Carb issue

[Randy N]

I am having some issues with the left carb on my XS2. it’s been a lot of years since I’ve been into one and wanted to ask a couple questions and pose the problem before I get into it.
The left cylinder is not firing at idle, and if I play with the throttle and gently bring it up off idle, it will fire and then run fine. If I crack it open from idle, the bike will die. The right cylinder is firing fine. I am certainly getting a lot of black smoke so it seems to be running rich. I checked the timing and the points and recapped them as the left side was not gapped properly.
I did ask the previous owner where he had the needle clip set and he does not recall. I’m thinking I should pull the left carb off and go through it.
Any thoughts or advice from the group here?
Thanks

 

[JJames]

If the points weren't firing properly, it may have fouled the left plug. Failing that maybee needle and seat or float height issue..

 

[Randy N]

If the points weren't firing properly, it may have fouled the left plug. Failing that maybee needle and seat or float height issue..

Thanks!

 

[Randy N]

I pulled the car apart and looks like all new parts inside. The mid range needle was on the bottom clip so I moved it up according to the shop manual.
I put it all back together, and it seemed to start better, but the left side is still not firing at idle. if I bring the left side up off idle, the left side kicks in I get pillows of smoke and then it runs for a bit and then I can let it back on an idle and it will fire for a while and then slowly the left side quits.
I pulled the plug and it is not black and it is certainly wet.
This sounds like a carb issue to me, but I’m not sure what.
Too many years have gone by since I’ve worked on carbureted engines.
Looking for any help

 

[Bruno_c]

Did you clean the pilot jet and check the float height?

 

[Wingedwheel]

If it’s new parts they need to be checked to make sure they are the right size and fitment. Generic Chinese kits do more harm than help. Check out the carb guides under tech for all your information.

 

[Kevin Werner]

Have you check mechanical sync? Have you checked sync with vacuum gauges?

 

[Wingedwheel]

You need to see if your brass matches what’s on the chart and as Kevin mentioned, syncing. Those carbs are unlinked so they require a little extra fiddling with.

 

[Randy N]

View attachment 325763
You need to see if your brass matches what’s on the chart and as Kevin mentioned, syncing. Those carbs are unlinked so they require a little extra fiddling with.

Thanks for the replies. I will pull it off and strip it down and check it all against spec.

 

[Randy N]

Did you clean the pilot jet and check the float height?

Float height was too high. I did drop it. I measured without the gasket. Is that correct?

 

[Randy N]

Have you check mechanical sync? Have you checked sync with vacuum gauges?

Mechanical sync is good. Haven’t used vacuum gauges yet.

 

[Randy N]

So here’s where I’m at today. I pulled the carb apart and went through it and cleaned it. Nothing spectacular showed up anywhere, and I also blew the whole thing out with compressed air.
Still made no difference and the left side w would not fire at all.
I turned my attention to the points and timing again. I can get the right side timed properly and the right gap. The left side are offshore points and I had a hard time getting the gap set and here’s a picture of the most advanced I can get the timing on the left side. The left cylinder will fire when engine hits 3000 RPM or so and I get great cloud of white smoke. I’m thinking the spark advance finally gets it far enough advanced that the left side is firing properly so to speak.
I do have points on order and they are OEM.
Just wanna get some thoughts if I’m going down the right path here

 

[gggGary]

Check condensers.
Do the hot water dip test on the floats.
Timing light or just static timing?
Timing Light is better.

 

[Randy N]

I have to buy a new timing light. Apparently, I gave mine away a while ago.. So today was static timing.
I’ll do the hot water test on the floats

 

[gggGary]

did you remove and check pilot jets are open? pilots are most likely jet to clog.
Also remove needle jets check side drillings are clear.
They can be pretty happy to remain where they are, and will likely need a new o-ring.

torch that spark plug dry, check that the plug cap has correct 5K ohm resistance
Are you using NGK BP7ES plugs?
8s are colder, more likely to foul.

 

[gggGary]

points gap is a range if you need to open the gap some to advance timing on that side, do it.