Topic: Jetting size to use on 1972 Honda CB500 with Pod Air Filters and MAC 4-to-1?

[prestonvowels]

       What main jetting size have you used after installing pod air filters and 4 into 1 exhaust.  I have a MAC 4-into-1 on the way and I am planning to figure out the size of the main jets soon. I have read the technical articles on the website, but I haven't found any definitive content on what size people have used for re-jetting their carbs on CB500s. Anyone have this setup and found there main jet size to work really good?
       Also, where have you picked up your main jets or jet kit?

Update:
      No other mods to the engine, just plain stock. 1972 Honda CB500 Four K. Serial number: 2000001 series. Altitude sea level to 300 feet.

[DavePhipps]

I'm trying to help figure out those questions here
http://forums.sohc4.net/index.php?topic=78305.0
Nothing to answer your question yet though

You should also mention if it's an F or K model. It will help the more knowlegable ones here guide you

[bpcough]

I am in the same situation. Any answers yet?

[domer]

i cant tell you what you should use, but im running pods and a very open 4-1 on my 72 500. im probably gonna hear it for this, but its running 140 mains. yup friggin huge, thats how she came, she runs a little rich. as far as i know the rest of the motor is bone stock, but who knows. i have a few other carb related issues that i was supposed to take care of this winter, but we dont really have a winter in SF.... its tuff to tear your running bike apart when its 65 and sunny... but im going to drop the size a few notches as soon as i can

[odiewan]

My 73 CB750K is running 40 idle jets and 130 mains with a Carpy 4 into 1 and pods.
So 140 might be on the fat end (rich) but not by too much.

[domer]

ya i dont think its too far off, but its rich for sure... im gonna start picking brains when i finally get to tear em down, again. got a big friggin move coming up so its on the back burner for the moment

[RustyOlive]

kinda but not really in the same boat.. I have a 4-1 mac, and going to run velocity stacks from http://www.steeldragonperformance.com/products_2.html as soon as they arrive.. but still haven't figured out the jetting..

[Roach]

oh oh oh I'm gonna say it...

GO BACK TO THE STOCK BOX PODS SUCK

there is no way of knowing what actual jets to use its all trial and error. some people are able to get them running alright.. notice i didn't say perfect. other people just give up and go back to the air box because it is way more efficient then pods.

that all being said i run pods 120 jets on a 78 550k that doesnt mean that they will work for you and your setup they dont realy work for me they look nice but while i track down a stock airbox and rig up a bigger filter to it they will have to do

[TwoTired]

      What main jetting size have you used after installing pod air filters and 4 into 1 exhaust.

You ask for a main jet specification without providing specs for "pod air filters".  Anybody tabulate a list of different pod filter manufacturers?

Tell us how your filters change the carb throat pressure from stock at various RPM settings, if you want some sort of prediction on what correct main and jet needle parameters are appropriate.

The mac 4 into 1 was built to replace the stock mufflers, stock jetting is fine for it if the muffler isn't modified.

"Pod filters" is a style, not a specification.  IMO

[steam-powered man]

previous bike was a 78cb550k, ran perfectly and pulled very hard to 8K w/no end in sight.  too nervous about whipping this ole' bike to redline however, so it spent most of it's time between 4 -8K.  one plug a little sooty and others fine when tested at various "chops".  great bike, am looking to build another.  not identical to yours, but some conclusions may be inferred from this.  anyhow, my notes:

carbs - pd64a
emgo pods
oem 4/4 exhaust with baffles
mains - 105
slows - 42
clip position - 4th position down from the top
air screw - 2t out
needle - e23050f
relative compression - 150/155/160/150psi    
elevation 0-2000ft

full tune-up first, of course!
 
i found increasing the slows, leaving the mains alone, and fiddling with clip position beneficial

i left the battery box and side covers on, thus i had a little better airflow to the carbs.
i could create a little "pocket" of less disturbed air around the pods if i blocked the gap
between the outer pods and sidecovers with my legs.

some may say mods like these resulted in losing HP over stock.  no argument either way from
me, as i certainly don't have the time/resources to do "before" and "after" dyno runs on days
of identical temperature, humidity.  bike looked cool, ran great, #$%* it.    

[Drew70]

Hi RustyOlive,

I love the look of your bike. Doesn't look like you'll get much relief from your seat padding, or is that not required when your hanging off the side?

I'm keen to replace the stock steel rims on my '72 CB500K with some Aluminum Buchanan Sun Rims, but want to know how much wider I can go on the rear, before running into issues with chain clearance.

What are the dimensions of your rear rim? Also, What make and size rear tyre have you got on it?

My old girl is very much a work in progress, but she's come along way from the stock bitser I bought from my mate a year ago. Definitely a labour of love. I'm yet to fit the gold USD forks, triple clamps and twin discs I've recently acquired. If your beast is anything to go by, it will look killer & be a significant suspension and braking upgrade. (once I get all to fit).

Cheers Drew

[RustyOlive]

Thank you. But actually my seat is very comfortable. 1" memory foam is very forgiving. Did a 1000km road trip on the bike. No problems at all.

The rear wheel is a 18x5.50 chrome steel rim. Drilled and punch to the cb550 hub/lace pattern. Stainless spokes and nips finished it off. Wrapped with a 180/55/18 metzeller. Bike rides amazing with the cbr600rr forks. Dialed in to bikes weight, my weight and my riding style. Thats the awesome think about modern forks, you can tune them to your needs.

Any rear tire/wheel wider than a 130 needs offset sprokets. 160 tires will fit stock swingarms. But anything wider than that needs a bigger swingarm and more off set sprokets and minor machine work.

[JAG]

       What main jetting size have you used after installing pod air filters and 4 into 1 exhaust.

You ask for a main jet specification without providing specs for "pod air filters".  Anybody tabulate a list of different pod filter manufacturers?

Tell us how your filters change the carb throat pressure from stock at various RPM settings, if you want some sort of prediction on what correct main and jet needle parameters are appropriate.

The mac 4 into 1 was built to replace the stock mufflers, stock jetting is fine for it if the muffler isn't modified.

"Pod filters" is a style, not a specification.  IMO

What TT said. It's not east to get the correct adjustment with pod filters. Especially a cheaper version, if they are emgo, with the paper filament/filter. That being said, I would make sure you are not caught in a storm and get those wet, it could spell disaster..

I digress..

Richer is better, but too rich or too lean could cause your engine issues.. If you have stock jets in there, I would slowly move up to bigger diameter/orifice, until you reach a point that is comfortable.

[Bankerdanny]

Those jet questions are 5 years old at this point. This thread came back from the dead because someone complimented RO's bike.