Topic: can someone suggest ideal carb jetting for cb550 with pods?

[dannyeven]

i have a 1977 cb550k with the Keihin PD X46A carbs.  stock jetting is #38 pilot, #90 main, and the E2349F jet needle on the 3rd groove.  can someone suggest a good setup with the pod filters?  there is an outside chance that these cabs are from the '77 CB500 because they had the E2350F slide needles in them when i got them.  i can't find an accurate model number for the 500 carbs anywhere. and, btw, whats the difference between the 2349 and the 2350, is it the taper?

i have the bike running pretty good but i have the pods taped over quite a bit to limit the air...obviously want to figure out the best way to not have the sweet duct tape on there. 

thanks for any suggestions.

[crazypj]

There is no 'ideal jetting'
 You may get some guidelines but it's all patience and testing to get it close as possible

[Kong]

I love a question that is unambiguous; can someone tell you how to jet for Pods?  Nope, no one can tell you how to do it.   The reason is that it is impossible to jet properly when pods are used. 

That may or may not be true, but it seems to be the general consensus from guys who have used pods and tried.  Any number of things could be the reason why engines with pods are so hard, if not impossible to tune, but some think its because there is no velocity stack built into them.  This leads to chaotic airflow at the carb intake and on downstream through the carb body.  Jetting can't compensate for chaos and so they never run well.

It would appear that the only way to get a 550 to run right is to provide some sort of velocity stack and then an airbox.  Some very ingenious ones have been put together.   In the end every discussion I've found about it - and there are a lot of them - comes to the conclusion that Pods don't work well and some guys who know what they are doing have been exasperated after trying combination after combination of jets, needles, needle heights, and adjustments. Its rumored that some have considered sacrificing first born male children to the appropriate god in hopes that might help.

A member, TinTop, here has made a small number of semi-custom airbox/filters for both 550s and 750s that incorporate velocity stacks as the supporting mechanism of the cleanable filter element.  Only a couple have been tried out so far so its hard to say if they are the solutioin, but they seem to be a step in the right direction.  I believe he still has parts to make one for another 550, and if not he may be considering a second production batch.  If you get one you will get the combined expertise of the dozen or so guys who already have a set of the things.  You can expect them to share tuning tips and such successes as they achieve.  I believe the guy who is making the things is planning on starting a tuning thread for them for just that purpose.

Oh, Those are the correct carbs for your bike.

[Flying J]

The ideal jetting for a carb with pods is to remove the pods and put on a stock air box. That is ideal.

[db22]

Has anyone ever tried using the original rubber intake boots, covered with filter material?  That should provide the factory intake contour, but without the troublesome airbox.  Then you could start trying out bigger main jets.  I'm going to dig mine out of the parts box and give it a try today.

Dannyeven, I have Emgo pods with 105 main jets and stock 38 idle jets in my PD46A (X46A) carbs.  Idle is perfect, but there is a "flat spot" at middle RPMs (this is a problem with stock induction as well, but worse with pods, on my bike).  The engine runs really hot with jets smaller than 105.  Timing can't be set properly, but that may be a separate issue.

I started using pods as a means of reducing the time and trouble in removing and refitting the carb rack during last winter's work.  Also, there are a few parts missing from my bike's original airbox assembly.  Several of the most knowledgeable people on this forum have a very low opinion of pods, and Tintop's stack/filter system is not cheap (though extremely cool-looking!).  I suppose I use them because my bike was an assemblage of odd parts when I got it, and I have no interest in restoring it to factory appearance.  The simplicity of pods appeals to me, too.  Time and experimentation will tell.  If you find that your engine runs hot, try bigger jets and change the oil often.  Otherwise, do as the wise ones say and put the stock airbox back in the bike!