Jetting when putting Pod air filters on

I've done some searching on this site about jetting when running air filter pods but the one suggestion has a person running the bike testing it, then re-jetting running the bike until a person finds the right fit. Rather than the trial and error method, is there a chart out there that tells a person what jets they should have based on air filters and elevation? Do the air pods create that much more air to require re-jetting? How much does modified exhaust systems play into jetting?
Thanks for any and all input.

 

no it is a total trial and error thing. what you are trying to do is put the flat spot in the throttle at a point in the power band you can live with.
run a plug chop rejet plug chop rejet it could also be you need to shim the slide needlse
here is a link on tuning your carbs
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

a litttle theroy
http://www.iwt.com.au/mikunicarb.htm


this link has a slide card
http://www.dansmc.com/carbs2.htm

 

exhaust is not that much of an issue stock exhaust is pretty free flowing .

the pods eliminate the velocity stack effect that the carb boots give the air flow, you could mount the pods to stacks and improve the situation.

 

From looking at the title, this bike came from CA or sea level, it now lives at 5,500 ft elevation. What are the odds that once I put the pods on, that it is jetted correctly?

 

Exactly zero, regardless of where the bike is from.

 

what bike do you have please post it in your signiture line or at the beginig of each thread

The house always wins
if you are not willing to do the work do not try to convert to pods just that plain and simple.
your bike will run it will look cool but will never run like it should you will have a flat spot in the power band where that spot happens will be dictated by you with carb tunning. YOUR PODS ARE NOT GOING TO MAKE THE BIKE FASTER OR QUICKER.
pods are just eye candy

read this link it will tell you some about pods
The Information Overload Hour

 

Whats the reason for putting pods on? A lot of work went into designing the factory airbox to give it consistent performance across the RPM range. Any increase in performance in one area is usually at the cost of another. CV carbs are very picky because they require vacuum to lift the slides, modifying the intake will result in a change affecting when and how they lift. You also loose the velocity stack when removing the intake boots resulting in "choppy" airflow. Most success stories are on non vacuum slide carbs with dyno and chop tuning. If you have the airbox, the consensus is stick with it.

I have a good article from a Mikuni engineer explaining these mods.

 

Here' s the correct procedure for what do with jets/pods/etc...

1. Remove the pods, put the original jets, airbox, filter, needles, and boots back on. Put your mixture screws back to factory initial settings, re-colortune, and re-balance.

2. Now, go ride without the hassles of the pods

 

Thanks so much for the replies.
The bike I have is a 1980 XJ650. I bought it as a non-runner. Because of the condition of the bike, my plan is to make it into a brat bike. The only reason I had planned to put the pods on, was to clean it up. I'm not looking for more power etc, I just like the clean, stripped down look. Is there another option other than the stock air box and pods?

 

Nope.

Stock airbox, boots, jets, needles= best performance

Pods= all the headaches you want, reduced performance even though you think it's more because its louder, etc....

 

There is another option. Spend a few hundered dollars on a set of cable operated carbs, and a few more hundred on jets and dyno runs to get it dialed-in.

Trust me on this: when you're riding you can't see the pods, or the airbox/sidecovers. Are you building a bike to win shows, ore are you building a bike to ride?

 

Tru dat

 

You've convinced me that stock is the way to go. I went out t0 check out the stock airbox (I've had this bike for 4 days now) and the original box has some cracks in it and it doesn't even have an air cleaner. I guess my next step is to see if I can repair the air box or find a new one, or take on the head aches of the pods. As a little more clarification, I debated for the first 3 days or so, if I wanted to try to bring this bike back to life or part it out (its in that bad of shape) The motor did turn over but I'm still not sure if it's going to require a motor rebuild. I need to figure these things out before the air filter issues but I also what to try to plan ahead. Thanks for everyones input.

 

Did you do a compression test?

That will tell you a lot about the engine right away-----

 

I wanted to do a compression test this weekend. Do you know what compression readings are normal?
Thanks,

 

650, 750 air-cooled engines:
Minimum: 128 psi
Standard: 156 psi
Maximum: 171 psi
Max. variance between lowest and highest: 14 psi

this link will tell you how
http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

 

I just looked at the bike and the air cleaner housing. The part where the air cleaner should be is missing the top and it has some cracks and pieces missing. If the compression check is good, I will either need to get a new housing or deal with the headaches of pods or I'm wondering about a third option. The part that attaches to the carbs is in good shape. Could I find a single air cleaner that would attach over the approx 3X4 opening that leads to where the air cleaner should be. Or in other words, I could cut the box that housed the air cleaner off, and make an attachment for a single air cleaner that would sit where the box use to sit? Would that work and would I avoid the problems pods present?

 

You could, but you will probably still have headaches. The CV carb system is very sensitive to changes or lack of maintenance. A good example is my 750 Kaw, I chased a part throttle lean condition for months. Turned out the cheapy air filter I "saved money" on was to blame.

 

Can you rebuild the air box? Sometimes duct tape, epoxy and sheets of plastic can do wonders! Never tried it on an airbox though.

 

So I have good news and bad news.
The PO cut the wires behind the head light because he didn't have a key and was trying to figure out how to hot wire it. I got that figured out and the motor cranked over great (thats the good news) The bad news is I did a compression check and starting with the far left cyl. my readings were 75, 210, 200 and far right was 90. When I first got the bike, since it has been siting for close to 20 years, I put some ATF down each cyl. I cleaned that out the best I could by cranking the motor, then took the readings. On another bike I rebuilt I used half ATF and half acetone, so I might want to do this again with some acetone. Anyway, do I have a parts bike on my hands? Would the ATF/Acetone help? Is there a reason the outside cyl. readings are so much lower? Could it be a valve clearance issue? Thanks for any input.

 

check your valve clearences.
atf acetone will help free stuck pistons
did you add some oil into cylinders for a second test?

are you sure your tester is good
it could be the tester or the tester
from information overload

h) If the readings are below spec, then shoot about a teaspoon amount of motor oil into each cylinder, crank the engine over a few revolutions with the starter (to spread the oil around), and then re-test each cylinder using the above procedure.

thats filter out airbox open throttle fully open all plugs out tci disconnected


not a parts bike yet

 

And the plot thickens.
I let the outside cylinders soak with half ATF and acetone for a few days. I cranked the bike over to get the fluids out, checked compression and they were still low (60-90). I then put a little Engine Restore and Lubricant in those cylinders, let it sit, then cranked it over slow to spread the oil, let it sit some more then did another compression check. Far left came in at about 200 and the far right 220.
Is this a bandaid on a severed arm, or is there a chance this could work???

 

It depends, Don't make any decisions until you can run the engine and get it to operating temp. It is common for a engine that has been sitting for a long time to have low compression . Surface rust on rings and valve seats causes this. If it was my project I would clean the carbs and get the bike to run for 15 minutes or so. Let it cool and check the numbers, I bet they will improve.
I have put thousands of miles on bikes with lower than spec compression numbers

 

It's a bandaid, but it looks like the rings aren't stuck anymore. That engine-restore crap is just snake-oil in a can. I would flush it out, and retest with engine oil only. Then you can determine if she's a runner or not. As long as the compression is high enough for those cylinders to fire you can run it until it won't run anymore

 

I turned my motor over to a shop to have head gaskets replaced and we looked at the piston rings on my bike and there was blow by on all cylinders and a head leak not too expensive and I hope to have it back up and running soon the weather is getting nice when it's not snowing.