off at high rev's

[Jahaaji]

Good day all,

I am in need of some help regarding POD filters that I installed on my 1978 Honda CB550. Over the winter I decided to spice up the 550 by turning it into a mini cafe racer keeping all stock except for the handle bars, shocks & removing the stock air box and replacing with UNI POD filters. All went well except now that I've installed the POD filters, I noticed at high rev's the bike shuts off. It seems like air is is escaping and the bike shuts down.

I also cleaned the carbs during the winter but didn't touch or replace any jets. I'm kinda stumped here...... Do I need to sync my carbs or would it be easier to go back to stock air box?

Please help

[Bankerdanny]

Nice looking bike.

If it shuts down like someone hit the kill switch then it isn't fuel related. A fuel problem will manifest with hesitations and slow loss of RPM's as fuel is used up.

An ubrupt shut down is 99% likely to be electrical. Double check your connections at the coils, points, ignition switch, and kill switch. It could just be a coincidence that this started happening after the chaneg to pods.

[Jerry Rxman Griffin aka MuthaF'er]

Yeah, and you ain't gonna run pods with stock jets either. Needs more gas/bigger jets. Carbs ALWAYS need to be in sync but that wouldn't cause your problem. Your air flow has less restriction with pods and that exhaust, air is flowing more freely = more air flow = needs more gas to keep the air fuel ratio correct. Good luck. Pods can be a pain but can work.

Bike's looking good. Hope you get it sorted out. Maybe ask a specific 500/550 pods vs jetting question for the right guys to notice and provide that specific feedback.

[dave500]

save yourself a lot of bother,put the airbox with a new filter back on.

[bjbuchanan]

Nice looking bike.

If it shuts down like someone hit the kill switch then it isn't fuel related. A fuel problem will manifest with hesitations and slow loss of RPM's as fuel is used up.

An ubrupt shut down is 99% likely to be electrical. Double check your connections at the coils, points, ignition switch, and kill switch. It could just be a coincidence that this started happening after the chaneg to pods.

I agree with bankerdanny. You don't have to have the bike rolling down the road for it to shudder and die at high rpm it can do it idling just fine. Abrupt cutoff is electrical normally. How long did you have it running without moving, could have overheated it, just a thought

If you want to do the necessary tuning adjustments, which can take a lot of effort with still minimal sacrifices keep the pods. If you would like an all around runner that you can more or less keep the stock jets and positions put that airbox back on.

The bike is sharp. IMO if you have the stock sidecovers in place then the exposed cool factor of pods is pretty limited really and I think the airbox takes the space up better. I would bob the rear fender with something I picked up on the cheap from the board. It would tighten and tuck the bike up nicely I think. Stock clocks look good with that setup IMO

[iron_worker]

I have a feeling what is going on here is poor description of the actual issue.

IW

[Duke McDukiedook]

Put the stock airbox on to determine what the real problem is and keep it on is my recommendation.

[Jerry Rxman Griffin aka MuthaF'er]

I have a feeling what is going on here is poor description of the actual issue.

IW

+1

[Jahaaji]

I think I'll try putting back the stock air box to see what happens. To be a little bit more specific, when I give the bike throttle it sputters a bit and eventually cuts off

[Jerry Rxman Griffin aka MuthaF'er]

Doesn't sound electrical to me. Jets.

[Retro Rocket]

save yourself a lot of bother,put the airbox with a new filter back on.

Exactly.....   For the noobie, these bikes were engineered to run with the airbox, yes, some carbs respond well to pods but the old SOHC Honda's don't, Thats why they have  properly designed velocity stacks {for their day} even most of the guys that think their bike runs well or betterwith pods really doesn't have a clue, more induction noise does not equal more power....   Flame away....

[Rigid]

Peas have pods, they are removed before use.  Most scifi movies I have seen have escape pods.  They are only used in extreme emergencies in the movies.  From this evidence, i would say pods are bad.  I have purchased and installed over 200 of them because they look cool and the chop bob crowd loves them. My point is? I don't have one. 

