I am lost on this .............

Last november my XS starting to pop thru the carbs. When the motor was cold. Just a little worse each time I started it and it stopped when it warmed up. Then it became almost unrideable from the popping. Since I had lots of little oil leaks, I figured it was time to clean out the carbs and install new top end gaskets and seals. Got all the seals and gaskets replaced and put in a new cam chain ( timing chain ?? ) I had a couple of those orange boxed Keyster carb kits and cleaned out the carbs and put in the new parts. The parts in the kit matched what was in the carbs, except the slide needle and it's jet, so I reused the originals. All the passages seemed nice and clear. With the little pipe on the Gumout can, all the ports and passages flowed well, or at least I thought.

Got it all back together and it still poped out the carbs, not one, but both. If the choke was on, no popping and it ran great. Turn off the choke and it started poping just over idle about 2000rpm. It idles perfect, I mean one kick starts and perfect glass smooth idle. Took everything apart again, rechecked cam timing, ignition, points and anything else I could think of. Blew the carbs out with compressed air. And more carb spray. Put it back together and it still pops out the carbs with the choke off, put it on and run it around town and all is well, turn off choke, it is unrideable with the popping out the carbs. Pulled the carbs again, tied the carb body and the float bowl to the railing behind the shop, hit them with steam at high pressure. Thru all the passages and all the ports. I didnt miss anything I could think of, New carb holders and diaphragms from JBM. A neighbor says it is the spark plugs ........... huh ??

I ran this thing all summer with no problems, now the choke has to be on just to run it around the block.

Any thoughts are welcome..................

I'm off to the local Napa to buy plugs

Thanks

John

did you have the valves lapped when the engine was apart? could be valves not seating.

richen the idle mix abit?

no, I didnt think about doing any valve work, while it was apart. Main concern was stopping oil leaks. It pops like it is running lean, just the black poofy crap on the plugs look anything but lean ........ maybe I aint smart enough for this bike ???

I would do a compression check just to rule out a bad valve. also take off your air filters and see if it blows any gas out the carbs while it is running that could be a bad intake valve. where there a lot of miles on the engine?

Go up a pilot jet size or two and maybe increase the richness setting on your needle. I am thinking that you are running too lean.

Go back to basics...................have you checked that the float bowl levels are correct? Operation of the carbs depends on the levels being correct. Use a clear plastic tube from the drain plug as a level gauge.

Checked floats, checked fuel levels .............. Black sooty plugs and filthy black sooty exhaust. I am getting lost on this. It ram great all summer, then in the matter of about 6 weeks things went wrong fast. I have a chart that was sent to me by someone that shows what came from the factory in these carbs, and got things from MikesXS and matched the list. Went thru everything I could think of ( timing, points, cam timing, compression and anything I could think of ) I may have to have priest come here and do a blessing or exorcism , I don't know.

Wonder what this thing is worth ???

Maybe I could sell it and buy a Chinese scooter, atleast then I would expect things to go wrong !!

Thanks, have a few ideas to try sunday ............. then ???

If I'm correct, the choke is basically an enricher. When you pull it on a cold engine it forces the condensation, and some fuel stuck to the sides, out. If that helps.
If it were me I would buy all new jets, clean the carbs again, and go from there.

Someone else on here stated in another thread that they had bought chinese or some other manufacturer jets and they caused a problem.

Also make sure you get the correct jets.

I bought a bunch of stock jets from Mikes, and made sure they were right. Something I was curious about, I was looking at some exploded views of these carbs, could the seals on the butterfly shafts be causing all the tail chasing I am doing on this damn bike ?????

What are they, just O-rings ?

www.amckayltd.com/carbguide.pdf might help.

Post 7: Sealing Air Leaks, in the carb guide XSLEO liked ^

definetly sounds like air leaks.

Sounds like that to me also. The carb holders can crack and let air in.
The carb guide is a good thing to read it will help you understand your carbs better.

The carb guide is priceless!! Im a believer!!

I will also say that the clamp on your carb boot needs to be tightened so both clamp ends are touching. I had a popping, tightened the boots per carb guide, and perfect now.