1980 XS Eleven won't idle or rev up

[doctorjay13]

Hello all! A brief "excuse" first...I'm a former Auto Tech of 25 years who made the switch to prison guard, so shift work and on-call duties have severely limited my available diagnostic time. I thought I'd ask here 1st in case this was a common problem.

My 1980 XS had a complete going over 2 years ago: new tank, COMPLETE carb rebuilds, as well as rebuilt petcocks and new strainers, etc, etc.The bike ran fantastic and ran that way when parked last year. I always drain the tank and carbs for storage and bring the battery inside. After a new battery and a tank of fuel, the season's first start was disappointing...It fired up right away on full choke, but when I put it on the second step of the choke to lower the rpm- it stalled like someone shut it off with a switch. It restarted fine, but stalled the same way when I cracked the throttle. It won't run without the choke- no idle and every time I crack the throttle it "lean pops" in the airbox and stalls. Fuel delivery to the carbs is good and whenn I pulled the rack of carbs out and checked for debris or plugging of jets I found the carbs to be as clean as after the rebuild. My spark tester shows that it doesn't lose spark either when it stalls. It seems to be a fueling issue, but I'll be hanged if I can see where the problem is. When set to full choke, it will run by itself but stalls if I even think of opening the throttle. The carb intake boots are new as well and I checked for vacuum leaks and found none. I know it's not engine internal mechanical problems like hanging valves as it ran fine when parked and has great cranking compression and runs smooth on full choke. It seems super lean, but I'm not sure why. My time to rip and tear is limited since our justice system and crime rate leave me with almost no free time at all. Any tips would be appreciated...I can't keep pulling the carbs for no good reason other than to practice cussing...amd I need no help in that department!

Thanks for looking....

[BA80]

My 1980 XS had a complete going over 2 years ago: ....

Those carbs are gummed up again after 2 years.


Pull 'em.......clean 'em. The passages are clogged up.

[DGXSER]

Hate to say it , but yes they sound clogged. Pull the jets out and spray with carb cleaner through all the passages, including the enrichment jet in the float bowl.

[TopCatGr58]

Hey DoctorJay,

Unlike car carbs, these carbs are a bit more sensitive and as has been stated, the pilot circuit/low rpm circuit jets and passages are easily clogged/gummed up with even the littlest of fuel residue! So...yep, pulling the carbs, the pilot, main jets, the main jet needle/emulsion tube need to be removed, soaked, cleaned. THEN, next winter, put some Sea Foam, Berryman's in the tank and run it thru before draining the system. Some of us run the same every few tankfuls just to help keep things cleared out.

T.C.

[trbig]

My first step would be the "Tune up in a can" Seafoam. Put a half can of it in your gas, start the bike up for a bit to make sure the cleaner gets into the carbs, then kill it and let it sit a bit. (Like overnight). I'm betting that by the time you run that tank of fuel through, since it does run, that it'll get you pretty close to fixed up. Or at least get you by until you've got time for a proper carb cleaning. And as TC said, the Seafoam also makes an EXCELLENT fuel stabilizer for storage.

There are some cheaper products out there, but this is a case of getting what you pay for.

[doctorjay13]

Thanks for the tips...The carbs are out and apart; ready for soaking. I'll let ya know how it turns out when I have time to put them together and fire the boilers.

[TopCatGr58]

Hey DoctorJay,

Your reply was late last night, my reply was a little sloppy in combing the carbs with the parts and the words SOAKING!? I hope you've read thru the carb tech tip and learned that you do NOT want to soak the actual carb bodies...at least not in any caustic carb cleaner. I meant soaking the metal parts removed from the carbs only! Hope you didn't/haven't soaked the carb bodies in carb cleaner, otherwise damage to the butterfly shaft seals will occur!

T.C.

[doctorjay13]

...Understood! I have some seafoam...BUT the carbs did undergo some soaking a few years ago and have performed flawlessly since- must have gotten lucky!

[doctorjay13]

UPDATE- thanks for the advice...the low speed jets flowed air and brakeclean, but when probed with soft wire, some green crap came out; the slight restriction must have been enough to lessen the vacuum signal and foil whatever atomization was trying to take place. I put about 200 km on it yesterday and it runs great. It,s gonna be hard to NOT call in sick from Sturgis...