Topic: So, you want to run pods?

[Bigmant]

I will leave this here in case someone needs it, but here is my pod tuning journey. Hope it helps someone:

http://forums.sohc4.net/index.php/topic,190368.msg2215989.html#msg2215989

But to save the reading, here is what worked for me.

The new setup is as follows:
#140 mains
Needle jet at the lowest setting (most rich)(5 from the top)
Air mixture screw half turn
4-1 Carpy’s Yoshimura style exhaust
4into1.com pod filters

[TwoTired]

I will leave this here in case someone needs it, but here is my pod tuning journey. Hope it helps someone:

http://forums.sohc4.net/index.php/topic,190368.msg2215989.html#msg2215989

But to save the reading, here is what worked for me.

The new setup is as follows:
#140 mains
Needle jet at the lowest setting (most rich)(5 from the top)
Air mixture screw half turn
4-1 Carpy’s Yoshimura style exhaust
4into1.com pod filters

How do you know it “Worked”?  Dyno tests?  Quarter mile times?   Or, “It runs and drives”!  How does it compare to the stock configuration besides looking different?

[Mark K]

I'm at the point in my 'build' about to reinstall the Keihin carb bank onto the engine. Just replaced the carb rebuild kit's brass pieces with the brass that was in the carbs when I got the bike, which wasn't running at the time.

1973 CB750 .50 over stock pistons (recommended by the guy who did the boring of a used stock cylinder). Had to replace the cylinder and head, a PO had installed a big bore kit and pods, but engine was seized when I bought bike and couldn't reuse the pistons and couldn't find new rings, but I am getting off track here.

Bike didn't have a stock air box, I figured I'd just throw some pods on but after reading this extended forum, I have been 'schooled' as to my foolishness.

I am going to install a 4-1 Delkevic exhaust (already purchased) as restoring back to original exhaust and other bike parts is way above my financial means, so I'm taking the cafe racer route. Bike had a rusted out, 4-1 exhaust when I bought it, went to the junkman.

The Keihin carbs (657A) have a 130 main jet and I believe the other jet (slow?) is a 40.

My question is -
will the main jet (130) work okay with .50 over cylinders and 4-1 exhaust and probably a stock air box, if I can find one?

Thanks,
Mark

[seanbarney41]

I bet it will be a good safe baseline, but it's gonna be too big.  I guess 110-120 main for that combo. 

[Mark K]

Thanks for your advice, I'm removing the 130 jet right now and installing the 110 that came w/the rebuild kit for now.

[dave500]

pods or similar on proper race engines yeah,if you want a fully tractable easy ridable in traffic bike with good off the line pull and power use the stock air box system full stop,you truely wont beat the stock induction system.

[Mark K]

pods or similar on proper race engines yeah,if you want a fully tractable easy ridable in traffic bike with good off the line pull and power use the stock air box system full stop,you truely wont beat the stock induction system.

Stock airbox installed (Steve-o was kind enough to sell to me) top half right now, cleaned the filter and need to oil and install with the bottom half.

[RAFster122s]

Oil? What filter element is in your airbox?

[Mark K]

Oil? What filter element is in your airbox?

K & N, on the filter says it can be oiled. Does anyone oil these filters??

[newday777]

Oil? What filter element is in your airbox?

K & N, on the filter says it can be oiled. Does anyone oil these filters??

Yes, K&N are to be oiled after cleaning them. The oil is what catches the dirt particles.

[Mark K]

That's what I thought, I've used K&N oiled air filters in other vehicles.

[Wingman2003]

so happy to find this thread. once again, what a great community. Gotta make a donation!!
I love the look of velocity stacks, but wondered... Can't wait to read thru all this info!

[Sunset Fab]

OK here is the story. I am building a street tracker/scrambler. Stock air box is not an option.. What do all of you recommend for the next best set up
Needs to look cool and work
Thanks, Steve

[seanbarney41]

Run some after market carbs that have a wide enough range of jetting options to make your combination work

[newday777]

OK here is the story. I am building a street tracker/scrambler. Stock air box is not an option.. What do all of you recommend for the next best set up
Needs to look cool and work
Thanks, Steve

Welcome aboard the forum. What bike do you have??? You can't get good answer without that for any problems you might ask about. Include that when ever you ask a question please so you don't have to be asked.

