maybe this means something

so after my coil mod, i can better define what i assume is a carb issue. since i've had the bike it runs best in the prime position on the petcock. well after the mod i tried runnin it in the run postition. either way, it idles a little rough. but in run, at cruisin throttle she drops a cylinder or two at random (3000-6000 and not pullin a hill or anything). but if i get on the throttle hard/quick, she's not tryin to rip me off the seat, but smooth at least. i switched it back to prime and, while slightly rough, she handles cruising throttle much better. but if i get on the throttle hard/quick, she hesitates real bad for one or two seconds. i assume that means a carb cleaning and adjust is at least in order, but if anyone sees something specific i should look for, i'd appreciate the advice.

My first thought would be to clean and examine the petcock and stand pipes (the petcock "filter tubes" that insert into the tank), since that's what seems to be making the difference in how it's running.

see, i didn't even know there was a filter there. that's why i ask the dumb questions.

ok, that didn't work. pulled filter, it was clean. replaced whole petcock with one off my other bike anyway. i'm wondering if the petcock is the problem still. i disassembled both and the o rings and diaphrams looked good but with the bike running i couldn't feel any suction against my finger. should i? the hose is coming out of the second carb and there is another line coming out just forward of it on the same carb and it's always had a lot of suction and if i plug it, the bike idles up and seems to run smoother. i plugged it and rode a few miles once and on the highway that it didn't seem to make much difference. so there's the newest pieces to the puzzle for what it's worth.

r1ng3l78 wrote:

...at cruisin throttle she drops a cylinder or two at random (3000-6000 and not pullin a hill or anything)...

Drops a cylinder? Could it be a coil problem? Or fuel starvation at the gas cap? Or bad float settings? How do your plugs look?

Hmmmm. I wonder if you have the petcock connected to a carb vent line and the carb vacuum line open ?
I'm not familiar with your carbs but I think you will find pictures on wiredgeorges website which show the hose connections on some carbs. If you have a vacuum line open / not capped the bike will run like crap. Usually the vacuum line is connected to the petcock.

ok vaccum line was off. hooked it up, didn't notice a big difference. it's now idling a little smoother but if i give it more than half throttle or more, the hestitation and stumbles still there. i revved it in the driveway and with no load, it does when i quickly hit the throttle. but i removed the air filter (a K&N barrel/stock type and it's clean) and she was smooth. screwed the cap back on (no filter) and closed the seat, slightly less smooth. ran it down the street with no filter and didn't seem any better at all other than when it quite stumbling, it had a lot more power. i have a factory service manual and double checked that the plugs were the right kind and the gap was correct. they have about a thousand miles one them and these results are after i put them through the plug cleaner and regapped. here's what they looked like when i pulled them (cheap camera, but you can get the idea).

and another

I would say that you are losing either #3 or #4 now and then as the plugs in two cylinders are pretty black.. I would start with a fresh set of plugs, and a good carb cleaning, set float hieghts and then see what it does....

1045

Hey Tennessee! Have you tuned this bike up? Adjusted the valves or checked compression? The 3/4 cylinders look like there is a combustion problem. Also, you swapped out the stock airbox? How about stock pipes? What jetting in the carbs now?

since i've owned it (bout 3 months), i've mostly chased down wiring gremlims and changed the plugs and oil. valve adjustment was on the list but i'm planning on running a compression test this week. it has the stock airbox with a K/N in it and a kerker style (can't find a name on it) pipe. it didn't have a baffle when i got it but i did rob one out of a parts bike and put it in with no fiberglass. i have no clue about the jetting yet. i put some seafoam in the tank the other day and it did make a noticable but not dramatic difference so i'm probably lookin at a carb adjustment/sync if not a rebuild.

I suggest you may want to perform normal tune up steps in the order suggested in a factory service manual or Clymers before messing around with the carburetors anymore. If the valves have no clearance, or you have a compression issue, no amount of carb tuning will make the plugs look any better I think.