What is next to fix my rich condition on left cylinder?

[sdxs2]

So I have been chasing my issue for a while and cannot seem to get my left cylinder into a normal state.

My setup is a 72 with vm34s with plastic floats. Pamco harley dual fire coil, new 5k caps and wires.
I have ruled out many things. Valves were set good when I got the bike and have hot ridden more than 100 miles. Eliminated coil and spark by switching plug wires. This happened with points ignition also.
Carbs have new float seals and adjusted 22 to 23mm. New o rings in mixture screws.
Have also checked for intake leaks and finally tonight switched choke plungers and didnt seem to change on a short ride. Also have tried different jets. Sync should not be far off.

I am at a loss of what it is. Black sooty no matter what I do.

Finally a pic of where I am at with my build. From scrap pile for free to this....yes free.

 

[TwoManyXS1Bs]

Coupla thoughts:
The carb in the pic looks like BS34, not VM34.
The pod airfilter has an inner lip with a history of interfering with the upper diaphram port.
Is the diaphram OK?
Is the left exhaust compression release disabled or adjusted so that it's not interferring with the exhaust valve?

 

[sdxs2]

Compression is good I have removed the compression release cable and use kick start. Your correct on BS34s, my mistake. These pods dont have the inner lips. Diaphragms go down slowly when covering the hole on the carb.

 

[TwoManyXS1Bs]

Well, I'm not very familiar with those carbs. All I got left is to suggest the 'clear tube method' to confirm float heights, and to ensure the enrichener fully closes...

 

[cruzin]

Did you sync them? I fiddled with my 01 shadow for a long time to get it to burn proper in both cylinders but until I sync'd the carbs I had no positive results. I made a cheap plastic tube taped to a yard stick and threaded some brake line tube to screw into the passage way and the sync was way off. After I sync'd them it has ran great and still does.
By the way nice deal on the bike! looking good

 

[sdxs2]

I had sone time tonight and got out some tube and trans fluid. Carbs are synced now and I never realized how sensitive that adjustment screw can be. I bet it was half or three quarter turns off is all. Definately found a good spot and went for a short spin and initial plug reading is that I am on to something. I will have to get new plugs and start fresh. Probably next week or maybe this weekend.

If this is it I am gonna be excited to move forward on my build this winter and be ready for spring.

 

[cruzin]

thats great news. syncing is a very needed deal. I did not realize it till I added jet kits had the carbs out of my shadow at least 5 times till it dawned on me...they needed synced.

 

[sdxs2]

Well my sync is on and have the same issue. It is better and each side sounds the same also. Tried adjusting past to lean out the left side but didnt work. Will have to start switching more carb parts I guess unless someone has another idea.

 

[5twins]

Have you removed, inspected, and cleaned your needle jets? If not then I would do so. Clogged needle jets will cause rich running.

 

[plane_ben]

Left cylinder richness is a well know problem with the XS650. The only way I have ever heard of it being fixed with twin carbs is with XSJohn's needles, and unfortunately he has passed. He fiddled with this problem for years and came up with some needles that had a slightly richer profile for the right carb so it would run richer. If you take a temp gun and measure while the engine is running, you will see the right cylinder is running hotter than the left. My last twin carb bike was about 20 degrees difference.

You may notice, I keep referring to twin carb setups. For some reason, and I can't explain it, my current single carb setup has no left cylinder richness issues. I don't know if it's the single carb, or the re-phased engine, but my left cylinder problem went away. Cylinder temps are pretty even also.

There is some very good information on carb tuning in XSJohn's modifications here on this site. Hope this helps some. Nice looking free bike BTW.