Did you read through each reply in this thread before posting this reply? Lots of information you missed if not.

Honda designed the air intake for the best performance. The stock air box to carb rubbers have a venturi shape as part of that performance. Coolness is lacking heavily in this instance.
Most pods do not have that venturi shape needed to compress the air flow faster so it mixes properly with the atomized gas.

Go to the new members introduction section and introduce yourself and your bike.

[Sunset Fab]

OK here is the story. I am building a street tracker/scrambler. Stock air box is not an option.. What do all of you recommend for the next best set up
Needs to look cool and work
Thanks, Steve

Welcome aboard the forum. What bike do you have??? You can't get good answer without that for any problems you might ask about. Include that when ever you ask a question please so you don't have to be asked.

Did you read through each reply in this thread before posting this reply? Lots of information you missed if not.
 


Honda designed the air intake for the best performance. The stock air box to carb rubbers have a venturi shape as part of that performance. Coolness is lacking heavily in this instance.
Most pods do not have that venturi shape needed to compress the air flow faster so it mixes properly with the atomized gas.

Go to the new members introduction section and introduce yourself and your bike.

1980 CB650   So what if I incorporate the stock rubber mounts into a custom air box/filter assy?

[newday777]

OK here is the story. I am building a street tracker/scrambler. Stock air box is not an option.. What do all of you recommend for the next best set up
Needs to look cool and work
Thanks, Steve

Welcome aboard the forum. What bike do you have??? You can't get good answer without that for any problems you might ask about. Include that when ever you ask a question please so you don't have to be asked.

Did you read through each reply in this thread before posting this reply? Lots of information you missed if not.
 


Honda designed the air intake for the best performance. The stock air box to carb rubbers have a venturi shape as part of that performance. Coolness is lacking heavily in this instance.
Most pods do not have that venturi shape needed to compress the air flow faster so it mixes properly with the atomized gas.

Go to the new members introduction section and introduce yourself and your bike.

1980 CB650   So what if I incorporate the stock rubber mounts into a custom air box/filter assy?

I dunno. Never have tried to make a custom air filter so most likely you'll be on virgin ground and will have to do lots of plug chops to get it running without problems.

[Sunset Fab]

Stu, if the factory boots have a built in taper why won't velocity stacks work?

[RAFster122s]

Study the engineering on using velocity stacks and the space needed on them and you will find the limitations for the space and the need for unobstructed air flow. Velocity stacks are designed for optimizing air flow at high rpms of racing. Not that they don't have benefits at other speeds. Stock motors typically don't need them or see much from them...

[newday777]

Stu, if the factory boots have a built in taper why won't velocity stacks work?

Did I say velocity stacks won't work?

[Stev-o]

Stock air box is not an option.. What do all of you recommend for the next best set up

"Breadbox" on my 750 K3...



https://www.ebay.com/itm/165887404171?hash=item269fa8e88b:g:F2IAAOSwQdhgeJ2J&amdata=enc%3AAQAIAAAA0OIXvKv3PvrD6kLp7vihI1lMhtZ8wF%2B6Pjt2sExK44GcwNLbq24pWMCIJAYclqeywsCjrTJfCfGtCx%2FpkZHIZJ7vw%2BWocgnQpzwwmqWbxb5WMjCEyz7EWAVYdmWcR7Unf0KchRJOeyDANC1WTs%2F1bgzwvth8uWqVQ%2F1F0uJrXsBf4EUyFI8wqV8M0LmXc0yaic%2B6h9xqCGTbfpZL2LHQzBCwK4cm1G2FWxMNr8FS5lr9irw4PdYrOV%2B0olOENc9sv00Ldw3ozmaorbSeJbZYJqc%3D%7Ctkp%3ABk9SR7yOnpGJYg

[Sunset Fab]

Stock air box is not an option.. What do all of you recommend for the next best set up

"Breadbox" on my 750 K3...



https://www.ebay.com/itm/165887404171?hash=item269fa8e88b:g:F2IAAOSwQdhgeJ2J&amdata=enc%3AAQAIAAAA0OIXvKv3PvrD6kLp7vihI1lMhtZ8wF%2B6Pjt2sExK44GcwNLbq24pWMCIJAYclqeywsCjrTJfCfGtCx%2FpkZHIZJ7vw%2BWocgnQpzwwmqWbxb5WMjCEyz7EWAVYdmWcR7Unf0KchRJOeyDANC1WTs%2F1bgzwvth8uWqVQ%2F1F0uJrXsBf4EUyFI8wqV8M0LmXc0yaic%2B6h9xqCGTbfpZL2LHQzBCwK4cm1G2FWxMNr8FS5lr9irw4PdYrOV%2B0olOENc9sv00Ldw3ozmaorbSeJbZYJqc%3D%7Ctkp%3ABk9SR7yOnpGJYg

So how does it work?  any tuning problems?

