Post carb cleaning woes!

Hi everyone! I purchased an 85' XJ700 a few months ago (~40k miles). She ran fairly well though I always had to have the choke atleast half way open. I subsequently pulled and cleaned the carbs two weeks ago. They looked relatively clean and I had no major difficulties with the process. Once I placed them back on the bike, it started right up and idled well though would immediately die when I gave it any throttle. Assuming I had an air leak, I resealed the boots, placed a new air filter, and then recleaned the carbs again yesterday. It seems to have helped quite a bit and the bike now responds pretty well to the throttle. However, when I try to start going forward, she will die unless I rev the engine up to ~3 or 4k rpm and then start letting off the clutch. Anyone have any ideas why this is the case? I'm fairly certain that I've eliminated any source of air leaks, and the carbs look great.

And a second, possibly related question. After owning the bike for a couple months, I noticed that occasionally not all of the cylinders will be running (alternates between which ones, apparent when the header(s) will still be cold). When I pull off the spark plug, clean them, then replace, it typically fixes the problem. However, it has repeatedly happened. Does it sound like I'm combusting some nasty crap in there that are covering the plugs? Or perhaps I should just purchase some new plugs? When I received the bike, there was no air filter in place, something which I recently replaced.

Sorry if these are a tad long winded. Thank you!

Andrew

 

Welcome! I can't personally be of much help, but you've come to right place and I reckon the rest will be along shortly.

Don't sweat the long posts, the more detail you can include the better the response you will get.

 

Running the bike with the "choke" on will foul your plugs quickly. Do you still need to leave it on?

Have you checked your valve clearances?

 

So far I have to leave the choke/EC open about 1/4 of the way while she's just idleing. I might be able to close it after she's fully warmed up though I've yet to ride her to that point due to the current condition.

Can you tell me more about checking valve clearances? I'm unsure what this refers to!

 

Don't worry about Valve Clearances and get your head back into the Carbs!
You're Tuning the Carbs.
Got a screwdriver that fits the Pilot Jets?

Does the Bike Idle?
How?
Did you Bench Sync the Throttle Plates before installing them?

Needing to run with the Enrichment Open means you have a Fuel delivery related problem of some kind.

Where are the Pilot Mixture Screws set to at the moment?
If they are 2-1/2 Turns out or less ... reset them all.
3-1/8th - Turns OUT ... for Starters.

See how she runs like that and report your findings.

 

I KNOW I KNOW!!! absolutely listen to Rick, he's a good man, but I did this for 15 MONTHS and finally narrowed it down to the TCI box. I'm assuming you don't have a Colortune plug, get one, PLEASE. if not for this problem do it for getting a perfect tune. When I used the colortune, because I had nothing left to do except sell or give the damn bike away I learned something Crazy. I"m getting a spark, one that's visible with the naked eye through the Colortune window, but no combustion every stroke, on 2 & 3 cylinders only. about every 10 strokes they'll be a huge orange explosion telling me the fuel that's accumulated in the chamber finally burnt. Well I knew that those 2 holes would be too much of a coincedence for the carbs to be clogged in the exact same places since i cleaned them about 46 thousand times so it had to be my ignition. I switched some things around and learned that the problem is behind the coils. New TCI on it's way but I"m most confident that's the problem. I was able to replicate the problem on cylinders 1 and 4 by switching things up. Good Luck bud. Just trying to help cause I've been chasing this gremlin for 15 months and finally have some insight thanks to the colortune. I had the same problem that the bike would stumble w/ throttle. Once I colortuned the 2 working cylinders, it picked up RPM's nicely and the other holes would eventually fire All The Time above 2500.

 

When you say it don't start "Hitting on all-4, ... Until you reach 2,500 rpm's.
I get a hinky feeling your problem isn't the TCI.
I think you are fighting for AMPS to keep everything working and don't have enough power being made until the System reaches enough power to have everything getting enough juice.

See what your Battery shows at: 1050 -- 1850 -- and, 2,000 and above.

The Alternator Brushes are in the Cover.
Measure.
10 mm or Less ... Get New ones.

 

i agree with rick again voltage will mess things up badly. i went thru the hole ignition system on my virago replaced pick up coils tci 2 sets of coils rewired from the tci to the coils ended up being a weak battery i would use a battery charger while cranking it . the battery charger was causing the tci to think the pu coils were telling it to spark. so all you had to do was bump it over and plug would start to fire and had continous spark like a welder. bought a new battery cranked it up been running good ever since . also for a quick check if you dont have a meter to check voltage pull the fuse for the headlight see if it fires any better that gets rid of most of the load on the charging system

 

Wilcons, I hope this helps lol, i'm am certainly not trying to steal your thread. My battery was purchased about 6 months ago. last charge was a few weeks ago, usually around 13V when it comes off the charger. Just went to the bike, 12.2 volts as it sits. started her and it went to 11.6 idleing at 1050. couldn't increase the RPM's because IMO the TCI is having a bad day lol. sometimes I can and sometimes I can't. so I don't have V reading at higher RPM, wait, going to pull the fuse for headlight... it was 11.9 with the fuse out and running

 

proves my point as well as ricks it might not be the problem but its worth checking.

 

Thanks for all of the help! Awesome forum. I'm going to mess with the air mix screws this afternoon and see what kind of results I get.

Cheers,
Andrew

 

sooooo do you think i'm good? lol I would think so, bike was cold and had not time to recharge. I was able to recreate the problem on the opposing cylinders by reversing the low tension leads and plug wires. I'd be blown away if low voltage would choose one path in the TCI to one coil. always worth checking? Absolutely. thanks so far ya'll
Wilcons, Let us know!

 

if you can recreate the same symptoms when you switch the wires on the coils sounds like it might be the tci. i had a conversation with a tci rebuilder when i was having trouble with my virago he explained how it works i believe he said the secondary voltage cuts in at 2500 or 3500 i dont remember wich one but he said it comes on real hard when it comes on. and it gets worse at low rpm the hotter it gets. he also said it will start cutting out faster and faster till it wont fire at all . i dont know if you cleaned the connections on the tci but thats another thing he told me to check he said if the sit or in a humid place ir gets wet the corrosion on the connectors causes alout of problems.keep us informed on the progress

 

ha! that's exactly what's happening, BUT, if it comes on at 2500 or whatever, then how the hell can you tune at idle? oh well, I don't need to know, that prety much just put a nail in my TCI's coffin. Thanks man

 

Update!

So, I did some fine changes with the pilot air mixture screw and had so so results. Opening the screws just past three turns did seem to make the bike easier to ride forward. However, it also made the bike feel fairly sluggish. You know that sound when you are in too high of a gear for the speed you're traveling at, kind of a gurgling? This sound is more pronounced now.

I imagine this comes down to finding that sweet spot for calibrations - something which can be frustrating when you have to pull either the tank or the tank+carbs repeatedly! All of these fine tunings are starting to reach the extent of my know how...off to the shop, perhaps?