Bike only runs with choke on.

Ok here goes. I bought a nonrunning 82 xs back in january.I was told it just needed a new tci. I bought a pamco instead,and installed it no problem.I have not been able to get it timed yet. At first it only started on full choke and shot right up to 4,000 rpms. It had been sitting so i got fresh gas and pulled the carbs and cleaned them,and also installed uni filters since it came with cone pods when i bought it. The exhaust is stock. Now when i start it,it still has to be on full choke but it only runs at 2,000 rpms now. I can push the choke in one notch and it'll kinda stumble idle at around 1,000 rpms. If i push the choke in any farther it dies.When i give it throttle it pops and stumbles and then catches. The carbs are running 132.5 mains. Oh i also replaced the plugs. The old ones were pretty black.Do i need to up the mains or something else going on here?

Start with the pilot circuit
http://www.amckayltd.com/carbguide.pdf
and float height

Thanks man. Gotta love these old bikes.Think you have a problem fixed and discover several more lol

well the revving problem could be an issue with the cable adjustment or the linkage... but yeah, sounds like a stuck jet.

when you say you pulled the carbs and cleaned them, what exactly do you mean? How far apart did you pull them when you did this?? Did you adjust the vacuum balance when you reinstalled them on your bike?

I had a problem recently with my XS running like shit. It felt like it was only runnint on about 1.5 cylinders, acting lean, stalling, erratic idle, etc... So I re-adjusted the PAMCO plate to proper marks with a timing light-- on both cylinders---- then attached a vacuum balance gauge and checked the vacuum balance. While adjusting the balance there were several points where the engine revved way up and I had to back the idle screw down to fix get the engine to run normally. If you have never done this I HIGHLY RECOMMEND IT. Proper vacuum balance is SO IMPORTANT on any engine with multiple carburetors. The BS38/34 carbs adjust really easy, there's a screw in the middle of the linkage. This is not something you can easily do by ear, you need a balancer gauge--- dont even think of trying it without the proper tool you'll just make matters worse.

my bike runs like a different machine altogether now. Now there are no stalls, idles smoothly, no terrible backfiring, it pulls harder in every gear and has no problem screaming up to 5000rpms (I dont run it harder than that) and the sound is much better through the straight pipes.... oh yeah! Do it! You know you should! Your bike will love you for it!

Nothing like a major tune up to make a bike run right.

Nothing like a major tune up to make a bike run right.

Click to expand...

yes! Do it! you'll be glad you did!

Thanks for the info. I'm totaly new to restoring an old bike or even working on them. When i said i 'pulled' the carbs i meant that i took them off the bike to clean them. No i didn't adjust the vacume balance. I guess i need to order the tool. I printed and have been reading the carb guide,it helps but it kinda seems overwelming to someone who hasn't done this kinda thing before.
I havn't been able to get it timed cuz i havn't been able to get it to idle properly. The timing guide says i need to check it at 1200 rpms and 3000 rpms. I havn't been able to get it to do that so i figured i should work on that problem first.
I may have done a subpar job in my cleaning.I noticed the head of one of the fuel screws is all chewed up(from a p.o. i never touched it before) and i can't get a screwdriver in to take it out. It's been almost completely stripped.Is there an easy way to get it out?
Thanks again for the help.

"fuel screws" - you mean the tiny screws on top in towers? If it's stripped, find the smallest easy out you can, drill *very* carefully into the brass, and ease it out. P.O. has probably lost the washer/o-ring that's supposed to go in there as well, so just order a couple of kits.

Hmmm.... "fuel screws"?? Carbs have so many tiny screws in them. The Jets themselves look like tiny screws--- and they are recessed so you need a tiny screwdriver to remove them. The holes in the jets that the fuel runs through are just a few thousandths of an inch wide and can plug easily from even the tiniest metal shaving or grain of sand.

Just pull the diaphrams off and wipe them off with a clean rag. Scrub out the bowl with a toothbrush and some mineral spirits (try not to disturb the float-bowl gaskets so you can re-use them), if the needle is crusty then clean it and clean down inside the needle seat with a tool like a q-tip or a golf tee with a dab of car polish. pull the mixture screws out and clean them off. pull the main jet out and use carb cleaner or solvent and more q-tips to clean out the 'varnish' or the 'chalky' stuff or the 'muddy' stuff or whatever is in there. Then you can gently scrub the outer surface of the brass jet with steel wool and make sure the whole thing is clean and there is no gritty leftovers to plug up later on--- if need be, use a single bristle from a wire brush to clear the jets. it really is best to blow it off with compressed air-- check and double check that it's clear before you put it all back together... or else you'll just piss yourself off. Try blowing air (I used canned air) though all the passages and make sure they aren't plugged.

you can do this operation in a nice clean oil-drain pan in your lap while you sit in a comfortable chair so all the parts stay in one place and none get lost and you dont get too sore. Try not to move the vacuum balance screw in the middle of the throttle linkage too much...

after you put it all back together you'll need to set the mixture, the idle, and most likely the vacuum balance. Honestly you may be better off if you could have someone else show you how to balance, it takes like 10 minutes once you know what you are doing but it can be frustrating and there's a bit more to it than just having the gauge...

I think i meant the fuel mix screws. The ones that are supposed to be under a cap on the bs34s.
I actually found out that a friends dad works on carbs for a living. He agreed to walk me through the process. Thanks for all the help. I'm sorry about all the confusion in my posts.

There's a specific order to the parts on the BS34 mix screws. Mix them up or be missing any and the screw won't function properly .....

Dude Maverick, that's totally AWESOME man--- learn all that you can. Once you understand what's going on with the carbs they are simple to work on these older bikes. No computers or sensors or any of that B.S.

good luck to you on your new quest

I just made a note of that 5 thanks man. Thanks JR I'm definatlely lookin forward to workin personally with someone who actually knows what he's doing. I can't wait to get this bike running!

right side pod filter was nearly on fire too.

Could this be from a bad valve adjustment?