TOPIC:

Yep, try it.
Steve

650mod wrote: All 4 plugs are fresh and it still did it. So if what you're saying is maybe the culprit with the wore- I could switch the leads from cyl 2/3 to see if it follows to cyl 3. What do you think?

Since it's the #2 cylinder I would test the vacuum line from the petcock (I assume you're using a vacuum operated petcock - if not ignore this reply). If there is a problem with the diaphragm in the petcock fuel can flow through the vacuum line into the #2 carb and cause a rich condition. One easy way to check this is to put a clean spark plug in #2 cylinder; disconnect the vacuum line from the #2 carb and plug both the vacuum port on the carb and the petcock vacuum hose; and then run the bike with the petcock in the reserve position. If the problem goes away the petcock is at fault. If the problem persists you can rule pretty much out the petcock as the source of the problem. Ed

Steve- will do, chief! Short and simple tester to see what happens.

Ed- I just replaced the entire petcock unit yesterday with a new replacement one (brand new) so I ruled put that being the issue. I had issues with it before doing the same but wet fouling when I ran the stock petcock. Checked the line for kicks last night after the new petcock was on and it's dry.

Which leads me to think it's a spark plug cap, lead, or coil. I'll swap #2/3 leads to see if the issue follows it.

Thanks for the tips guys!

Devin

How is #2 carb holder?
Steve

I haven't checked them in a while. If one is cracked, would it not lead to a lean condition?

Sure, it won't be burning like the others. Check where it fits against the head. I used Permatex to seal my old ones. Worked long enough for me to get new ones. Now I have them on the door to Bossie's shed for carb adjustments.
Steve

Steve- will do. When I rebuilt her the first time (4 years ago), any rubber that looked aged or drying at all got replaced- so I did the orinhs on the backs of the boots. I'll check the boots though and see what they look like. I like the idea with the old boots... out of curiosiry- where did the name Bossie come from for your girl?

Very handy place to work on them
The kids named her Bossie the Kaw when they were young. My 69 Ford F250 is called Bertha.
Steve

Oh for sure it is. Beats my ardox nail on the garage wall beam and hanging the carbs up by the spacer body.
Oh I see, that's awesome I haven't quite come up with a name for this little hell cat yet...

Dang. I feel so late to the party here...

Devin! Glad that new Suzi petcock worked out for you too. How funny, that you got one a month after I did and yet you have already ran more gas through it
Maybe I shouldn't be sticking my nose in here since I ain't got my 650 to even start yet but...

So on your (un-named as yet) 650; isn't carburetor number two the one with the accelerator pump too? My number 2 carb has that so I wondered if it's somehow related? I know it has an adjustment screw.
When I rebuilt them (no, really. I swear I did! ) I noticed how the bowl on #2 was also different along that small-externally-connected-by-rubber-fuel-rail. The gasket on #2 bowl had an extra hole (which my new gaskets did not, so I had to razor knife it into the gasket)...

Did swapping the High Tension leads between 2 to 3 make any difference?
I have a new but quasi coil that fails once warmed up, So, I tried changing HT leads between 1 & 4 and then ultimately between 2 & 3 and then eventually swapping the coils entirely at their input wire connections to isolate the fault to a specific coil from the points etc.

Hope all is well!

Wrench- better late than never, right? She sure did work out! Alot easier to run as well. I like how small and tidy it is. Stick your nose in whatever you want! Anything helps out here.

So with this unnamed beauty, I actually don't have the accelerator pump as this is the older '78 650. I think the accelerator pumps came into play on the '80 650's and newer. So that one is out

As for swapping the leads- the shop that put the leads on left only enough meat to get JUST to each cylinder it's supposed to supply- therefore I wasn't able to swap the leads... However, although I haven't been able to swap the leads, I have noticed one thing on Cyl #3. When I start it cold, cyl #3 takes a little while to warm up. ie-- feel the header pipe, 1, 2, 4 are warm/hot within seconds. #3 I can hold my finger to for a little bit before taking it off. So what I'm thinking here is a few things. 1- float level is off a little and it's causing it to run rich on starts. BUT when the bike is warm, it doesn't foul the plug- the plug runs coffee and cream coloured. So I'm thinking that one is out. #2- the coil is starting to fail, therefore leading to #2 burning colder if there is increased resistance in the coil/lead.

I warmed the bike up, went for a ride, then got out my colortune unit and checked the pilot burn color on that cylinder. It's borderline rich/starting to dial in and burn blue with the pilot turned out 5 turns (almost far enough to fall out).

What I'm thinking here of what could be done:
1- coils and leads changed to get rid of any potential issues
2- check float bowl levels yet again and maybe lower #2/3 a hair if needed.
3- there's SOME sort of junk caught in some air passage way that I haven't managed to let loose yet that is causing the pilot screw to not let the proper amount of air in.
4- the pilot jet that is in #2 is labeled as a 17.5 (size of all others now). BUT could it maybe be mislabeled and be richer?

At least I can ride it, the petcock is sorted out, and the plugs burn MUCH better. And she's more of a rocket now. I notice the "burble" The most maybe between 1/4-1/2 throttle- right where the pilot/needle start to mesh. Any input from anyone is appreciated.

Devin

I forgot to mention in the last post- I disconnected the petcock just to check. Ran it with the vacuum line plugged and wide open, made no difference to the running. So that is ruled out as well.