Selecting the right pilot jets

Well, I think I've figured out why it was backfiring out of carb #1. My dad noticed that a cap I had on the vacuum port had rotted off, letting too much air in the engine and leaning it out on that cylinder. I forget if this vacuum port was part of emissions I had blocked off, or if they are just supposed to be capped. Theres just two ports, one on cylinder #1 and #4.

Something else that bugs me is that I can't get the engine to rev up with a quick shot of the throttle. When idling, you can quickly rev the throttle halfway and hold it and the engine will die. Sometimes it just hesitates for a second and then revs up. If you manually pump the accelerator pump a few times and then rev it up, it revs fine. I also took some temperature readings off each exhaust port. The #2 cylinder was only about 100*, whereas the other 3 were 160*-170*. The #2 cylinder carb has the accelerator pump on it, so I wonder if something is causing problems there.

For reference if applicable.

I think that is a different setup than what I have. Mine does not have a vacuum petcock, and it has two inlet fuel lines. Also, the vacuum ports I blocked off are actually on the intake boot that attaches to the cylinder. Thanks though!

I wish these bikes had only one carb, how much better would that be?

I took the bike out for a spin today after replacing the vacuum plug that had rotted away, and I think it runs worse than it did before the new jets. Once I was on the road, it was embarrassing how terrible it ran. It sounded extremely lean, even when I fully applied the choke. This used to happen, just not nearly as bad, and applying the choke would clear it up. I have no idea why the choke didn't help in this case. Once I got home and the bike had warmed up, it ran better, but I was frustrated with these carbs, so here is what happened:



Two of the carbs are missing in the picture, as one was being stripped of paint and another soaking in carb cleaner. Somebody had spray painted both the carbs and engine with black paint during sometime of the bikes life, and half of it has flaked off. I thought I would do the carbs a favor and at least strip the nasty black paint off. Upon disassembling, I noticed that the new accelerator pump diaphram I installed about a year and a half ago is already cracking. I've always made sure that the gas in this bike was fresh or had stabilizer in it to prevent this kind of stuff from happening. I'm pretty sure I bought the rebuild kit off of ebay, because the dealer price was outrageous. Z1enterprises wants $30 for the whole kit, and are out of stock. I don't know what to do about it, but I'm not too happy that this thing has cracked. The lever for the accelerator pump has had some gas on it lately, so I'm assuming this diaphram is definitely leaking.



Something else I noticed was that the caps on vacuum ports #2 and #3 cylinder boots are a little loose. I'm going to find a tighter fitting cap to make sure that none of these ports are leaking.

Here is a comparison of one carb I stripped and another which still has the terrible paintjob.




Does anyone have some suggestions on the accelerator pump? I've heard of people getting rid of it altogether, but I'm not sure how you make up for the gas it provided.