TOPIC:

This winter I have learned more about motorcycles and mechanics than I ever thought I could but here I am almost done and need some more direct guidance.
When I bought this bike not running, tired, and plain ugly the air box had already been tossed so I bought some new smaller pods to actually fit the carbs without pushing each other. Well the rebuild kit I got for the carbs had all stock as we all know is the only way to buy them, and adjustable needles with the same profile as the stick needle. Well after making the choke flaps and drilling out the mains with I believe a #61 bit (I'll have to check when I get home) but it was two sizes over stock the bike would start and idle well but when riding there was a very obvious flat spot mid range, so I raised the needles from stock one clip which as far as I can tell as a new rider took care of the flat spot. Finally the question is while I'm waiting for gauges to properly sync my bench synced carbs I read to turn the air screws from seated lightly to the highest rpm then lower the idle knob back to appropriate idle. I did this but all of the screws are no more than a quarter turn out. Should I drill the mains another size larger? Will that effect my needle setting? Also aftermarket petcock seems to cut out around 5500rpm so after a long stretch of highway it bogs out with lack of fuel. This site has gotten me so far with past posts but the final stretch is in site and I need help.

Sorry for the long first post but I also wanted to mention I have stock exhaust. The only just pods and deleted all of the exhaust bs and capped all of the vacuum ports

Sorry for the long first post but I also wanted to mention I have stock exhaust. The only just pods and deleted all of the exhaust bs and capped all of the vacuum ports

It would help others if you put your exact bike year, model etc., in your signature.

From the description it must be a Kz550A, Kz550C, or Kz550D.

The proper way to set the screws is to turn them in slightly (richens) until the RPMs just start to drop, then turn them out slowly for maximum RPM, then turn them out more (leans) until it drops again, then turn them back in until you just get back to the max RPM. That is called the lean-drop method. You want to adjust from the lean side, because if you adjust from the rich side, gas can accumulate in the intake and give you a false setting.The bike's stock tach is not precise enough to do this accurately. It takes an external, electronic tach to really see the tiny changes in RPM.

This is usually the last step after syncing etc. The bike should be fully warm.

1/4 turn is probably too few, but that may change if you use the above method.

If it idles best at 1/2 turn out to 3/4 turn out on the air screws, then your pilot jets may be too small, as is usually the case when converting to pods. If it starts and runs ok, there is no pressing reason to drill the pilots just so you can turn airscrews out more. But usually it means there will be some lean areas during cold temperature riding.

But make sure there are no vacuum leaks before deciding to adjust anything, since vac leaks will greatly affect the air-screw setting.

You can try to drill the pilots to 34. That requires drill #80. That's the tiniest bit in the typical set, so it takes some patience. The drill should be very slow, somewhere around 60 to 100 RPM, and don't force it.

Thank you, I did have a couple air leaks after the carbs but have fixed them. I won't drill again untill I get them synced and see how it effects things.

I spent a lot of time in my youth tuning the TK22 Carburetor, and with pods I was running the stock pilot jet, a #105 main jet, and the needles in the middle position.

With that setup it almost ran as good as with the stock airbox.

Happy tuning !

Thank you! It seams like I'm on the right track then! Just finished my seat and can't wait for more consistent warm weather to ride and tune

Well went ahead and used some glass jars and tubing to make a manometer that sealed pretty well and got to balancing the carbs. i have to say the bike still need fine tuning (better setup or just buying a manometer) but it idles so much smoother!
main question is for adjusting the air screws where should the idle be?
i have had the idle at about 1200 because it seems smoother than lower rpms which makes me think the mixture may be a little rich? i have the screws all the way shut because with 5/8 open or more it bogs and i don't have enough turns closed to make it bog the other way.
my understanding is that opening the screws makes a leaner mixture and closing gives less air for a richer mixture.
so if my understanding is correct i need to remove the pilots and get my #80 bit out?
any help is greatly appreciated! with the "sync" the bike pulls great through all rpm's just an occasional slight hesitation from idle

That is the only way I've been able to properly richen the lean spot off-idle. I check it with a wideband o2 sensor. I usually go to 37 on the pilot (#79 drill bit) when using Emgo Pods, but you should drill in steps, because there is no going back once you drill. If you have a set of rebuild kits, then you should have at least two sets of pilots, no? (New ones and old ones? Drill the old ones first.

I also use a tiny tiny dab of anti-seize on the jet threads to make it easier to take out later.

You can also try to use a larger main and play with the needle to mask the problem. But that is really just richening up other areas more than you want to. It will still run ok, but cruising will use more gas than necessary, and acceleration performance may suffer on hot days.

Well low and behold the pilots that were in the bike when I picked it up we're drilled with #79 bit. Surprised me because the main was stock. Anyway I cleaned them up real good and I'll decide tonight wether to remove the carbs to swap them out or try switching with the carbs in place. Thanks!

Yes, unfortunately, when you remove the carbs, you often have to re-sync. That's why I've developed those tools for removing the bowls and replacing jets while the carbs are still on the bike when using the stock airbox. It's easier, but may take longer for the actual jet swapping.

But with pods, it may actually be a wash, time-wise, because it takes much longer to swap the jets, especially the pilots, if you don't remove the carbs. It depends how fast you can re-sync.

Well im getting good at pulling the carbs, the pilots that were drilled out with the #79 were too lean as i was almost all the way turned out to get a reaction from the motor so i drilled the stock ones from the kit with #80 and found a much more realistic setting. unfortunately i definitely need to rebalanced the carbs!
i have had a real hart time forking out the cash for a manometer and even built a trial bottle style homemade one which got me real close the first time but i don't feel great about the air tight seal on each lid so i think ill have to either buy better fittings and take the time to build it right or stop messing around and buy a set.
i guess ill need them a by brother picked up an 81 yamaha xj 650 and rode it a week before (something went wrong)
well being the nice brother i am i tore it down and split the case and he managed to shatter the primary chain!
oh well the garage was looking way too tidy with my bike all put together.
been too cold to test throttle response with this new primary jet but i really need to balance first anyway to get rid of the sloppy sound.