rough running, missing.... need help

[grabberblue]

My bike is running like crap right now, good under heavy acceleration and OK when cold but after warmed up and regular running it is terrible.

Originally I took off carbs to clean and change out diaphrams with pin holes.
I noticed 110 main jets were installed, I have pod filters and modifyed exhaust. My search noticed that 120 jets were stock for 80 G so I went to get new jets. I got 125's for 1 & 4 and 127.5's for 2 & 3. I installed them yesturday and acceleration was better but the problem I was hoping to solve with the new diaphrams and bigger jets got worse.
When I removed and changed the plugs with the 110's they were black and sooty, but I did have sticky needle flooding a couple of the carbs a while ago. I have not yet checked the sync, but the bike was running good before all the changes.
My first change was the pod filters, bike ran good, then the stuck valve on #4. This is when I opened the carbs to fix and clean and noticed pin holes in 3 of the 4 diaphrams.
Second change was to replace the damaged exhaust, I bought small mufflers that were very loud, so I plugged them up a bit. Might I be choking the engine? the bike developed a little backfiring guring deceleration.
3rd change installed new diaphrams, bike ran a little better but did not fix poor running.
4th change jets, problem slightly worse, except acceleration much better.
Any ideas?
Thanks,
John
TIA
John

[pggg]

Maybe check the slides for smoothness - sticky slide that stays open after full throttle makes the motor run like crap.

[randy]

Grabberblue, have you done a compression test? Good place to start to identify troubles.

[grabberblue]

Thanks,

I will check slides tonight
I will test compression tonight also

[Ken Talbot]

Sounds like you may have installed K&L jets that are numbered in some entirely different way. I've lost count of how many people have bought after-market jets with a number that looks just a bit bigger than the Mikunis were stamped with, only to find that the actual bore in the jets is way too big. Have a look at the K&L Curse thread

[RUSH]

I might suggest that you change/ replace only one thing at a time, rather than a bunch. That way you wont run into the problem of one thing helping and the other making the problem worse. IE dont raise the clips on the needle jets and change your float level at the same time. Go about it slowly and methodically.

see some posts about those pod filters blocking airflow!

[grabberblue]

Update

Thanks all,
Ken I only changed the Main jets (4 pcs total), did not install K & L kit.
Heres what I found when I was riding home last Friday after posting.
My petcocks were not functioning when I bought the bike so PO had hosed the petcocks to work only in the PRI position. While
I was riding I shut the petcock off, after about a block the bike started running fine, untill gas got low in bowl.
This made me think that the bowls of the carbs are getting too full, so I yanked the carbs and reset the float height. My Clymer manual says .906" + / - .020" for a '80G which I set last time when I pulled them so this time I went a bit lower to see what kind of difference it would make. I adjusted them to about .890" about .016" lower than before. My ride into work this morning showed no noticeable improvement, maybe a slight one. So I did the "shut it off, turn it on" thing for the rest of the ride which it rode fine.
Questions I now have are: can I lower the height more?(wether I can or not I'm goinmg to try!)
Is my book right? ( it says to measure from gasket surface to top of float. The shut off needle has a spring loaded pin, I measured it as it is, without compressing this pin which will hold up the floats.
Is this the right way?
TIA to anyone who has any comments.

[Ken Talbot]

Remember that when you 'lower' the floats with the carbs upside down on th workbench, this actually raises them in the float bowl when they are in operation. Higher floats in the bowl equals a richer running condition. Maybe you want to go back the other way a bit....

[pggg]

Fuel(faulty)taps.

[grabberblue]

Thanks Ken, you are right, I went the wrong way. I will take it appart again this evening and try again.