[Stev-o]

Stock air box is not an option.. What do all of you recommend for the next best set up

"Breadbox" on my 750 K3...



https://www.ebay.com/itm/165887404171?hash=item269fa8e88b:g:F2IAAOSwQdhgeJ2J&amdata=enc%3AAQAIAAAA0OIXvKv3PvrD6kLp7vihI1lMhtZ8wF%2B6Pjt2sExK44GcwNLbq24pWMCIJAYclqeywsCjrTJfCfGtCx%2FpkZHIZJ7vw%2BWocgnQpzwwmqWbxb5WMjCEyz7EWAVYdmWcR7Unf0KchRJOeyDANC1WTs%2F1bgzwvth8uWqVQ%2F1F0uJrXsBf4EUyFI8wqV8M0LmXc0yaic%2B6h9xqCGTbfpZL2LHQzBCwK4cm1G2FWxMNr8FS5lr9irw4PdYrOV%2B0olOENc9sv00Ldw3ozmaorbSeJbZYJqc%3D%7Ctkp%3ABk9SR7yOnpGJYg

So how does it work?  any tuning problems?

Works great, once the proper size jets were determined/installed, has not been an issue to keep tuned.

[seanbarney41]

Stock air box is not an option.. What do all of you recommend for the next best set up

"Breadbox" on my 750 K3...



https://www.ebay.com/itm/165887404171?hash=item269fa8e88b:g:F2IAAOSwQdhgeJ2J&amdata=enc%3AAQAIAAAA0OIXvKv3PvrD6kLp7vihI1lMhtZ8wF%2B6Pjt2sExK44GcwNLbq24pWMCIJAYclqeywsCjrTJfCfGtCx%2FpkZHIZJ7vw%2BWocgnQpzwwmqWbxb5WMjCEyz7EWAVYdmWcR7Unf0KchRJOeyDANC1WTs%2F1bgzwvth8uWqVQ%2F1F0uJrXsBf4EUyFI8wqV8M0LmXc0yaic%2B6h9xqCGTbfpZL2LHQzBCwK4cm1G2FWxMNr8FS5lr9irw4PdYrOV%2B0olOENc9sv00Ldw3ozmaorbSeJbZYJqc%3D%7Ctkp%3ABk9SR7yOnpGJYg

So how does it work?  any tuning problems?

Works great, once the proper size jets were determined/installed, has not been an issue to keep tuned.

I also have experimented with the old school bread boxes.  They work pretty good.  The key is that they use an intake boot that is similar to the oem boots, which actually are a velocity stack.  Some of the old bread boxes (there were at least a few different manufacturers) can even accept, or easily be made to accept oem intake boots.  At some point, however, through all this experimentation, it became obvious that the bike just performs better with the stock airbox.

[TwoTired]

When these bikes were first sold, they had what was considered high rpm engines.  This requires smooth airflow through the carb throats.  Honda made an induction system that would flow smoothly drawing in air, filtering it, and than provided space for turbulence caused by the filter to settle.  The v stack shaped carb inlet drew air from that quiet area and directed it into the carb throats.  This allowed predictable flow over a wide RPM range over the fuel exit points of the carb.   Pods or the breadbox place all the filtered but turbulent air right at the mouth of the carb (or v stack).  There is no doubt that the turbulence effects fuel delivery at unpredictable air speeds.  I have yet to see qualitative data, like from a dyno, to show the difference over the entire operating range of the motor between the stock air box set up and PODS or a bread box.  I just can’t accept an anecdotal opinion of “runs good” as an adequate endorsement, without some sort of measurement data to support it.  Honda spent a lot of money in the stock design.  Does it really make any kind of sense that tossing it for a $15 replacement barely engineered , will in any way actually improve the engine power?