[scottly]

Good day all,

I am in need of some help regarding POD filters that I installed on my 1978 Honda CB550. Over the winter I decided to spice up the 550 by turning it into a mini cafe racer keeping all stock except for the handle bars, shocks & removing the stock air box and replacing with UNI POD filters. All went well except now that I've installed the POD filters, I noticed at high rev's the bike shuts off. It seems like air is is escaping and the bike shuts down.

I also cleaned the carbs during the winter but didn't touch or replace any jets. I'm kinda stumped here...... Do I need to sync my carbs or would it be easier to go back to stock air box?

Please help

Looks to me like your carbs are sagging at the rear, possibly causing air leaks at the boots at the front. The stock air box provides some support at the rear of the carbs, but this is often overlooked when pods are fit.
Yes, the easiest thing would be to go back to the stock airbox.

[Stev-o]

Need more info. Did the bike run great before you put the pods and exhaust on? 

You've changed your intake and exhaust but not touched your jets, that equals problems.

You cannot properly clean carbs without cleaning the jets. 

[Jerry Rxman Griffin aka MuthaF'er]

Good eye Scottly! I need to give some thought to a bracket for mine since I can't use my stock airbox.

Use pods if you like but we are forewarning you. Many have used them before you but not likely without all the carb tweaking required.

Boys, as currently is, where should he start on the main (which sounds like the range he's having trouble with)?? Go up 2 sizes perhaps just for starters?

Hoping you also understand how to read the spark plug colors? That's important.   

[SohRon]

Also, by removing the airbox you're pressurizing your crankcase due to lack of crankcase scavenging (these bikes were designed to run with a slight vacuum in the case), which can affect the engine at high RPMs - among other really nasty things! Running the breather tube down below the engine to act as a road draft tube will help.

The best thing you could do, though, is lose the PODS and run the AIRBOX!

[scottly]

Good eye Scottly! I need to give some thought to a bracket for mine since I can't use my stock airbox.

Bailing wire will work in a pinch. Don't try to tune around air leaks, in any case..

[Stev-o]

Bunch of pods haters are we?!

Well, I was too, but my "Black Beauty" runs fantastic on the pods! Now I'm a believer.
She sure pops on decel though!!

[Jerry Rxman Griffin aka MuthaF'er]

Stev-O, I don't hate pods YET. I'll still have to tune mine in. Besides I'd bet all the pod haters would say that pods caused your header to rust! 

[Dave Voss]

Something to remember about the stock air box, is that besides housing the air filter element, it creates a still air mass for the engine to draw from, which promotes stable air flow through the carburetors.  Removing the stock air box and replacing it with pod air filters allows the turbulent air flow around the carburetors to affect the flow rate through them, and this causes issues under load and at faster road speeds.  Back when I tried using pod (UNI) filters, I ended up wrapping the sides of them so that only the ends were open, which helped improve flow quite a bit.  Also, remember that most pod filters need to be oiled, otherwise they flow way too freely, and don't trap dust as they should.  If you decide to keep the pods, be prepared to fiddle with the jets to get the air/fuel mixture dialed back to ideal.

[Stev-o]

Stev-O, I don't hate pods YET. I'll still have to tune mine in. Besides I'd bet all the pod haters would say that pods caused your header to rust! 

Ha, yeah, they would. But that's patina...

[sweet_baby_james]

I have a 1978 550k with PD46C carbs.  They have 104 mains, 42 pilots and a 4-1 MAC exhaust, runs pretty well, still needs a little tuning but is definitely in the ball park.

[Bankerdanny]

Pods vs no pods is a long running debate. I will say that based on the many threads on the subject it seems that the 750 doesn't have as many tuning issues with pods as the 500/550 does.

[jamesbekman]

Its just trial and error when jetting a carb for more airflow.  These bikes are not so unique to the world.  Tons of race bikes, race cars run no filters at all.  If you feel like messing with the jetting then go have a blast! 

[bollingball]

Its just trial and error when jetting a carb for more airflow.  These bikes are not so unique to the world.  Tons of race bikes, race cars run no filters at all.  If you feel like messing with the jetting then go have a blast!

And they are tuned to run wide open.